bluuebunny/crossref_metadata_2025_split huggingface dataset:
Symmetry of Strong Interactions
Authors: Nakamura Seitaro , Sato Shigeo 
Published: December 2007

The symmetry of strong interactions and weak interactions is formulated in terms of the four-dimensional charge space of SU(2) × SU (2) or O (4), where the isospin, τ, and the “hypercharge spin”, ζ, are considered as two independent spin matrices. The wave functions of baryons and mesons in this charge space are assumed to be composed of the eigenfunctions t of τ3 and s of ζ3, and to transform according to the representations (1/2, 0) and (0, 1/2), respectively. As the basic wave functions which span an irreducible representation space allowing the reflection operations in the charge space, which give rise to the transformations we need sixteen kinds of baryons and also sixteen kinds of mesons, if we assume that the ground state particles are described in terms of the bilinear products t*t, s*s t*s and s*t. The sixteen kinds of particles are made of a singlet, a triplet and a quartet which correspond to an octet in SU (3) symmetry and their countermultiplets which come out by exchanging t⇄s. Among the latter multiplets, a “hypercharge spin” triplet of baryons Z+ (Y=+2), Λ*(Y=0), Ω−(Y = −2) and of mesons D+ (Y=+2), D°(Y=0), D−(Y=−2) are introduced as the countermultiplets of ∑ hyperon and π meson, respectively. We also attempt to classify baryon isobars and meson isobars in terms of the higher configurations of t, t* and s, s*. It is remarkable that a new selection rule of “hypercharge independence” is very powerful in explaining the suppression of some of the decay modes which are otherwise hard to understand. It may also be satisfactory to see that the allowed modes are described in terms of Symmetric interactions, while the forbidden modes of decay are invoked in terms of the meso-strong symmetry breaking interactions on the basis of the present scheme of SU(2) × SU (2) symmetry. The possible experiments which could afford tests of the present scheme are cited within the framework of strong interactions only.
We extend the theorem by Okun and Pomeranchuk for high energy scattering in the asymptotic region to include hypercharge independence in addition to charge independence, and obtain good results in the case of kaon-nucleon scattering; we also obtain predictions which can be easily tested by the experiments in the case of antiproton (proton)-nucleon scattering in the asymptotic region. Discussions are made on the various results deduced from the present scheme of SU (2) × SU (2), in comparison with those obtained from the SU (3) scheme.
New data on
Kimberella
, the Vendian mollusc-like organism (White Sea region, Russia): palaeoecological and evolutionary implications
Authors: Fedonkin M. A. , Simonetta A. , Ivantsov A. Y. 
Published: December 2007

Abstract

The taphonomic varieties of over 800 specimens of
Kimberella
(collected from the Vendian rocks of the White Sea region) provide new evidence of the animal's anatomy such as: shell morphology, proboscis, mantle, possibly respiratory folds and possibly musculature, stomach and glands. Feeding tracks, crawling trails and, presumably, escape structures preserved along with the body imprint provide insights on the mode of locomotion and feeding of this animal. The shield-like dorsal shell reached up to 15 cm in length, 5–7 cm in width, and 3–4 cm in height. The shell was stiff but flexible. Evidence of dorso-ventral musculature and fine transverse ventral musculature suggests arrangement in a metameric pattern. Locomotion may have been by means of peristaltic waves, both within the sediment and over the surface of the sea floor, by means of a foot resembling that of monoplacophorans. Respiration may have been through a circumpedal folded strip (possibly an extension of the mantle). Feeding was accomplished by a retractable proboscis bearing terminal hook-like organs and provided with a pair of structures interpreted here as glands. Whilst feeding,
Kimberella
moved backwards. The structural complexity of
Kimberella
poses questions about the time of origin of the triploblastic metazoans.
The provenance and palaeobiology of a new multi-vaned, chambered frondose organism from the Ediacaran (later Neoproterozoic) of South Australia
Authors: Jenkins R. J. F. , Nedin C. 
Published: December 2007

Abstract

The new, large, frondose and stalked, Ediacaran (late Neoproterozoic) ‘petalonamid’
Pambikalbae hasenohrae
gen.
et
sp.
nov
. is preserved in a three-dimensional manner within sandy channel fills occurring directly below the Ediacara Member of the Rawnsley Quartzite on the ‘Nilpena’ pastoral property at a western outlier of the Flinders Ranges, South Australia.
Pambikalbae hasenohrae
was made up of numerous chambered vanes supported by a tapering axial stem and an anchoring stalk. Chambers forming the vanes were commonly infilled with sediment, though variably flattened; groups of vanes representing individual specimens can extend as much as
c
. 3.7 cm deep through the hosting sandstone matrix. Several series of chambers present in each vane abut at zigzag sutures.
Pambikalbae
is clearly not a cnidarian sea pen, but nevertheless exhibits characteristics suggestive of an evolutionary grade comparable to that of known modern cnidarian divisions. Though the serial geometric configuration of its thin integument seems ideally suited to house symbiotic microbial photoautotrophs, our appraisal of the palaeoecology of
Pambikalbae
is supportive of its being a heterotrophic suspension feeder.
Pambikalbae
may plausibly be a highly derived hydrozoan, part of the ancestral stock of the Siphonophorida, or a sister group to the early Chondrophorina.
Upper Vendian assemblages of carbonaceous micro- and macrofossils in the White Sea Region: systematic and biostratigraphic aspects
Authors: Leonov M. V. , Ragozina A. L. 
Published: December 2007

Abstract
Complexes of microfossils, consisting of spheromorphic acritarchs, and coccoid and filamentous cyanobacterial colonies, characterize distinct levels of the Upper Vendian sequence (Ediacaran) of the White Sea region. Three discrete assemblages of algal macrofossils have been recognized in this succession. The oldest assemblage is characteristic of the Lyamtsa Formation of Early Redkino age, the middle assemblage, the Verkhovka, Zimnegory and lowermost Yorga formations of Late Redkino age, and (provisionally) the youngest assemblage, preserved in the upper part of the Yorga Formation of Early Kotlin age. The Vendian succession studied here can be correlated with a similar succession in the Podolia region of Ukraine.
Climates and climate zonality of the Vendian: geological evidence
Authors: Chumakov N. M. 
Published: December 2007

Abstract
In view of the difficulties of stratigraphic correlation, the absence of being able to position continents reliably, the scarcity of climate indicators, and the fact that Vendian sequence crops out over a wide area and can be far apart, it has only so far been possible to identify the most general climatic features for three Vendian units. Late Vendian (Nemakit–Daldyn), and possibly Early Tommotian (Early Cambrian), time was characterized by a glacial climate with pronounced climatic zonation. It appears that there were northern and southern cold zones and a low-latitude, possibly mid-latitude warmer zones. Throughout the time the Middle Vendian sequence was being deposited (Redkino–Kotlin), a warm, possibly arid zone was characteristic of low and mid- palaeolatitudes. In southern high latitudes, there is evidence of a warm humid climate at some periods during this time. The Early Vendian (Laplandian or Varangian) time was characterized by a glacial climate. Some palaeocontinental reconstructions based on magnetism suggest that these glaciations affected high, middle and most of the low latitudes, extending to the palaeoequator. The timing of glacial events in the late Neoproterozoic and their extent across the globe and severity is a topic of great debate at the moment—some researchers suggesting glaciations that lasted for millions of years that locked the entire Earth in solid ice (‘Snowball Earth’). Others suggest that some ice-free oceans were present even during the most severe of glacial events and certainly some geological evidence seem to fit this latter hypothesis well.
Ediacaria booleyi
: weeded from the Garden of Ediacara?
Authors: MacGabhann B. A. , Murray J. , Nicholas C. 
Published: December 2007

Abstract

Sole markings from the Upper Cambrian Booley Bay Formation at Booley Bay, Co. Wexford, Ireland, previously described as the Ediacaran-type fossil
Ediacaria booleyi
appear to possess a number of morphological characteristics which are not consistent with assignment to the genus
Ediacaria
, nor any other known Ediacaran taxon. An inorganic origin for the structures has been proposed by several workers; we tentatively consider them to be at least in part organic, and are currently working to evaluate this hypothesis critically. If organic, the organisms must have had a density similar to that of the sediment in which they were emplaced, and to survive the transport process, they must have had a rigid integument. Neither of these properties appears to be consistent with an interpretation as an Ediacaran-type organism. We suggest here that the Booley Bay specimens should be removed from the genus
Ediacaria
. If
Ediacaria booleyi
is not related to known Ediacaran organisms, this would remove a key aspect of the argument against a mass extinction at the Precambrian/Cambrian boundary.
Seeing ghosts: Neoproterozoic bilaterian body plans
Authors: Valentine J. W. 
Published: December 2007

Abstract
Bilaterians originated before 560 Ma. By 520–530 Ma, the fossil record reveals a fauna teeming with bilaterians with highly disparate body plans, in which most living phyla must have been represented. Between these dates, few bilaterian body fossil types have been found, although trace fossils indicate the presence of vermiform animals, small-bodied before the beginning of the Cambrian. The diversity of Cambrian lineages implies a branch-rich phylogenetic tree, yet organisms representing branch nodes of phyla and ancestral alliances of phyla are unknown, and most of the branches are inhabited by ‘ghosts’. The body plans of these ghosts must be precursory to the body plans of crown phyla, and their genomes must be precursory to crown genomes. Bilaterian Hox genes mediate anteroposterior regionation and are usually found in transcriptionally colinear clusters, a feature conserved even when clusters have been broken up during evolution. When body sections mediated by Hox genes are reduced during morphological evolution, the corresponding gene is sometimes deleted. It may be possible to reconstruct the anteroposterior regionation of ghost lineages from Hox clusters modifications. More information on Hox gene assemblages and functions in small-bodied crown phyla, such as acoelomorphs and others, is required to explore this possibility more fully.
Non-destructive method to detect the cycle of lamination in sedimentary rocks: rhythmite sequence in Neoproterozoic Cap carbonates
Authors: Katsuta N. , Tojo B. , Takano M. , Yoshioka H. , Kawakami S. , Ohno T. , Kumazawa M. 
Published: December 2007

Abstract
Environmental changes were flagged by lamination within Precambrian sedimentary rocks sequences using a high-resolution method. A continuous sample was collected and embedded in epoxy resin to form sample plates in order to investigate 2D laminations on sample surfaces. Elemental distributions in laminated samples were determined and recorded as XRF profiles, using the scanning X-ray analytical microscope (SXAM) and an image processing lamination tracer.
These methods were used to study a rhythmite sequence at the base of a Neoproterozoic cap carbonates, which immediately overlies glacial deposits in Namibia, to determine profiles of Si, Ca, Mn, Ti, Fe, and Sr. At the base and top of each interval, the concentrations of six elements were relatively constant. In the middle of the interval, Ca–Sr and Mn, which reflect presence of calcite and dolomite respectively, fluctuated. This reflects seventeen cycles. The cyclic fluctuations of Ca–Sr and Mn were interpreted as calcite–dolomite cycles. Strontium also recorded two cycles. Furthermore, the fluctuations of Ca–Sr and Mn in calcite–dolomite cycles were laterally traceable. Possibly, these calcite–dolomite cycles were deposited synchronously and regionally. New methods allow the extraction of data that record cyclic- and event-phenomena from long sequences of laminated sedimentary rocks; this is not isolated to the Neoproterozoic but also throughout Earth's history.
Rugosoopsis
: a new group of Upper Riphean animals
Authors: Hermann T. N. , Podkovyrov V. N. 
Published: December 2007

Abstract

The Upper Riphean Lakhanda biota (from the Uchur-Mayai region of SE Siberia) contains abundant, well preserved and highly biodiverse microfossil assemblages including
Rugosoopsis
microfossils, characterized by a uniform shape, with prominent closely transversely spaced wrinkles on the outer surface.
Rugosoopsis
are the oldest, microscopic vermiform organisms, with a typical morphology of closely spaced wrinkles on the body's outer surface resembling the Late Vendian–Early Cambrian
Sabellidites
, and even more the smallest representatives in the genus
Sokolovina
Kirjanov, 1968 (Sokolov 1997). Different types of
Rugosoopsis
preservation can be explained by the presence of numerous bacterial microorganisms on the body of
Rugosoopsis
and on organic films.
Rugosoopsis
organisms inhabited the bottom, where they likely existed alongside saprophytic microbes in finely dispersed organic debris. The community of
Rugosoopsis
and bacteria appears to represent a stable trophic system. The exceptional preservation of these microfossils is due to the favourable sedimentary environment in the Lakhanda Basin.
δ
13
C stratigraphy of the Birmania Basin, Rajasthan, India: implications for the Vendian–Cambrian transition
Authors: Maheshwari A. , Sial A. N. , Mathur S. C. 
Published: December 2007

Abstract

The Birmania Basin is an oval-shaped, isolated remnant of the Marwar Basin (Neoproterozoic–Early Palaeozoic), located in the heart of the Thar Desert of western Rajasthan, India. The Birmania Basin comprises a 900 metre-thick sedimentary sequence of siliciclastic, carbonate and phosphorite facies. δ
13
C and δ
18
O-values are presented in this paper, based on samples of phosphorite and carbonate collected at close intervals along two sample lines near Birmania and Kohra in the Birmania Basin, Rajasthan, India. The carbonates of the Birmania Basin sampled have suffered neither deep burial nor alteration and may provide pristine samples of the C-cycle at the time of their deposition. These values can be useful in inter-regional correlation, particularly for unfossiliferous successions. The carbon isotopic pattern observed in the Birmania succession appears to be similar to that observed in well-established Precambrian–Cambrian boundary sections globally. A worldwide phase of phosphogenesis, at or near the Precambrian–Cambrian boundary, supports the inference that biological controls driven by ocean fertility changes influenced the marine carbon reservoir.
‘Ediacaran’ as a name for the newly designated terminal Proterozoic period
Authors: Jenkins R. J. F. 
Published: December 2007

Abstract
The ‘International Geological Commission on Stratigraphy Working Group on the Terminal Proterozoic Period’ held a series of ballots to vote for criteria identifying the new Period. These included establishing the international site and direct locality for the ‘Global Stratotype Section and Point’ (GSSP), as well as its stratigraphic level and the official name of the new period. Information included in the present note was submitted for circulation to members of the voting committee in April 2003 for their consideration on the occasion of the formal vote to ratify the name, and was a successful proposal for the designation ‘Ediacaran’.
The name Ediacara is historically established as an alliteration of the Aboriginal reference to an ephemeral lake recorded on the first geological map of the Flinders Ranges, and subsequently transmitted through references in Parliament, historical pastoral runs (named properties), and the surveying of a new mining town. During this history its application moved some 60 km south. The name refers to a place of water, possibly in the context of ancestral time. Aspects of the subsequent history of concepts embraced in the original presentation are included.
Effect of chronic treatment with acetylsalicylic acid and clopidogrel on atheroprogression and atherothrombosis in ApoE-deficient mice in vivo
Authors: Konrad Ildiko , Sauer Susanne , Orschiedt Lena , Koellnberger Maria , Lorenz Reinhard , Walter Ulrich , Massberg Steffen , Schulz Christian 
Published: December 2007

SummaryAcetylsalicylic acid (ASA) and the thienopyridine clopidogrel are established anti-platelet drugs that significantly reduce secondary cardiovascular events in patients with manifest atherosclerosis. However, their impact on atherosclerotic lesion development remains controversial. Four-week-old ApoE-deficient mice were randomly assigned to four groups receiving a cholesterol diet together with either ASA (5 mg/kg), or clopidogrel (25 mg/kg), or a combination of both ASA and clopidogrel, or vehicle for 8–12 weeks. Using intravital microscopy we found that daily administration of ASA in combination with clopidogrel reduces platelet thrombus formation following rupture of atherosclerotic plaque in vivo by ∼50%. However, therapy with ASA or clopidogrel alone, or in combination for a period of 8–12 weeks had no significant effect on adhesion of platelets to dysfunctional endothelial cells or on atherosclerotic lesion formation in the aortic root or the carotid artery. In conclusion, anti-platelet therapy is effective in reducing platelet adhesion and subsequent thrombus formation following rupture of atherosclerotic plaque in vivo. However, our data do not support a role of either drug in the primary prevention of atherosclerosis in ApoE-deficient mice.
Further validation and simplification of the Wells clinical decision rule in pulmonary embolism
Authors: Sohne Maaike , Kruip Marieke J. H. A , Tick Lidwine W , Gerdes Victor E , Bossuyt Patrick M , Wells Philip S , Buller Harry R , Gibson Nadine S ,   the Christopher study investigators
Published: December 2007

SummaryThe Wells rule is a widely applied clinical decision rule in the diagnostic work-up of patients with suspected pulmonary embolism (PE).The objective of this study was to replicate, validate and possibly simplify this rule. We used data collected in 3,306 consecutive patients with clinically suspected PE to recalculate the odds ratios for the variables in the rule, to calculate the proportion of patients with PE in the probability categories, the area under the ROC curve and the incidence of venous thromboembolism during follow-up. We compared these measures with those for a modified and a simplified version of the decision rule. In the replication, the odds ratios in the logistic regression model were found to be lower for each of the seven individual variables (p=0.02) but the proportion of patients with PE in the probability categories in our study group were comparable to those in the original derivation and validation groups. The area under the ROC of the original, modified and simplified decision rule was similar: 0.74 (p=0.99; p=0.07).The venous thromboembolism incidence at three months in the group of patients with a Wells score ≤ 4 and a normal D-dimer was 0.5%, versus 0.3% with a modified rule and 0.5% with a simplified rule. The proportion of patients safely excluded for PE was 32%, versus 31% and 30%, respectively. This study further validates the diagnostic utility of theWells rule and indicates that the scoring system can be simplified to one point for each variable.
Peroxisome proliferator-activated receptor γ and retinoid X receptor transcription factors are released from activated human platelets and shed in microparticles
Authors: Spinelli Sherry L , Pollock Stephen J , Murant Thomas I , O’Brien Jamie J , Blumberg Neil , Francis Charles W , Taubman Mark B , Ray Denise M , Phipps Richard P 
Published: December 2007

SummaryPeroxisome proliferator-activated receptor γ (PPARγ) and its ligands are important regulators of lipid metabolism, inflammation, and diabetes. We previously demonstrated that anucleate human platelets express the transcription factor PPARγ and that PPARγ ligands blunt platelet activation. To further understand the nature of PPARγ in platelets, we determined the platelet PPARγ isoform(s) and investigated the fate of PPARγ following platelet activation. Our studies demonstrated that human platelets contain only the PPARγ1 isoform and after activation with thrombin, TRAP, ADP or collagen PPARγ is released from internal stores. PPARγ release was blocked by a cytoskeleton inhibitor, Latrunculin A. Platelet-released PPARγ was complexed with the retinoid X receptor (RXR) and retained its ability to bind DNA. Interestingly, the released PPARγ and RXR were microparticle associated and the released PPARγ/RXR complex retained DNA-binding ability. Additionally, a monocytic cell line, THP-1, is capable of internalizing PMPs. Further investigation following treatment of these cells with the PPARγ agonist, rosiglitazone and PMPs revealed a possible transcellular mechanism to attenuate THP-1 activation. These new findings are the first to demonstrate transcription factor release from platelets, revealing the complex spectrum of proteins expressed and expelled from platelets, and suggests that platelet PPARγ has an undiscovered role in human biology.
Assessment of ADP-induced platelet aggregation with light transmission aggregometry and multiple electrode platelet aggregometry before and after clopidogrel treatment
Authors: Braun Siegmund , Jawansky Stefan , Vogt Wolfgang , Mehilli Julinda , Schömig Albert , Kastrati Adnan , Beckerath Nicolas von , Sibbing Dirk 
Published: December 2007

SummaryThe level of platelet aggregation, measured with light transmission aggregometry (LTA) in platelet rich plasma (PRP), has been shown to predict outcomes after percutaneous coronary intervention (PCI). However, measuring parameters of platelet function with LTA is time consuming and weakly standardized. Thus, a fast and standardized method to assess platelet function after clopidogrel treatment would be of great value for clinical practice. A new method, multiple electrode platelet aggregometry (MEA), to rapidly measure platelet aggregation in whole blood has recently been developed. The aim of this study was to assess parameters of platelet function with MEA and LTA before and after administration of 600 mg clopidogrel. Blood samples from 149 patients scheduled for coronary angiography were taken after clopidogrel treatment; in addition, in 60 of the patients samples were available before clopidogrel treatment. ADP-induced platelet aggregation was measured with LTA and simultaneously in whole blood with MEA on the Multiplate analyzer. Platelet aggregation measured with MEA decreased significantly after clopidogrel treatment (P<0.0001). ADP-induced platelet aggregation assessed with MEA and LTA correlated significantly (Spearman rank correlation coefficient=0.71; P<0.0001).The results of MEA, a fast and standardized method to assess the platelet response to ADP prior to and after clopidogrel treatment, correlate well with LTA.