Prolonged Time Span Research Articles

Thermal decomposition of PETN/nano-Al and PETN/nano-AlH3 by ReaxFF simulation

Reactivemoleculardynamicssimulationswith ReaxFF-lg force field parameters were performed on the thermal decompositions of pentaerythritol tetranitrate (PETN), PETN/nano-Al, PETN/nano-AlH3. The unpassivated AlH3 with smaller particle size promote the PETN decomposition greatly. The adsorption of PETN on AlH3 is so strong that PETN deforms seriously and its nitro NO bond ruptures firstly. There are no energy barriers in the thermal decompositions of PETN when AlH3 is added, while the systems release 502.09∼488.18 kcal·mol−1 more energies than pure PETN. The surface passivation of AlH3 greatly reduces the thermal release of PETN/AlH3. The additives increase H2O productions, but decrease N2 and CO2 productions. The total numbers of main gaseous products (H2O, N2 and CO2) increase when AlH3 or passivated AlH3 are added. The prolonged time span of gas producing and energy release are agreeable with the experimental facts.

The unique wick effect and combustion behavior of flax fiber reinforced composites: Experiment and simulation

The mechanical properties of plant fiber reinforced composites present the characteristics of multi-scaled failure due to the presence of hierarchical microstructure, but there is no research concerning the effect of microstructure on the combustion characteristics. In this work, based on single variable principle, three specimens including neat epoxy (EP), carbon fiber reinforced composites (CFRP) and flax fiber reinforced composite (PFRP) were designed to systematically investigate the unique combustion characteristic and wick effect of PFRP via a series of methods. The results show that PFRP exhibits unique combustion characteristic where the heat release rate and smoke production rate show the characteristics of prolonged time span and multi-peaks. Additionally, PFRP expands in the thickness direction during the combustion and the char skeleton can be retained after the combustion. Besides, PFRP also exhibits different wick effect from CFRP where the linear burning rate and the temperature at same position of PFRP is slower and lower, meaning that the interfacial carbonation strategy for efficient flame retardance of traditional fiber reinforced composites is not the optimal solution for PFRP. And the unique wick effect is also verified via the finite element simulation method. The systematic study of PFRP combustion characteristics provides theoretical basis for designing targeted flame-retardant strategies to improve the fire resistance of PFRP.

The response of dual-species bacterial biofilm to 2% and 5% NaOCl mixed with etidronic acid: A laboratory real-time evaluation using optical coherence tomography.

AimThe addition of etidronic acid (HEDP) to sodium hypochlorite (NaOCl) could increase the antibiofilm potency of the irrigant, whilst maintaining the benefits of continuous chelation. Studies conducted so far have shown that mixing HEDP with NaOCl solutions of relatively low concentration does not compromise the antibiofilm efficacy of the irrigant. However, the working lifespan of NaOCl may decrease resulting in a reduction of its antibiofilm efficacy over time (efficiency). In this regard, continuous irrigant replenishment needs to be examined. This study investigated the response of a dual‐species biofilm when challenged with 2% and 5% NaOCl mixed with HEDP for a prolonged timespan and under steady laminar flow.MethodologyDual‐species biofilms comprised of Streptococcus oralis J22 and Actinomyces naeslundii T14V‐J1 were grown on human dentine discs in a constant depth film fermenter (CDFF) for 96 h. Biofilms were treated with 2% and 5% NaOCl, alone or mixed with HEDP. Irrigants were applied under steady laminar flow for 8 min. Biofilm response was evaluated by means of optical coherence tomography (OCT). Biofilm removal, biofilm disruption, rate of biofilm loss and disruption as well as bubble formation were assessed. One‐way anova, Wilcoxon's signed‐rank test and Kruskal–Wallis H test were performed for statistical analysis of the data. The level of significance was set at a ≤.05.ResultsIncreasing NaOCl concentration resulted in increased biofilm removal and disruption, higher rate of biofilm loss and disruption and increased bubble formation. Mixing HEDP with NaOCl caused a delay in the antibiofilm action of the latter, without compromising its antibiofilm efficacy.ConclusionsNaOCl concentration dictates the biofilm response irrespective of the presence of HEDP. The addition of HEDP resulted in a delay in the antibiofilm action of NaOCl. This delay affects the efficiency, but not the efficacy of the irrigant over time.

Effect of Time-Real Marine Environment Exposure on the Mechanical Behavior of FRP Composites

Fiber reinforced polymer (FRP) composites coupons were exposed to real sea environment to assess the influence on the mechanical behavior of composite materials used in the construction of marine structures. Real-life sea environment conditions were opted for instead of the more common simulated and laboratory versions of seawater in the attempt to obtain more realistic structural modeling environmental input design parameters for marine structures. Exposure was performed over prolonged time span instead of the usual accelerated tests. Epoxy and polyester resins, reinforced with glass fibers in three fiber layout configurations, were used to manufacture standardized tensile testing coupons. Mass changes due to seawater absorption, microorganism growth, changes in tensile strength (standard tensile tests), and surface morphology of the coupons were evaluated after 6- and 12-month long periods of submersion in the sea in the Rijeka bay, Croatia. All specimens showed mass increase due to water absorption and growth of attached algae and sea microorganisms. Various levels of reduction in tensile strength, depending on the fiber layout configurations, were observed. Significant changes in the matrix material structure were noticed, effectively producing “voids”. Based on these results, sustainability of FRP composites in marine environment is addressed and discussed.

TCTP overexpression reverses age-associated telomere attrition by upregulating telomerase activity in mouse oocytes.

A prolonged time span between ovulation and fertilization can cause postovulatory aging of oocytes, which impairs oocyte quality and subsequent embryo development. Telomere attrition has long been considered as the primary hallmark of aging or the cause of age-associated diseases. However, the status of telomere and its regulation during postovulatory oocyte aging are poorly understood. Here we found that oocytes experience telomere shortening during postovulatory aging, although they have the capacity to maintain telomere length. However, translationally controlled tumor protein (TCTP) overexpression could reverse age-associated telomere shortening by upregulating telomerase activity in mouse oocytes. Telomere length in mature oocytes gradually decreased with postovulatory aging, which was associated with a marked reduction in TRF1 expression, decreased telomerase activity, and decreased homologous combination (HR)-based alternative lengthening of telomeres (ALT) with a concomitant increase in oxidative stress. Surprisingly, however, overexpression of TCTP led to a remarkable increase in telomere length during postovulatory aging. Notably, neither TRF1 nor BRCA1 level was altered by TCTP overexpression. Moreover, TCTP-mediated telomere lengthening was not blocked by HR inhibition. In striking contrast, telomerase activity, as well as TERT and TERC levels, increased after TCTP overexpression. Importantly, unlike the chromosome-wide distribution of endogenous TCTP, overexpressed TCTP was ectopically localized at telomeres, implying that TCTP overexpression is required to increase telomerase activity. Collectively, our results demonstrate that TCTP prevents telomere attrition during postovulatory aging by upregulating telomerase activity in mouse oocytes.

Nudging Technique In Retail

Changes in consumer behaviour, coupled with shifting purchasing habits, have led to a new setting, one in which the retailers are seeking novel means of keeping potential consumers inside their stores for the maximum duration possible. This prolonged time span contributes to the increased frequency of impulsive actions, thus resulting in greater customer spending. Impulsive buyers are the most crucial target audience for retailers, for they are purely driven by emotion, making decisions without prior preparation or information gathering. Through the grasp of psychological science, behavioural and cognitive functioning, it is possible to discern the factors that make specific retailers and their stores more appealing than others. The main purpose of this paper is to point out a relatively new concept and a technique, called “nudging”, and to showcase the methods of gaining new customers through its utilisation within the Croatian retail market. The nudging technique is not a forceful one, opting to employ imperceptible and subtle means, such as playing certain music, utilising carefully selected scents, colours and lighting within the store, which all serve to improve consumer perception and satisfaction. The retailer can stand out from the competition, precisely by using nudging, which intertwines sensory perception and other psychological factors, incorporating them in the overall store design. For this particular purpose, a survey was conducted among Croatian customers, which examined the presence of specific nudging techniques in retail, as well as their effects on the consumer behaviour. The research results concluded that the Croatian retailers do indeed utilise some nudging techniques which, although perceived by their customers are ultimately left unaware of the impact they have on their respective decision-making process and behaviour

Interpenetrating Hydrogel Networks Enhance Mechanical Stability, Rheological Properties, Release Behavior and Adhesiveness of Platelet-Rich Plasma.

Platelet-rich plasma (PRP) has attracted much attention for the treatment of articular cartilage defects or wounds due to its intrinsic content of growth factors relevant for tissue repair. However, the short residence time of PRP in vivo, due to the action of lytic enzymes, its weak mechanical properties and the consequent short-term release of bioactive factors has restricted its application and efficacy. The present work aimed at designing new formulation strategies for PRP, based on the use of platelet concentrate (PC)-loaded hydrogels or interpenetrating polymer networks, directed at improving mechanical stability and sustaining the release of bioactive growth factors over a prolonged time-span. The interpenetrating hydrogels comprised two polymer networks interlaced on a molecular scale: (a) a first covalent network of thermosensitive and biodegradable vinyl sulfone bearing p(hydroxypropyl methacrylamide-lacate)-polyethylene glycol triblock copolymers, tandem cross-linked by thermal gelation and Michael addition when combined with thiolated hyaluronic acid, and (b) a second network composed of cross-linked fibrin. The PC-loaded hydrogels, instead, was formed only by network (a). All the designed and successfully synthesized formulations greatly increased the stability of PRP in vitro, leading to significant increase in degradation time and storage modulus of PRP gel. The resulting viscoelastic networks showed the ability to controllably release platelet derived growth factor and transforming growth factr β1, and to improve the tissue adhesiveness of PRP. The newly developed hydrogels show great potential for application in the field of wound healing, cartilage repair and beyond.

In vitro postovulatory oocyte aging affects H3K9 trimethylation in two-cell embryos after IVF

BackgroundThe physiological time axis of oocyte maturation comprises highly sensitive processes. A prolonged time span between ovulation and fertilization may impair oocyte developmental competence and subsequent embryo development, possibly due to epigenetic modifications. Since post-translational histone modifications can modify chromatin activity, and trimethylation of H3K9 (H3K9me3) has been shown to increase in the murine oocyte during maturation, here the effect of postovulatory oocyte aging on H3K9me3 was analyzed. MethodsThe competence of murine oocytes which were aged for 2, 4, 6 and 8 h in vitro after oocyte retrieval to develop to the two-cell and blastocyst stage was determined. Degree of H3K9me3 was analyzed in the postovulatory aged oocytes as well as in the resulting two-cell embryos after IVF. ResultsThe current study shows that postovulatory aging of oocytes for up to eight hours after oocyte retrieval exhibited no effect on two-cell embryo and blastocyst rate; however, changes in H3K9me3 in the resulting two-cell embryos were observed. ConclusionProlonged postovulatory oocyte aging leads to epigenetic modifications of H3K9. Such modifications may affect the developmental capacity of embryos at post-implantation developmental stages.

Methuselah's daughters: Paternal age has little effect on offspring number and quality in Cardiocondyla ants.

Male age may directly or indirectly affect the fitness of their female mating partners and their joint progeny. While in some taxa of insects, old males make better mates and fathers, young males excel in others. Males of most social Hymenoptera are relatively short lived and because of testis degeneration have only a limited sperm supply. In contrast, the wingless fighter males of the ant Cardiocondyla obscurior live for several weeks and produce sperm throughout their lives. Wingless males engage in lethal combat with rival males and the winner of such fights can monopolize mating with all female sexuals that emerge in their nests over a prolonged timespan. Here, we investigate if male age has an influence on sperm quality, the queen's lifespan and productivity, and the size and weight of their offspring. Queens mated to one‐week or six‐week‐old males did not differ in life expectancy and offspring production, but the daughters of young males were slightly heavier than those of old males. Our data suggest negligible reproductive senescence of C. obscurior males even at an age, which only few of them reach. This matches the reproductive strategy of Cardiocondyla ants, in which freshly emerging female sexuals rarely have the option to mate with males other than the one present in their natal nest.

Paleomagnetism, magnetic anisotropy and U-Pb baddeleyite geochronology of the early Neoproterozoic Blekinge-Dalarna dolerite dykes, Sweden

Paleogeographic proximity of Baltica and Laurentia in the supercontinent Rodinia has been widely accepted. However, robust paleomagnetic poles are still scarce, hampering quantitative tests of proposed relative positions of the two cratons. A recent paleomagnetic study of the early Neoproterozoic Blekinge-Dalarna dolerite (BDD) dykes in Sweden provided a 946–935 Ma key pole for Baltica, but earlier studies on other BDD dykes discerned large variances in paleomagnetic directions that appeared to indicate more complicated motion of Baltica, or alternatively, unusual geodynamo behavior in early Neoproterozoic time. We present combined paleomagnetic, rock magnetic, magnetic fabric and geochronological studies on BDD dykes in the Dalarna region, southern Sweden. Positive baked-contact and paleosecular variation tests support the reliability of the 951–935 Ma key pole (Plat = −2.6°N, Plon = 239.6°E, A95 = 5.8°, N = 12 dykes); and the ancient magnetic field was likely a stable geocentric axial dipole at that time, based on a positive reversal test. Detailed analysis of the 947 Ma Nornäs dyke, one of the dykes previously showing anomalous directions, suggests a partial viscous remagnetization. Therefore, the observed large variances in nearly coeval BDD dykes are suspected to result from present-day overprints that were not adequately removed in earlier studies. In addition, we obtained a 971 Ma virtual geomagnetic pole (Plat = −27.0°N, Plon = 230.4°E, A95 = 14.9°, N = 4 dykes) for Baltica. Comparing similar-aged poles from Laurentia, we suggest that Baltica and Laurentia drifted together from high to low latitude between 970–960 Ma and 950–935 Ma, and returned back to high latitude by 920–870 Ma. In this scenario, the apparent polar wander paths of Baltica and Laurentia may be more complicated than the previously proposed, solitary Sveconorwegian and Grenville loops. The new U-Pb baddeleyite ages do not support BDD dykes as a giant circumferential swarm generated by a mantle plume, and the prolonged timespan of dyke intrusion is likely associated with the plate boundary forces as causing gravitational extension at the waning stage of the Sveconorwegian orogeny.

Brain-wide glymphatic enhancement and clearance in humans assessed with MRI.

To what extent does the subarachnoid cerebrospinal fluid (CSF) compartment communicate directly with the extravascular compartment of human brain tissue? Interconnection between the subarachnoid CSF compartment and brain perivascular spaces is reported in some animal studies, but with controversy, and in vivo CSF tracer studies in humans are lacking. In the present work, we examined the distribution of a CSF tracer in the human brain by MRI over a prolonged time span. For this, we included a reference cohort, representing close to healthy individuals, and a cohort of patients with dementia and anticipated compromise of CSF circulation (idiopathic normal pressure hydrocephalus). The MRI contrast agent gadobutrol, which is confined to the extravascular brain compartment by the intact blood-brain barrier, was used as a CSF tracer. Standardized T1-weighted MRI scans were performed before and after intrathecal gadobutrol at defined time points, including at 24 hours, 48 hours, and 4 weeks. All MRI scans were aligned and brain regions were segmented using FreeSurfer, and changes in normalized T1 signals over time were quantified as percentage change from baseline. The study provides in vivo evidence of access to all human brain subregions of a substance administered intrathecally. Clearance of the tracer substance was delayed in the dementia cohort. These observations translate previous findings in animal studies into humans and open new prospects concerning intrathecal treatment regimens, extravascular contrast-enhanced MRI, and assessment of brain clearance function.

The impact of tobacco-free pharmacy policies on smoking prevalence

ObjectivesCalifornia and Massachusetts are the only 2 states in the United States with municipalities that have local laws prohibiting the sale of tobacco products by pharmacies. The impacts of the tobacco-free pharmacy laws remain understudied. This study aims to fill this gap by examining the association between tobacco-free pharmacy laws and smoking prevalence among adults over time in California and Massachusetts. DesignThis study used a series of cross-sectional surveys. The data source for this study was the Behavioral Risk Factor Surveillance Survey for each year from 2005 to 2013. SettingThe longitudinal changes in smoking prevalence at the city or county level were estimated and comparisons were made between cities or counties with tobacco-free pharmacy laws and those without the laws. ParticipantsThe participants used to estimate smoking prevalence were representative of adults within California and Massachusetts. InterventionThe implementation of tobacco-free pharmacy laws was considered to be the intervention in this study. Main outcome measuresThe outcome measures were smoking prevalence among adults. Mixed-effects negative binomial models were performed primarily to examine longitudinal changes in outcome measures. ResultsThe prevalence of smoking decreased in both states over time. In Massachusetts, there was a statistically significant decrease in smoking prevalence among cities with tobacco-free pharmacy laws compared with those without such laws. Despite the presence of an 8.6% decrease in prevalence after the implementation of tobacco-free pharmacy laws, this reduction was not statistically significant after controlling for the negative trend in smoking rates overall and other factors. ConclusionThis study evaluated tobacco-free pharmacy laws with regard to the real-world impacts. Our findings highlight the need for future research on the effects of tobacco-free pharmacy laws with a prolonged time span and a comprehensive understanding of the law's implementation and enforcement.

The Clinical Features and Bacteriological Characterizations of Bone and Joint Tuberculosis in China.

Bone and Joint tuberculosis (BJTB) constitutes about 10% of total extra-pulmonary TB cases. Since the BJTB is a paucibacillary condition, there has been no systematic study on the bacterial characterization, especially the epidemiological feature. Here we collected the mycobacterial clinical isolates, analyzed the clinical features and the bacteriological characteristics from 113 BJTB cases reported in China. The mean age of the cases was 40.33 years while most of the patients fell into the 20–29 year age group; local pain was the most common onset symptom of BJTB cases; mean time from symptom onset to BJTB diagnosis was 13.16 months. 31 isolates were defined as drug resistant, including 15 multidrug resistant (MDR) and 2 extensively drug resistant (XDR) isolates according to the drug susceptibility test outcomes; after spoligotyping, 87.6% (99/113) isolates were categorized as Beijing family. In contrast to the isolates from pulmonary tuberculosis patients, here the MIRU-VNTR assay did not find anything significant. A prolonged time span for BJTB diagnosis highlights the requirement of paying further attention to BJTB infection in China. This study provides essential insights into the demographic and microbial characteristics of BJTB cases in China.

P-T-t reconstructions of South Yenisei Ridge metamorphic history (Siberian craton): Petrological consequences and application to the supercontinental cycles

Studies of gneisses from the Yenisei regional shear zone (YRSZ) provide the first evidence for Mesoproterozoic tectonic events in the geologic history of the South Yenisei Ridge and allowed the recognition of several stages of deformation and metamorphism spanning from Late Paleoproterozoic to Vendian. The first stage (~1.73 Ga), corresponding to the period of granulite-amphibolite metamorphism at P = 5.9 kbar and T = 635 °C, marks the final amalgamation of the Siberian craton to the Paleo-Mesoproterozoic Nuna supercontinent. During the second stage, corresponding to a hypothesized breakup of Nuna as a result of crustal extension, these rocks underwent Mesoproterozoic dynamic metamorphism (P = 7.4 kbar and T = 660 °C) with three peaks at 1.54, 1.38, and 1.25 Ga and the formation of high-pressure blastomylonite rocks in shear zones. Late-stage deformations during the Mesoproterozoic tectonic activity in the region, related to the Grenville-age collision processes and assembly of Rodinia, took place at 1.17-1.03 Ga. The latest pulse of dynamic metamorphism (615–600 Ma) marks the final stage of the Neoproterozoic evolution of the Yenisei Ridge, which is associated with the accretion of island-arc terranes to the western margin of the Siberian craton. The overall duration of identified tectonothermal processes within the South Yenisei Ridge during the Riphean (~650 Ma) is correlated with the duration of geodynamic cycles in the supercontinent evolution. A similar succession and style of tectonothermal events in the history of both the southern and the northern parts of the Yenisei Ridge suggest that they evolved synchronously within a single structure over a prolonged time span (1385–600 Ma). New data on coeavl events identified on the western margin of the Siberian craton contradict the hypothesis of a mantle activity lull (from 1.75 to 0.7 Ga) on the southwestern margins of the Siberian craton during the Precambrian. The synchronous sequence and similar style of tectonic events on the periphery of the large Precambrian Laurentia, Baltica, and Siberia cratons suggest their spatial proximity over a prolonged time span (1550–600 Ma). The above conclusion is consistent with the results of modern paleomagnetic reconstructions suggesting that these cratons represented the cores of Nuna and Rodinia within the above time interval.

The history of volcanism on Venus

The history of volcanism on Venus

Morphological analysis of the Hippocampal region of aged rats, role of Clasmatodendrosis

Clasmatodendrosis is a phenomenon first described by Alzheimer in 1910, which was observed in aged nervous system and in the course of neurodegenerative diseases. It consists in the loss of astrocytic distal processes. The occurrence of clasmatodendrosis is frequently associated with an increase of autofluorescent aggregates in different cell types of nervous tissue. In this study we designed a calibrated excitation/emission method of spectral unmixing aimed to discriminate the fluorescence emitted by commercial fluorochrome-conjugated antibodies from the autofluorescent signal, by using confocal microscopy and multiphoton fluorescence lifetime imaging techniques. By this method, the immunolabeled GFAP localization in the CA1 Hippocampal region of aged rats was analyzed. Autofluorescent debris showed a strong positivity to GFAP labeling, suggesting that the detached fragments of clasmatodendrotic astrocytes might take part in the generation of these structures. By 3D confocal analysis we found that these aggregates, were located on neuronal cell surfaces, as well as inside the soma and that, in addition, the presence of autofluorescent aggregates seemed to be related with increased adhesion phenomena among neurons. These data were compared with those obtained in control adult rats and in rats infused with lipopolysaccharide (LPS) in the 4th ventricle to induce a chronic inflammatory state. The presence of autofluorescent aggregates was detected in LPS rats and also in control rats, even if they appeared smaller and with a lesser intensity as compared with the aged rats. These findings suggest that clasmatodendrosis is a process involving the interaction of neurons and astrocytes in a prolonged timespan of life. Its severity increases with aging or under inflammatory and/or neurodegenerative diseases. In conclusion, our results seem to suggest that clasmatodendrosis can affect neuron functionality not only due to a decreased astrocyte activity, but also by direct interaction of the detached astrocytic fragments with neuron somata.

Formation and exposure history of non-magmatic iron meteorites and winonaites: Clues from Sm and W isotopes

New W and Sm isotope measurements for metals and silicates of non-magmatic iron meteorite groups and winonaites are presented and compiled with literature data to assess their exposure history and parent body formation. We report high-precision 182W data for eight IAB metals supplemented by literature data and introduce a method to calculate their zero-exposure values. Our estimate reveals a common radiogenic 182W signature of −2.83±0.03 ε-units for the IAB iron meteorite complex. This suggests metal separation at 5.06 +0.42/−0.41Ma after solar system formation. The refined age estimate for core formation agrees remarkably well with previously published 182Hf–182W ages for silicate melting (4.6 +0.7/−0.6Ma; Schulz et al., 2009) and the formation of winonaites (4.8 +3.1/−2.6Ma; Schulz et al., 2010), which are assumed to be derived from the same parent body. If interpreted in favour of an asteroid-wide (and therefore most likely internal) heat source, these ages correspond to an accretion age for the IAB/winonaite parent body of ∼2Ma after solar system formation. However, metals from ungrouped IAB specimen segregated at significantly different times. Separation of Mundrabilla metals at ∼13Ma after solar system formation can best be explained via impact triggered melt pool formation, a process that could also be responsible for metamorphism of IAB silicates and winonaites between ∼11 and ∼14Ma (Schulz et al., 2009, 2010). 149Sm and 150Sm compositions, indicative of cosmic ray effects, for five IAB silicates reveal a correlation with exposure ages obtained from metal phases and, together with data on three winonaites, provide no compelling evidence for exposure of silicates within near surface regions of the IAB/winonaite parent asteroid.Tungsten isotope compositions of metals from six IIE iron meteorites, measured in this study and reported in the literature, reveal three consecutive metal segregation events at ∼3, ∼13 and ∼28Ma after formation of the solar system. Whereas the oldest event could potentially be explained by internal heat sources, impacts provide the only viable explanation for the latter. A prolonged time-span for thermal events, as deduced from IIE metals, is supported by 182Hf–182W data for two silicate inclusions from Watson (Snyder et al., 2001) and Miles (this study). Samarium isotope data for a silicate inclusion from the Miles meteorite provides no evidence for 2π-exposure.

Transient global cooling at the onset of early Aptian oceanic anoxic event (OAE) 1a

The onset of the early Aptian oceanic anoxic event (OAE) 1a (ca. 120 Ma) coincided with a major perturbation of the carbon cycle, which is reflected in the sedimentary carbon isotope record. Triggering mechanisms, duration, and climatic repercussions of this episode of accelerated organic matter burial remain poorly constrained. Here, we present millennial-scale bulk rock carbon and oxygen isotope data from a marly subtropical intrashelf basin (La Bedoule, southeast France) with unusually high sedimentation rates, which track the onset of OAE1a in unprecedented resolution. Our record reveals that the negative, low-amplitude delta(13)C excursion preceding OAE1a lasted >100 k.y., implying that enhanced volcanic CO(2) emission and/or pulsed methane dissociation over a prolonged time span were instrumental in triggering OAE1a. The main positive carbon isotope shift at the onset of OAE1a, previously regarded as continuous, occurred stepwise over an extended period of >300 k.y. Transient climate cooling during the initial delta(13)C increase probably reflects ephemeral high-latitude glaciation, triggered by changes in radiative forcing and drawdown of atmospheric CO(2).

NEW INSIGHTS ON THE TAPHONOMY OF THE EXCEPTIONAL MAMMALIAN FOSSIL SITES OF CERRO DE LOS BATALLONES (LATE MIOCENE, SPAIN) BASED ON RARE EARTH ELEMENT GEOCHEMISTRY

Cerro de los Batallones fossil sites are distinguished by large and diverse accumulations of Miocene vertebrate fauna. Little taphonomic research has been conducted on these assemblages so far, however. Results of Rare Earth Element (REE) analyses constrain diverse aspects of the taphonomic history undergone by the bones and constitute a starting point for subsequent taphonomic studies. Cerro de los Batallones localities were formed as cavities and seem to be composed of two types of assemblages that differ in their stratigraphic position, internal stratigraphic architecture, taxonomic composition and several taphonomic features. Despite these differences, chemically analyzed bones from the Batallones-1 upper and lower level assemblages exhibit undistinguishable REE patterns both within and between them. This, together with other taphonomic features, indicates that bones are autochthonous and that the depositional context remained constant during the sedimentation of the cavity filling. In addition, REE analyses are a key tool in unveiling the provenance of those fossil bones that could be regarded as allochthonous considering their peculiar macroscopic modifications. Negative Ce anomalies exhibited by isolated fossil bones lead to the proposal that the ponds that existed in the lower level of Batallones-1 were oxic. This inference clarifies the mode of accumulation of individuals in this assemblage: the carcasses did not accumulate massively over a brief period of time but rather they concentrated and, therefore, decayed over a relatively prolonged time span.

Sounding Out Homer: Christopher Logue's Acoustic Homer

This article presents a case study on sound effects in Christopher Logue’s adaptation of Homer’s Iliad, a project that began when Logue adapted Achilles’ fight with the river Scamander from book 21 of the Iliad for BBC radio in 1959. Logue’s Homer has been worked, performed, and reworked for almost fifty years (1959-2005). Albeit the result of accident rather than design, the prolonged time-span for publication has produced a complex publication history, with Logue’s Homer poems circulating in different print versions and simultaneously existing as audio recordings (both on LP and CD) and live performances. Within the poems themselves, the stress on sound and music suggest that these performances should inform the meaning of the printed text, leading to a complex interdependence between the written and spoken word. 1