Oxygen isotope values from biogenic apatie (conodont elements and fish teeth) from the Lower Triassic Mianwali Formation (Salt Range, Pakistan)

Recovery from the end-Permian mass extinction is frequently described as delayed, with complex ecological communities typically not found in the fossil record until the Middle Triassic epoch. However, the taxonomic diversity of a number of marine groups, ranging from ammonoids to benthic foraminifera, peaked rapidly in the Early Triassic. These variations in biodiversity occur amidst pronounced excursions in the carbon isotope record, which are compatible with episodes of massive CO2 outgassing from the Siberian Large Igneous Province. Here we present a high-resolution Early Triassic temperature record based on the oxygen isotope composition of pristine apatite from fossil conodonts. Our reconstruction shows that the beginning of the Smithian substage of the Early Triassic was marked by a cooler climate, followed by an interval of warmth lasting until the Spathian substage boundary. Cooler conditions resumed in the Spathian. We find the greatest increases in taxonomic diversity during the cooler phases of the early Smithian and early Spathian. In contrast, a period of extreme warmth in the middle and late Smithian was associated with floral ecological change and high faunal taxonomic turnover in the ocean. We suggest that climate upheaval and carbon-cycle perturbations due to volcanic outgassing were important drivers of Early Triassic biotic recovery.

Electrical resistivity, formation factors, and sound velocity at DSDP Holes 75-530A and 75-530B

From 0 to 277 m at Site 530 are found Holocene to Miocene diatom ooze, nannofossil ooze, marl, clay, and debrisflow deposits; from 277 to 467 m are Miocene to Oligocene mud; from 467 to 1103 m are Eocene to late Albian Cenomanian interbedded mudstone, marlstone, chalk, clastic limestone, sandstone, and black shale in the lower portion; from 1103 to 1121 m are basalts. In the interval from 0 to 467 m, in Holocene to Oligocene pelagic oozes, marl, clay, debris flows, and mud, velocities are 1.5 to 1.8 km/s; below 200 m velocities increase irregularly with increasing depth. From 0 to 100 m, in Holocene to Pleistocene diatom and nannofossil oozes (excluding debris flows), velocities are approximately equivalent to that of the interstitial seawater, and thus acoustic reflections in the upper 100 m are primarily caused by variations in density and porosity. Below 100 or 200 m, acoustic reflections are caused by variations in both velocity and density. From 100 to 467 m, in Miocene-Oligocene nannofossil ooze, clay, marl, debris flows, and mud, acoustic anisotropy irregularly increases to 10%, with 2 to 5% being typical. From 467 to 1103 m in Paleocene to late Albian Cenomanian interbedded mudstone, marlstone, chalk, clastic limestone, and black shale in the lower portion of the hole, velocities range from 1.6 to 5.48 km/s, and acoustic anisotropies are as great as 47% (1.0 km/s) faster horizontally. Mudstone and uncemented sandstone have anisotropies which irregularly increase with increasing depth from 5 to 10% (0.2 km/s). Calcareous mudstones have the greatest anisotropies, typically 35% (0.6 km/s). Below 1103 m, basalt velocities ranged from 4.68 to 4.98 km/s. A typical value is about 4.8 km/s. In situ velocities are calculated from velocity data obtained in the laboratory. These are corrected for in situ temperature, hydrostatic pressure, and porosity rebound (expansion when the overburden pressure is released). These corrections do not include rigidity variations caused by overburden pressures. These corrections affect semiconsolidated sedimentary rocks the most (up to 0.25 km/s faster). These laboratory velocities appear to be greater than the velocities from the sonic log. Reflection coefficients derived from the laboratory data, in general, agree with the major features on the seismic profiles. These indicate more potential reflectors than indicated from the reflection coefficients derived using the Gearhart-Owen Sonic Log from 625 to 940 m, because the Sonic Log data average thin beds. Porosity-density data versus depth for mud, mudstone, and pelagic oozes agree with data for similar sediments as summarized in Hamilton (1976). At depths of about 400 m and about 850 m are zones of relatively higher porosity mudstones, which may suggest anomalously high pore pressure; however, they are more probably caused by variations in grain-size distribution and lithology. Electrical resistivity (horizontal) from 625 to 950 m ranged from about 1.0 to 4.0 ohm-m, in Maestrichtian to Santonian- Coniacian mudstone, marlstone, chalk, clastic limestone, and sandstone. An interstitial-water resistivity curve did not indicate any unexpected lithology or unusual fluid or gas in the pores of the rock. These logs were above the black shale beds. From 0 to 100 m at Sites 530 and 532, the vane shear strength on undisturbed samples of Holocene-Pleistocene diatom and nannofossil ooze uniformly increases from about 80 g/cm**2 to about 800 g/cm**2. From 100 to 300 m, vane shear strength of Pleistocene-Miocene nannofossil ooze, clay, and marl are irregular versus depth with a range of 500 to 2300 g/cm**2; and at Site 532 the vane shear strength appears to decrease irregularly and slightly with increasing depth (gassy zone). Vane shear strength values of gassy samples may not be valid, for the samples may be disturbed as gas evolves, and the sediments may not be gassy at in situ depths.

Geochemistry of the Kimmeridge Clay Formation, Dorset Coast

The Kimmeridge Clay Formation (KCF) and its equivalents worldwide represent one of the most prolonged periods of organic carbon accumulation of the Mesozoic. In this study, we use the molybdenum (Mo) stable isotope system in conjunction with a range of trace metal paleoredox proxies to assess how seawater redox varied both locally and globally during the deposition of the KCF. Facies with lower organic carbon contents (TOC 1-7 wt %) were deposited under mildly reducing (suboxic) conditions, while organic-rich facies (TOC >7 wt %) accumulated under more strongly reducing (anoxic or euxinic) local conditions. Trace metal abundances are closely linked to TOC content, suggesting that the intensity of reducing conditions varied repeatedly during the deposition of the KCF and may have been related to orbitally controlled climate changes. Long-term variations in d98/95Mo are associated with the formation of organic-rich intervals and are related to third-order fluctuations in relative sea level. Differences in the mean d98/95Mo composition of the organic-rich intervals suggest that the global distribution of reducing conditions was more extensive during the deposition of the Pectinatites wheatleyensis and lower Pectinatites hudlestoni zones than during the deposition of the upper Pectinatites hudlestoni and Pectinatites pectinatus zones. The global extent of reducing conditions during the Kimmerigidan was greater than today but was less widespread than during the Toarcian (Early Jurassic) oceanic anoxic event. This study also demonstrates that the Mo isotope system in Jurassic seawater responded to changes in redox conditions in a manner consistent with its behavior in present-day sedimentary environments.

Mechanics of raceway hysteresis in a packed bed

When a gas is introduced at high velocity through a nozzle into a packed bed, it creates a raceway in the packed bed. It has been found that the raceway size is larger when it is formed by decreasing the gas velocity from its highest value than when it is formed by increasing the gas velocity. This phenomenon is known as raceway hysteresis. A hypothesis has been oroposed to explain the hysteresis phenomenon based on a force-balance approach which includes frictional, bed-weight, and pressure forces. According to this hypothesis, the frictional force acts in different directions when the raceway is expanding and contracting. In this article, the entire packed bed has been divided into radial and Cartesian co-ordinate systems, and the forces acting on the raceway have been solved analytically for a simplified one-dimensional case. Based on the force-balance approach, a general equation has been obtained to predict the diameter of the raceway for increasing And decreasing velocities. A reasonable agreement has been found between the theoretical predictions and experimental observations. The model has also been compared with published experimental and plant data. The hysteresis mechanism in the packed beds can be described reasonably by taking into consideration the direction of frictional forces for the increasing- and decreasin-velocity cases. The effects of the particleshape factor and void fraction on the raceway hysteresis are examined.

Coke formation in the oxidative dehydrogenation of ethylbenzene to styrene by TEOM

A packed bed microbalance reactor setup (TEOM-GC) is used to investigate the formation of coke as a function of time-on-stream on γ-Al2O3 and 3P/SiO2 catalyst samples under different conditions for the ODH reaction of ethylbenzene to styrene. All samples show a linear correlation of the styrene selectivity and yield with the initial coverage of coke. The COX production increases with the coverage of coke. On the 3 wt% P/SiO2 sample, the initial coke build-up is slow and the coke deposition rate increases with time. On alumina-based catalyst samples, a fast initial coke build-up takes place, decreasing with time-on-stream, but the amount of coke does not stabilize. A higher O2 : EB feed ratio results in more coke, and a higher temperature results in less coke. This coking behaviour of Al2O3 can be described by existing "monolayer-multilayer" models. Further, the coverage of coke on the catalyst varies with the position in the bed. For maximal styrene selectivity, the optimal coverage of coke should be sufficient to convert all O2, but as low as possible to prevent selectivity loss by COX production. This is in favour of high temperature and low O2 : EB feed ratios. The optimal coke coverage depends in a complex way on all the parameters: temperature, the O2 : EB feed ratio, reactant concentrations, and the type of starting material. This journal is

Sedimentology of a Middle Jurassic Base-of-Slope environment, Cutri Formation, Mallorca

The Cutri Formation’s, type location, exposed in the NW of Mallorca, Spain has previously been described by Álvaro et al., (1989) and further interpreted by Abbots (1989) unpublished PhD thesis as a base-of-slope carbonate apron. Incorporating new field and laboratory analysis this paper enhances this interpretation. From this analysis, it can be shown without reasonable doubt that the Cutri Formation was deposited in a carbonate base-of-slope environment on the palaeowindward side of a Mid-Jurassic Tethyan platform. Key evidence such as laterally extensive exposures, abundant deposits of calciturbidtes and debris flows amongst hemipelagic deposits strongly support this interpretation.

Culturable Bacterial Diversity From A Feed Water Of A Reverse Osmosis System, Evaluation Of Biofilm Formation And Biocontrol Using Phages.

Biofilm formation on reverse osmosis (RO) systems represents a drawback in the application of this technology by different industries, including oil refineries. In RO systems the feed water maybe a source of microbial contamination and thus contributes for the formation of biofilm and consequent biofouling. In this study the planktonic culturable bacterial community was characterized from a feed water of a RO system and their capacities were evaluated to form biofilm in vitro. Bacterial motility and biofilm control were also analysed using phages. As results, diverse Protobacteria, Actinobacteria and Bacteroidetes were identified. Alphaproteobacteria was the predominant group and Brevundimonas, Pseudomonas and Mycobacterium the most abundant genera. Among the 30 isolates, 11 showed at least one type of motility and 11 were classified as good biofilm formers. Additionally, the influence of non-specific bacteriophage in the bacterial biofilms formed in vitro was investigated by action of phages enzymes or phage infection. The vB_AspP-UFV1 (Podoviridae) interfered in biofilm formation of most tested bacteria and may represent a good alternative in biofilm control. These findings provide important information about the bacterial community from the feed water of a RO system that may be used for the development of strategies for biofilm prevention and control in such systems.

Discovery Of A Rare Pterosaur Bone Bed In A Cretaceous Desert With Insights On Ontogeny And Behavior Of Flying Reptiles.

A pterosaur bone bed with at least 47 individuals (wing spans: 0.65-2.35 m) of a new species is reported from southern Brazil from an interdunal lake deposit of a Cretaceous desert, shedding new light on several biological aspects of those flying reptiles. The material represents a new pterosaur, Caiuajara dobruskii gen. et sp. nov., that is the southermost occurrence of the edentulous clade Tapejaridae (Tapejarinae, Pterodactyloidea) recovered so far. Caiuajara dobruskii differs from all other members of this clade in several cranial features, including the presence of a ventral sagittal bony expansion projected inside the nasoantorbital fenestra, which is formed by the premaxillae; and features of the lower jaw, like a marked rounded depression in the occlusal concavity of the dentary. Ontogenetic variation of Caiuajara dobruskii is mainly reflected in the size and inclination of the premaxillary crest, changing from small and inclined (∼ 115°) in juveniles to large and steep (∼ 90°) in adults. No particular ontogenetic features are observed in postcranial elements. The available information suggests that this species was gregarious, living in colonies, and most likely precocial, being able to fly at a very young age, which might have been a general trend for at least derived pterosaurs.

Epiretinal Membrane Formation Associated With Idiopathic Macular Telangiectasia: Case Report.

A 46-year-old woman complained of blurred and distorted vision in both eyes. Ophthalmic examination showed that visual acuity was 20/200 for the right eye and counting fingers left eye. Fundoscopy revealed perimacular hemorrhages, aneurismal dilatation of the vessels in the posterior pole, and a white and elevated lesion adjacent to vascular changes. We report a case of idiopathic macular telangiectasia and epiretinal membrane that occurs concomitantly. To our knowledge, this is the first report that describes an association between idiopathic macular telangiectasia and epiretinal membrane formation.

Prominent Role Of Platelets In The Formation Of Circulating Neutrophil-red Cell Heterocellular Aggregates In Sickle Cell Anemia.

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G-quadruplex Formation Enhances Splicing Efficiency Of Pax9 Intron 1.

G-quadruplexes are secondary structures present in DNA and RNA molecules, which are formed by stacking of G-quartets (i.e., interaction of four guanines (G-tracts) bounded by Hoogsteen hydrogen bonding). Human PAX9 intron 1 has a putative G-quadruplex-forming region located near exon 1, which is present in all known sequenced placental mammals. Using circular dichroism (CD) analysis and CD melting, we showed that these sequences are able to form highly stable quadruplex structures. Due to the proximity of the quadruplex structure to exon-intron boundary, we used a validated double-reporter splicing assay and qPCR to analyze its role on splicing efficiency. The human quadruplex was shown to have a key role on splicing efficiency of PAX9 intron 1, as a mutation that abolished quadruplex formation decreased dramatically the splicing efficiency of human PAX9 intron 1. The less stable, rat quadruplex had a less efficient splicing when compared to human sequences. Additionally, the treatment with 360A, a strong ligand that stabilizes quadruplex structures, further increased splicing efficiency of human PAX9 intron 1. Altogether, these results provide evidences that G-quadruplex structures are involved in splicing efficiency of PAX9 intron 1.

Flavoring agents present in a dentifrice can modify volatile sulphur compounds (VSCs) formation in morning bad breath

This study aimed to evaluate the effects of a flavor-containing dentifrice on the formation of volatile sulphur compounds (VSCs) in morning bad breath. A two-step, blinded, crossover, randomized study was carried out in 50 dental students with a healthy periodontium divided into two experimental groups: flavor-containing dentifrice (test) and non-flavor-containing dentifrice (control). The volunteers received the designated dentifrice and a new toothbrush for a 3 X/day brushing regimen for 2 periods of 30 days. A seven-day washout interval was used between the periods. The assessed parameters were: plaque index (PI), gingival index (GI), organoleptic breath scores (ORG), VSC levels (as measured by a portable sulphide monitor) before (H1) and after (H2) cleaning of the tongue, tongue coating (TC) wet weight and BANA test from TC samples. The intra-group analysis showed a decrease in ORG, from 3 to 2, after 30 days for the test group (p < 0.05). The inter-group analysis showed lower values in ORG, H1 and H2 for the test group (p < 0.05). There was no difference between the amount of TC between groups and the presence of flavor also did not interfere in the BANA results between groups (p > 0.05). These findings suggest that a flavor-containing dentifrice seems to prevent VSCs formation in morning bad breath regardless of the amount of TC in periodontally healthy subjects.

Endodontic treatment of dental formation anomalies

PURPOSE: Dental fusion is defined as the union of two dental germs at some stage of their development. The aim of this article is to report the endodontic treatment of two clinical cases of dental fusion. CASE DESCRIPTION: In the first case, the patient was referred by an orthodontist for endodontic treatment of tooth 12, which was fused to 13. Surgical separation and later replacement of the involved elements in the dental arch was indicated. In the second case, the patient sought dental attendance due to spontaneous pain. In the radiographic exam, gemination in tooth 11 and fusion of 21 with a supernumerary tooth was observed. The fused teeth were endodontically treated, and patients were referred to other dental specialties to reestablish esthetics and function. CONCLUSION: The dentist must be able to diagnose, differentiate and treat these dental anomalies adequately, with the goal of maintaining patients' oral health.

Seasonal variation of epiphytic hydroids (Cnidaria: Hydrozoa) associated to a subtropical Sargassum cymosum (Phaeophyta: Fucales) bed

Hydroids are broadly reported in epiphytic associations from different localities showing marked seasonal cycles. Studies have shown that the factors behind these seasonal differences in hydroid richness and abundance may vary significantly according to the area of study. Seasonal differences in epiphytic hydroid cover and richness were evaluated in a Sargassum cymosum C. Agardh bed from Lázaro beach, at Ubatuba, Brazil. Significant seasonal differences were found in total hydroid cover, but not in species richness. Hydroid cover increased from March (early fall) to February (summer). Most of this pattern was caused by two of the most abundant species: Aglaophenia latecarinata Allman, 1877 and Orthopyxis sargassicola (Nutting, 1915). Hydroid richness seems to be related to S. cymosum size but not directly to its biomass. The seasonal differences in hydroid richness and algal cover are shown to be similar to other works in the study region and in the Mediterranean. Seasonal recruitment of hydroid species larvae may be responsible for their seasonal differences in algal cover, although other factors such as grazing activity of gammarid amphipods on S. cymosum must be taken into account.