168 research outputs found

    Response of deep-water agglutinated foraminifera to dysoxic conditions in the California Borderland basins

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    Analysis of agglutinated benthic foraminifera from surface samples collected in the San Pedro and Santa Catalina Basins reveals a predictable relationship between the proportions of morphogroups with decreasing bottom water oxygen levels and with the TOC content of the surficial sediment. Living (Rose Bengal stained) foraminiferal faunas from dysaerobic environments display low diversity and high dominance, suggesting stressed conditions. There is an inverse relationship between oxygen and the relative abundance of deep infaunal morphogroups. Samples collected from shallow stations above the oxygen minimum zone are comprised of epifaunal and shallow infaunal morphotypes. At intermediate depths (~500 m), there is a peak in the abundance of suspension-feeding and "climbing" forms (watchglass-shaped trochamminids attached to Rhabdammina). Specimens from intermediate stations display the largest overall size. Deeper in the San Pedro Basin the living fauna is dominated by a small, flattened, tapered, species that is interpreted as having a deep infaunal microhabitat. In the dysaerobic environments off California the greatest degree of faunal change occurs when bottom water dissolved oxygen values drop from 0.5 ml/l to 0.2 ml/l. The effect of TOC content on the benthic fauna is demonstrated at two stations from the same depth in the San Pedro Basin. The station with the higher TOC content (4.2% vs. 2.9%) contains greater proportions of the small, deep infaunal morphotype. These faunal changes may be attributed to differences in the depth of the oxygenated zone within the sediment surface layer. Agglutinated faunas from areas that experience seasonal anoxia are comprised of a large proportion of opportunistic forms such as Reophax and Psammosphaera. These are the same taxa that colonised abiotic sediment trays in a recolonisation experiment in the Panama Basin. This study further demonstrates that agglutinated foraminiferal morphotypes respond in a similar manner to calcareous benthic foraminifera in dysaerobic environments

    Plectoeratidus subarcticus, n.gen., n.sp., a new agglutinated foraminifer from the Upper Cretaceous of the western Barents Sea

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    We describe the new foraminiferal genus and species Plectoeratidus subarcticus n.gen. n.sp., from the Upper Cretaceous deep-water deposits of the Kviting and Kveite formations in the western Barents Sea. The genus is characterised by its planispiral-biserial-uniserial chamber arrangement, terminal aperture and lateral compression. The biometric analysis of test ontogenesis has been applied to document its dimorphism attributed to megalospheric and microspheric generations. This taxon may represent an evolutionary transition between the Cretaceous genera Spiroplectammina or Bolivinopsis and the Cenozoic genus Eratidus. The taxon appears to be endemic to the flysch-type agglutinated foraminiferal assemblages in the Norwegian Sea area

    Regional requirements for Dishevelled signaling during Xenopus gastrulation: separable effects on blastopore closure, mesendoderm internalization and archenteron formation

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    During amphibian gastrulation, the embryo is transformed by the combined actions of several different tissues. Paradoxically, many of these morphogenetic processes can occur autonomously in tissue explants, yet the tissues in intact embryos must interact and be coordinated with one another in order to accomplish the major goals of gastrulation: closure of the blastopore to bring the endoderm and mesoderm fully inside the ectoderm, and generation of the archenteron. Here, we present high-resolution 3D digital datasets of frog gastrulae, and morphometrics that allow simultaneous assessment of the progress of convergent extension, blastopore closure and archenteron formation in a single embryo. To examine how the diverse morphogenetic engines work together to accomplish gastrulation, we combined these tools with time-lapse analysis of gastrulation, and examined both wild-type embryos and embryos in which gastrulation was disrupted by the manipulation of Dishevelled (Xdsh) signaling. Remarkably, although inhibition of Xdsh signaling disrupted both convergent extension and blastopore closure, mesendoderm internalization proceeded very effectively in these embryos. In addition, much of archenteron elongation was found to be independent of Xdsh signaling, especially during the second half of gastrulation. Finally, even in normal embryos, we found a surprising degree of dissociability between the various morphogenetic processes that occur during gastrulation. Together, these data highlight the central role of PCP signaling in governing distinct events of Xenopus gastrulation, and suggest that the loose relationship between morphogenetic processes may have facilitated the evolution of the wide variety of gastrulation mechanisms seen in different amphibian species

    Brain Differences in the Prefrontal Cortex, Amygdala, and Hippocampus in Youth with Congenital Adrenal Hyperplasia

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    Context: Classical Congenital Adrenal Hyperplasia (CAH) due to 21-hydroxylase deficiency results in hormone imbalances present both prenatally and postnatally that may impact the developing brain. Objective: To characterize gray matter morphology in the prefrontal cortex and subregion volumes of the amygdala and hippocampus in youth with CAH, compared to controls. Design: A cross-sectional study of 27 CAH youth (16 female; 12.6 ± 3.4 year) and 35 typically developing, healthy controls (20 female; 13.0 ± 2.8 year) with 3-T magnetic resonance imaging scans. Brain volumes of interest included bilateral prefrontal cortex, and nine amygdala and six hippocampal subregions. Between-subject effects of group (CAH vs control) and sex, and their interaction (group-by-sex) on brain volumes were studied, while controlling for intracranial volume (ICV) and group differences in body mass index and bone age. Results: CAH youth had smaller ICV and increased cerebrospinal fluid volume compared to controls. In fully-adjusted models, CAH youth had smaller bilateral, superior and caudal middle frontal volumes, and smaller left lateral orbito-frontal volumes compared to controls. Medial temporal lobe analyses revealed the left hippocampus was smaller in fully-adjusted models. CAH youth also had significantly smaller lateral nucleus of the amygdala and hippocampal subiculum and CA1 subregions. Conclusions: This study replicates previous findings of smaller medial temporal lobe volumes in CAH patients, and suggests that lateral nucleus of the amygdala, as well as subiculum and subfield CA1 of the hippocampus are particularly affected within the medial temporal lobes in CAH youth

    Spatial and frequency domain effects of defects in 1D photonic crystal

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    The aim of this paper is to present the analysis of influence of defects in 1D photonic crystal (PC) on the density of states and simultaneously spontaneous emission, in both spatial and frequency domains. In our investigations we use an analytic model of 1D PC with defects. Our analysis reveals how presence of a defect causes a defect mode to appear. We show that a defect in 1D PC has local character, being negligible in regions of PC situated far from the defected elementary cell. We also analyze the effect of multiple defects, which lead to photonic band gap splitting.Comment: presented at International Workshop on Physics of Photonic Crystals and Metamaterials, Brussels, Belgium, 12-13.06.200

    Brain Differences in the Prefrontal Cortex, Amygdala, and Hippocampus in Youth with Congenital Adrenal Hyperplasia

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    Context: Classical Congenital Adrenal Hyperplasia (CAH) due to 21-hydroxylase deficiency results in hormone imbalances present both prenatally and postnatally that may impact the developing brain. Objective: To characterize gray matter morphology in the prefrontal cortex and subregion volumes of the amygdala and hippocampus in youth with CAH, compared to controls. Design: A cross-sectional study of 27 CAH youth (16 female; 12.6 ± 3.4 year) and 35 typically developing, healthy controls (20 female; 13.0 ± 2.8 year) with 3-T magnetic resonance imaging scans. Brain volumes of interest included bilateral prefrontal cortex, and nine amygdala and six hippocampal subregions. Between-subject effects of group (CAH vs control) and sex, and their interaction (group-by-sex) on brain volumes were studied, while controlling for intracranial volume (ICV) and group differences in body mass index and bone age. Results: CAH youth had smaller ICV and increased cerebrospinal fluid volume compared to controls. In fully-adjusted models, CAH youth had smaller bilateral, superior and caudal middle frontal volumes, and smaller left lateral orbito-frontal volumes compared to controls. Medial temporal lobe analyses revealed the left hippocampus was smaller in fully-adjusted models. CAH youth also had significantly smaller lateral nucleus of the amygdala and hippocampal subiculum and CA1 subregions. Conclusions: This study replicates previous findings of smaller medial temporal lobe volumes in CAH patients, and suggests that lateral nucleus of the amygdala, as well as subiculum and subfield CA1 of the hippocampus are particularly affected within the medial temporal lobes in CAH youth

    Triassic and Jurassic possible planktonic foraminifera and the assemblages recovered from the Ogrodzieniec Glauconitic Marls Formation (uppermost Callovian and lowermost Oxfordian, Jurassic) of the Polish Basin

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    Abstract. In the 1960s and 1970s Werner Fuchs of the Austrian Geological Survey (Vienna) described a significant number of new foraminiferal taxa that he considered ancestral to the planktonic foraminifera. All these taxa are well-curated in the collections of the Austrian Geological Survey and have been studied by one of us (Malcolm B. Hart). Some of these taxa, from the Triassic and lowermost Jurassic strata of Austria and northern Italy, are poorly preserved, possibly the result of having an original aragonitic wall structure. None of these taxa possess characters which give the appearance of a planktonic mode of life, although some of them (e.g. Oberhauserella, Praegubkinella) may well have been ancestral to the holoplanktonic foraminifera that appeared in the Toarcian and younger strata. Other taxa in the collections of the Austrian Geological Survey (part of GeoSphere Austria), from the Jurassic of Poland, are preserved as glauconitic steinkerns and are either unidentifiable as foraminifera or suspect in terms of their stratigraphical and evolutionary significance

    Antibacterial, antioxidant and anti-proliferative properties and zinc content of five south Portugal herbs

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    Context: Crataegus monogyna L. (Rosaceae) (CM), Equisetum telmateia L. (Equisataceae) (ET), Geranium purpureum Vil. (Geraniaceae) (GP), Mentha suaveolens Ehrh. (Lamiaceae) (MS), and Lavandula stoechas L. spp. luisieri (Lamiaceae) (LS) are all medicinal. Objective: To evaluate the antioxidant, antiproliferative and antimicrobial activities of plant extracts and quantify individual phenolics and zinc. Material and methods: Aerial part extracts were prepared with water (W), ethanol (E) and an 80% mixture (80EW). Antioxidant activity was measured with TAA, FRAP and RP methods. Phenolics were quantified with a HPLC. Zinc was quantified using voltammetry. Antibacterial activity (after 48 h) was tested using Enterococcus faecalis, Bacillus cereus, Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Listeria monocytogenes. Antiproliferative activity (after 24 h) was tested using HEP G2 cells and fibroblasts. Results: Solvents influenced results; the best were E and 80EW. GP had the highest antioxidant activity (TAA and FRAP of 536.90mg AAE/g dw and 783.48mg TE/g dw, respectively). CM had the highest zinc concentration (37.21 mg/kg) and phenolic variety, with neochlorogenic acid as the most abundant (92.91 mg/100 g dw). LS was rich in rosmarinic acid (301.71 mg/100 g dw). GP and LS inhibited the most microorganisms: B. cereus, E. coli and S. aureus. GP also inhibited E. faecalis. CM had the lowest MIC: 5830 mu g/mL. The antibacterial activity is explained by the phenolics present. LS and CM showed the most significant anti-proliferative activity, which is explained by their zinc content. Conclusion: The most promising plants for further studies are CM, LS and GP.FCT, Fundacao para a Ciencia e a Tecnologia of Portugal [SFRH/BSA/139/2014

    Restructuring of amygdala subregion apportion across adolescence

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    Total amygdala volumes develop in association with sex and puberty, and postmortem studies find neuronal numbers increase in a nuclei specific fashion across development. Thus, amygdala subregions and composition may evolve with age. Our goal was to examine if amygdala subregion absolute volumes and/or relative proportion varies as a function of age, sex, or puberty in a large sample of typically developing adolescents (N = 408, 43 % female, 10–17 years). Utilizing the in vivo CIT168 atlas, we quantified 9 subregions and implemented Generalized Additive Mixed Models to capture potential non-linear associations with age and pubertal status between sexes. Only males showed significant age associations with the basolateral ventral and paralaminar subdivision (BLVPL), central nucleus (CEN), and amygdala transition area (ATA). Again, only males showed relative differences in the proportion of the BLVPL, CEN, ATA, along with lateral (LA) and amygdalostriatal transition area (ASTA), with age. Using a best-fit modeling approach, age, and not puberty, was found to drive these associations. The results suggest that amygdala subregions show unique variations with age in males across adolescence. Future research is warranted to determine if our findings may contribute to sex differences in mental health that emerge across adolescence

    Triassic and Jurassic possible planktonic foraminifera and the assemblages recovered from the Ogrodzieniec Glauconitic Marls Formation (uppermost Callovian and lowermost Oxfordian, Jurassic) of the Polish Basin

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    In the 1960s and 1970s Werner Fuchs of the Austrian Geological Survey (Vienna) described a significant number of new foraminiferal taxa that he considered ancestral to the planktonic foraminifera. All these taxa are well-curated in the collections of the Austrian Geological Survey and have been studied by one of us (Malcolm B. Hart). Some of these taxa, from the Triassic and lowermost Jurassic strata of Austria and northern Italy, are poorly preserved, possibly the result of having an original aragonitic wall structure. None of these taxa possess characters which give the appearance of a planktonic mode of life, although some of them (e.g. Oberhauserella, Praegubkinella) may well have been ancestral to the holoplanktonic foraminifera that appeared in the Toarcian and younger strata. Other taxa in the collections of the Austrian Geological Survey (part of GeoSphere Austria), from the Jurassic of Poland, are preserved as glauconitic steinkerns and are either unidentifiable as foraminifera or suspect in terms of their stratigraphical and evolutionary significance.</p
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