4,631 research outputs found

    Factors limiting the establishment of canopy-forming algae on artificial structures

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    Macroalgal canopies are important ecosystem engineers, contributing to coastal productivity and supporting a rich assemblage of associated flora and fauna. However, they are often absent from infrastructures such as coastal defences and there has been a worldwide decline in their distribution in urbanised coastal areas. The macroalga Fucus spiralis is the only high-shore canopy forming species present in the Azores. It is widely distributed in the archipelago but is never found on coastal infrastructures. Here we evaluate factors that may potentially limit its establishment on artificial structures. A number of observational and manipulative experiments were used to test the hypotheses that: (i) limited-dispersal ability limits the colonisation of new plants onto artificial structures, (ii) vertical substratum slope negatively influences the survivorship of recruits, and (iii) vertical substratum slope also negatively influences the survivorship and fitness of adults. Results showed that the limited dispersal from adult plants may be a more important factor than slope in limiting the species ability to colonise coastal infrastructures, since the vertical substratum slope does not affect its fitness or survivorship.European Regional Development Fund (ERDF); COMPETE - Operational Competitiveness Programme; FCT - Foundation for Science and Technology; cE3c funding. GMM was supported by a postdoctoral grant awarded by FCT (SFRH/BDP/63040/2009). ACLP was funded by a FRCT research grant M3.1.5/F/098/2012. Support was also provided by CIRN/UAc (Centre of Natural Resources of University of the Azores).info:eu-repo/semantics/publishedVersio

    Effects of co-treatment of Rauwolfia vomitoria and Gongronema latifolium on neurobehaviour and the neurohistology of the cerebral cortex in mice

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    Rauwolfia vomitoria and Gongronema latifolium are medicinal plants with antioxidant, antidiabetic and analgesic properties among others. R. vomitoria is reported to possess adverse neural effects, which G. latifolium has shown the potential to address. This study therefore investigated the effects of co-treatment of R. vomitoria and G. latifolium on the neurobehaviour and histology of the cerebral cortex of female mice. Twenty female Wistar mice were divided into 4 groups (A, B, C and D). Group A designated as the control received 0.4 mL of 20 % Tween, while groups B, C and D received oral doses of 150 mg/kg of R. vomitoria (RV), 200 mg/kg of G. latifolium (GL) and a combination of 150 mg/kg of R. vomitoria and 200 mg/kg of G. latifolium (RV+GL), respectively for seven days. Light and dark field behaviour test was carried out on day 8 and the animals were immediately sacrificed. Their brains were excised and routinely processed by haematoxylin and eosin method. There was no difference in body and brain weights, and the behavioural parameters. Cellular cyto-architecture showed higher glial population with no apparent histopathology. The cellular population was higher (p<0.0001) in the RV and RV+GL groups, while the GL group was less (p<0.0001) populated all compared to the control.In conclusion, the reported treatment regimes, RV administered singly and in combination with GL may not affect some neurobehavioural activities, but may result in cellular increase in the cerebral cortex.KEY WORDS: Rauwolfia vomitoria; Gongronema latifolium; Cerebral cortex; Mic

    Magnetar-like X-ray Bursts from an Anomalous X-ray Pulsar

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    Anomalous X-ray Pulsars (AXPs) are a class of rare X-ray pulsars whose energy source has been perplexing for some 20 years. Unlike other, better understood X-ray pulsars, AXPs cannot be powered by rotation or by accretion from a binary companion, hence the designation ``anomalous.'' AXP rotational and radiative properties are strikingly similar to those of another class of exotic objects, the Soft Gamma Repeaters (SGRs). However, the defining property of SGRs, namely their low-energy gamma-ray and X-ray bursts, have heretofore not been seen in AXPs. SGRs are thought to be ``magnetars,'' young neutron stars powered by the decay of an ultra-high magnetic field. The suggestion that AXPs are magnetars has been controversial. Here we report the discovery, from the direction of AXP 1E 1048-5937, of two X-ray bursts that have many properties similar to those of SGR bursts. These events imply a close relationship between AXPs and SGRs, with both being magnetars.Comment: 14 pages, 2 figures, accepted for publication in Nature. Note: The content of this paper is embargoed until 1900 hrs London time / 1400 US Eastern Time on Sept 1

    Green Health in Guatemala - How can we build mutual trust and partnerships for developing local medicines’ evidence-base and potential?

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    The implementation of access and benefit-sharing (ABS) protocols and especially the Nagoya Protocol has created new hurdles for collaborations around Indigenous Traditional Knowledge and international collaborations. Overall, these frameworks push for the development of novel collaborative North-South agendas in order to improve the fair distribution of benefits. The Green Health project (Guatemala) aims to implement a culturally pertinent and mutually accepted framework for sustainable use, access and benefit-sharing (ABS) of traditional medicinal plants. It involves developing a consensus among indigenous groups, government officials, industry, and academia. We describe steps undertaken to design and implement an intercultural transdisciplinary process that promotes trust building and advances herbal medicine research in a respectful and innovative way. This involves joint definition of goals and methods. The consortium co-researched Q’eqchi’ Maya traditional medicine, collected voucher specimens of medicinal plants with traditional healers, identified their taxa, and later developed a literature-based evaluation identifying species for potential product development. No samples for further research and development are collected. By applying the emic-etic concept, the project was able to understand the main drivers of each stakeholder and the associated obstacles for reaching an ABS agreement. This results in the emergence of potential new drivers for developing evidence-based herbal medicine from the perspective of academia, policy and cooperation and grass-roots indigenous movements

    Subchronic Exposure to TCDD, PeCDF, PCB126, and PCB153: Effect on Hepatic Gene Expression

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    We employed DNA microarray to identify unique hepatic gene expression patterns associated with subchronic exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and other halogenated aromatic hydrocarbons (HAHs). Female Harlan Sprague-Dawley rats were exposed for 13 weeks to toxicologically equivalent doses of four different HAHs based on the toxic equivalency factor of each chemical: TCDD (100 ng/kg/day), 2,3,4,7,8-pentachlorodibenzofuran (PeCDF; 200 ng/kg/day), 3,3′,4,4′,5-pentachlorobiphenyl (PCB126; 1,000 ng/kg/day), or 2,2′,4,4′,5,5′-hexachlorobiphenyl (PCB153; 1,000 μg/kg/day). Global gene expression profiles for each exposure, which account for 8,799 gene probe sets contained on Affymetrix RGU34A GeneChips, were compared by principal components analysis. The aryl hydrocarbon receptor (AhR) ligands TCDD, PeCDF, and PCB126 produced very similar global gene expression profiles that were unique from the nonAhR ligand PCB153, underscoring the extensive impact of AhR activation and/or the resulting hepatic injury on global gene expression in female rat liver. Many genes were co-expressed during the 13-week TCDD, PeCDF, or PCB126 exposures, including classical AhR-regulated genes and some genes not previously characterized as being AhR regulated, such as carcinoembryonic-cell adhesion molecule 4 (C-CAM4) and adenylate cyclase-associated protein 2 (CAP2). Real-time reverse-transcriptase polymerase chain reaction confirmed the increased expression of these genes in TCDD-, PeCDF-, and PCB126-exposed rats as well as the up- or down-regulation of several other novel dioxin-responsive genes. In summary, DNA microarray successfully identified dioxin-responsive genes expressed after exposure to AhR ligands (TCDD, PeCDF, PCB126) but not after exposure to the non-AhR ligand PCB153. Together, these findings may help to elucidate some of the fundamental features of dioxin toxicity and may further clarify the biologic role of the AhR signaling pathway

    Activated Magnetospheres of Magnetars

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    Like the solar corona, the external magnetic field of magnetars is twisted by surface motions of the star. The twist energy is dissipated over time. We discuss the theory of this activity and its observational status. (1) Theory predicts that the magnetosphere tends to untwist in a peculiar way: a bundle of electric currents (the "j-bundle") is formed with a sharp boundary, which shrinks toward the magnetic dipole axis. Recent observations of shrinking hot spots on magnetars are consistent with this behavior. (2) Continual discharge fills the j-bundle with electron-positron plasma, maintaining a nonthermal corona around the neutron star. The corona outside a few stellar radii strongly interacts with the stellar radiation and forms a "radiatively locked" outflow with a high e+- multiplicity. The locked plasma annihilates near the apexes of the closed magnetic field lines. (3) New radiative-transfer simulations suggest a simple mechanism that shapes the observed X-ray spectrum from 0.1 keV to 1 MeV: part of the thermal X-rays emitted by the neutron star are reflected from the outer corona and then upscattered by the inner relativistic outflow in the j-bundle, producing a beam of hard X-rays.Comment: 23 pages, 7 figures; review chapter in the proceedings of ICREA Workshop on the High-Energy Emission from Pulsars and Their Systems, Sant Cugat, Spain, April 201

    Mitochondrial genetic haplogroups and depressive symptoms: A large study among people in North America

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    Background: A possible relationship between mitochondrial haplogroups and psychiatric diseases (e.g. schizophrenia and bipolar disorder) has been postulated, but data regarding depression is still limited. We investigated whether any mitochondrial haplogroup carried a significant higher risk of depressive symptoms in a large prospective cohort of North American people included in the Osteoarthritis Initiative. Methods: Cross sectional data was derived from the Osteoarthritis Initiative. The haplogroup was assigned through a combination of sequencing and PCR-RFLP techniques. All the mitochondrial haplogroups were named following this nomenclature: H, U, K, J, T, V, SuperHV, I, W, X or Others. Depression was ascertained through the 20-item Center for Epidemiologic Studies- Depression (CES-D), with >16 indicating depressive symptoms. Results: Overall, 3,601 Caucasian participants (55.9% women), mean age of 61.7±9.3 years were included. No difference was observed in mitochondrial haplogroups frequency among those with depressive symptoms (n=285, =7.9% of the baseline population) compared to participants with no depressive symptoms (N=3,316) (chi-square test=0.53). Using a logistic regression analysis, adjusted for eight potential confounders, with those having the haplogroup H as the reference group (the most common haplogroup), no significant mitochondrial haplogroup was associated with prevalent depressive symptoms. The same results were evident in secondary analysis in which we matched depressed and non-depressed participants for age and sex. Limitations: cross-sectional design; only CES-D for evaluating mood; participants not totally representative of general population. Conclusions: We found no evidence of any relationship between specific mitochondrial haplogroups and depressive symptoms. Future longitudinal research is required to confirm/ refute these findings

    On the Relationship Between Ultrasonic and Micro-Structural Properties of Imperfect Interfaces in Layered Solids

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    The interaction of ultrasonic waves with interfaces formed by two non-conforming, rough surfaces in contact has been the subject of numerous investigations [1–10]. The motivations behind these studies have been various: from the assessment of the real area of contact between two rough surfaces [1], to the modeling of crack closure near the tip of a fatigue crack [4]; from the identification of the nature of interfacial imperfections in kissing and partial bonds [6], to the generation of ultrasonic waves [8]. In most of these studies, the characterization of the interfacial properties has been attempted by studying the reflection of longitudinal and shears waves at normal incidence. Only recently, the problem concerning the interaction of ultrasonic waves with realistic complex systems such as that formed by two neighboring imperfect interfaces has been addressed. Lavrentyev and Rokhlin [9, 10] used ultrasonic spectroscopy to evaluate the interfacial conditions from the spectra of longitudinal and shear waves reflected normally from the interfaces

    Little emperors in the UK: Acculturation and food over time

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    This is the post-print version of the final paper published in Journal of Business Research. The published article is available from the link below. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. Copyright @ 2011 Elsevier B.V.This paper investigates the acculturation process of a group of Chinese students living in the UK. It emerges from a longitudinal study looking at how participants' social ties affect their food consumption. Drafting from an interpretive study using focus groups discussions, it shows that participants' food consumption patterns change over time in relation to participants' social ties. Three acculturation phases have been individuated. They show that ethnic and non-ethnic ties influence participants' acculturation process. Students with strong ethnic ties consume Chinese food for maintaining their ethnic identity and resisting host food culture. Students with weak ethnic ties consume Chinese food to maintain their ethnic identity and global consumer culture food to resist host food culture. Participants with strong non-ethnic ties have a wider knowledge of host food culture, but they do not consume it more than students with weak non-ethnic ties
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