1,506 research outputs found

    Unusual but consistent latitudinal patterns in macroalgal habitats and their invertebrate communities across two countries

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    Aim: The physical characteristics of biogenic habitats and environmental conditions are important determinants of biodiversity, yet their relative importance can change across spatial scales. We aimed to understand how relationships between the physical characteristics of macroalgal habitats and their invertebrate communities varied across spatial scales and whether general ecological patterns occurred across two countries. Location: Eighteen sites across the temperate east coasts of Australia (over 1,300 km) and New Zealand (over 1,000 km), with the latitudinal gradient in the two countries overlapping by 6.73 decimal degrees. Time period: January to early April 2012. Major taxa studied: Three intertidal macroalgal habitats in each country and the invertebrate communities within them. Methods: We measured variation in patch- and individual-level characteristics of macroalgal habitats and their invertebrate communities. Patterns in macroalgal characteristics and communities were compared across latitude, and at smaller spatial scales, and correlated with 26 abiotic environmental variables using multiple multivariate analyses. Results: Separately, macroalgal habitat characteristics and communities showed unusual but consistent nonlinear latitudinal patterns, with greater similarity among sites at the edges of the sampled distribution (i.e., north and south) than at centrally located sites. Macroalgal characteristics did not correlate with a particular set of environmental variables; however, communities were structured by sea surface temperature at the country scale and by macroalgal habitat type and biomass within countries. Anthropogenic variables were also important and may have contributed to the unusual nonlinear patterns observed between macroalgal characteristics and communities across latitude. Main conclusions: Our results support other studies showing that large-scale patterns can emerge from systems where there is high local-scale variability. The results show that communities within macroalgal habitats respond to both the physical characteristics of the habitat and external environmental conditions (e.g., temperature), suggesting that local-scale environmental factors, including anthropogenic stressors, may modulate environmental gradients over larger scales

    Proximity of Iron Pnictide Superconductors to a Quantum Tricritical Point

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    We determine the nature of the magnetic quantum critical point in the doped LaFeAsO using a set of constrained density functional calculations that provide ab initio coefficients for a Landau order parameter analysis. The system turns out to be remarkably close to a quantum tricritical point, where the nature of the phase transition changes from first to second order. We compare with the effective field theory and discuss the experimental consequences.Comment: 4 pages, 4 figure

    Improvements in vision-related quality of life in blind patients implanted with the Argus II Epiretinal Prosthesis

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    Background: The purpose of this analysis is to report the change in quality of life (QoL) after treatment with the Argus II Epiretinal Prosthesis in patients with end-stage retinitis pigmentosa. Methods: The Vision and Quality of Life Index (VisQoL) was used to assess changes in QoL dimensions and overall utility score in a prospective 30-patient single-arm clinical study. VisQoL is a multi-attribute instrument consisting of six dimensions (injury, life, roles, assistance, activity and friendship) that may be affected by visual impairment. Within each dimension, patients were divided into two groups based on how much their QoL was affected by their blindness at baseline (moderate/severe or minimal). Outcomes were compared within each dimension sub-group between baseline and the combined follow-up periods using the Friedman test. In addition, data from the six dimensions were combined into a single utility score, with baseline data compared to the combined follow-up periods. Results: Overall, 80 per cent of the patients reported difficulty in one or more dimensions preimplant. Composite VisQoL utility scores at follow-up showed no statistically significant change from baseline; however, in three of the six VisQoL dimensions (injury, life and roles), patients with baseline deficits showed significant and lasting improvement after implantation with Argus II. In two of the three remaining dimensions (assistance and activity), data trended toward an improvement. In the final VisQoL dimension (friendship), none of the patients reported baseline deficits, suggesting that patients had largely adjusted to this attribute. Conclusion: Patients whose vision negatively affected them with respect to three VisQoL dimensions (that is, getting injured, coping with the demands of their life and fulfilling their life roles) reported significant improvement in QoL after implantation of the Argus II retinal prosthesis. Furthermore, the benefit did not deteriorate at any point during the 36-month follow-up, suggesting a long-term, durable improvement

    Influencia del conocimiento financiero en el bienestar financiero de usuarios de tarjeta de cr?dito y/o pr?stamos personales entre 18 y 79 a?os en Per? en el 2019

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    En raz?n de que existe incertidumbre y vac?os de informaci?n relacionados a la vulnerabilidad econ?mica y su relaci?n con el conocimiento financiero, esta investigaci?n tiene como objetivo determinar si el nivel de conocimiento financiero influy? significativamente en el bienestar financiero de los usuarios de tarjetas de cr?dito y pr?stamos personales de 18-79 a?os en el Per? en el a?o 2019. La metodolog?a empleada fue de tipo correlacional transversal, con dise?o no experimental. Se utiliz? como base de datos, la informaci?n de la Encuesta Nacional de Capacidades Financieras 2019, realizada por la SBS entre julio y agosto del 2019 a nivel nacional; y, como gu?a de determinaci?n de variables, metodolog?a y an?lisis, las provistas por la SBS y la OECD/INFE. La poblaci?n contiene 1205 observaciones; y, la muestra 219. Para el an?lisis se aplicaron: Prueba de Alfa de Cronbach; Prueba de correlaci?n de Pearson; Prueba de Rachas; y, Pruebas Logit Binomiales y Multinomiales. El estudio concluy? que el conocimiento financiero influy? significativamente en el bienestar financiero de los usuarios de tarjetas de cr?dito y pr?stamos personales de 18-79 a?os en el Per? en el a?o 2019

    Stabilization of angiotensin-(1-7) by key substitution with a cyclic non-natural amino acid

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    Angiotensin-(1-7) [Ang-(1-7)], a heptapeptide hormone of the renin-angiotensin-aldosterone system (RAAS), is a promising candidate as a treatment for cancer that reflects its antiproliferative and anti-angiogenic properties. However, the peptide’s therapeutic potential is limited by the short half-life and low bioavailability resulting from rapid enzymatic metabolism by peptidases including angiotensin-converting enzyme (ACE) and dipeptidyl peptidase 3 (DPP 3). We report the facile assembly of three novel Ang-(1-7) analogues by solid-phase peptide synthesis which incorporates the cyclic non-natural δ-amino acid ACCA. The analogues containing the ACCA substitution at the site of ACE cleavage exhibit complete resistance to human ACE, while substitution at the DDP3 cleavage site provided stability against DPP 3 hydrolysis. Furthermore, the analogues retain the anti-proliferative properties of Ang-(1-7) against the 4T1 and HT-1080 cancer cell lines. These results suggest that ACCA-substituted Ang-(1-7) analogues which show resistance against proteolytic degradation by peptidases known to hydrolyze the native heptapeptide may be novel therapeutics in the treatment of cancer

    What traits are carried on mobile genetic elements, and why?

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    Although similar to any other organism, prokaryotes can transfer genes vertically from mother cell to daughter cell, they can also exchange certain genes horizontally. Genes can move within and between genomes at fast rates because of mobile genetic elements (MGEs). Although mobile elements are fundamentally self-interested entities, and thus replicate for their own gain, they frequently carry genes beneficial for their hosts and/or the neighbours of their hosts. Many genes that are carried by mobile elements code for traits that are expressed outside of the cell. Such traits are involved in bacterial sociality, such as the production of public goods, which benefit a cell's neighbours, or the production of bacteriocins, which harm a cell's neighbours. In this study we review the patterns that are emerging in the types of genes carried by mobile elements, and discuss the evolutionary and ecological conditions under which mobile elements evolve to carry their peculiar mix of parasitic, beneficial and cooperative genes
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