Irish Universities
Not a member yet
78452 research outputs found
Sort by
Effect of strain and many-body corrections on the band inversions and topology of bismuth
No full textThe electronic band structure of Bi is calculated using state of the art electronic structure methods, including density functional theory and G0W0 quasiparticle approximations. The delicate ordering of states at the L point of the Brillouin zone, which determines the topological character of the electronic bands, is investigated in detail. The effect on the bands of strain, changing the structural parameters of the rhombohedral crystal structure, is shown to be important in determining this ordering and the resulting topological character
Dietary Supplementation with a Magnesium-Rich Marine Mineral Blend Enhances the Diversity of Gastrointestinal Microbiota
No full textAccumulating evidence demonstrates that dietary supplementation with functional food ingredients play a role in systemic and brain health as well as in healthy ageing. Conversely, deficiencies in calcium and magnesium as a result of the increasing prevalence of a high fat/high sugar “Western diet” have been associated with health problems such as obesity, inflammatory bowel diseases, and cardiovascular diseases, as well as metabolic, immune, and psychiatric disorders. It is now recognized that modulating the diversity of gut microbiota, the population of intestinal bacteria, through dietary intervention can significantly impact upon gut health as well as systemic and brain health. In the current study, we show that supplementation with a seaweed and seawater-derived functional food ingredient rich in bioactive calcium and magnesium (0.1% supplementation) as well as 70 other trace elements, significantly enhanced the gut microbial diversity in adult male rats. Given the significant impact of gut microbiota on health, these results position this marine multi-mineral blend (MMB) as a promising digestive-health promoting functional food ingredient
Ranking connectivity risk for phosphorus loss along agricultural drainage ditches
No full textAgricultural drainage systems comprising both in-field pipe drains and surface ditches are typically
installed to remove excess water from agricultural land. These drainage networks can provide
connectivity between phosphorus (P) sources and surface waters thereby increasing the risk of P loss
to rivers and streams. The objective of this study was to derive a farm-scale drainage ranking that
categorises drainage ditches in terms of P loss risk based on connectivity and physic-chemical
characteristics. Ten pilot farms were selected to characterise drainage networks through ground
survey and, sediment and water sampling. Five drainage ditch categories were derived based on
landscape setting and connectivity. Each category recorded soluble and reactive P concentrations
above environmental water quality standards. To assess the risk of surface ditches as a connectivity
vector between agricultural P and surface waters ditches were ranked in order of P loss risk by
integrating landscape position and sediment P chemistry. Elevated sediment P with high equilibrium P
concentration (EPCo) were associated with ditches connected to farm yards, and in sediment sampled
at ditch outlets, suggesting P deposition over time indicative of a legacy P source. The greatest risk of
P loss was attributed to ditches connecting farm yards to streams, and ditches that connected the
drainage network to surface waters, or Outlets. These results rank connectivity risk for P loss along
agricultural drainage ditches for farm level risk assessment to target P loss mitigation measures to
the appropriate locations
Feature Extraction from Product Reviews using Feature Similarity and Polarity
No full textResearch on developing techniques to access user generated content, and specifically user reviews on different products, came in the focus of the information research community in recent past. In particular, this paper addresses the problem of extracting the features from user comments of a particular product, taking advantage of a corpus with a semistructured format: pros, cons and summary. In this paper we propose a technique to extract a set of features based on user generated pros and cons for a particular product. Then using this set we test a feature similarity function to obtain new features from reviews (both from the pros/cons and from the free text summary) of the same and other products. Our experimental results have shown interesting conclusions
A Spectral Co-Clustering Approach for Dynamic Data
No full textA common task in many domains with a temporal aspect involves identifying and tracking clusters over time. Often dynamic data will have a feature-based representation. In some cases, a direct mapping will exist for both objects and features over time. But in many scenarios, smaller subsets of objects or features alone will persist across successive time periods. To address this issue, we propose a dynamic spectral co-clustering algorithm for simultaneously clustering objects and features over time, as represented by a set of related bipartite graphs. We evaluate the algorithm on several synthetic datasets, a benchmark text corpus, and social bookmarking data.Science Foundation Irelan
Chemical and isotopic changes induced by pyrometamorphism in metasedimentary xenoliths at Tongariro volcano, New Zealand
No full textAndesites erupted from Tongariro volcano, North Island, New Zealand contain feldspathic and quartzose xenoliths derived from basement rocks. New major oxide, trace element and Sr-Nd-Pb isotopic data indicate that both the Waipapa and Kaweka (meta)sedimentary terranes are represented in erupted xenoliths, rather than only the Kaweka terrane as previously thought. Xenolith mineral assemblages differ from their likely source materials, notably through the lack of white mica, illite, chlorite and quartz, which is reflected in contrasting chemical and isotopic compositions. Major and trace element data indicate that most xenoliths underwent bulk mass decreases of about 50% when pyrometamorphosed at temperatures of ~800–980 °C, similar to typical Tongariro magma temperatures of ~800–1000 °C. Bulk Eu concentrations were retained (in restitic plagioclase); however, other rare earth elements are commonly lower in xenoliths than in protoliths. In xenoliths, the 143Nd/144Nd ratios of protoliths were also retained, which indicates that xenoliths were derived from the Kaweka and Waipapa terranes in subequal amounts. Reductions in 87Sr/86Sr ratios by up to 0.003 in xenoliths, relative to their likely protoliths, were accompanied by decreases in Rb/Sr ratios from 0.1–0.8 down to <0.1, reflecting the dissolution of hydrous, Rb-rich minerals (white mica ± illite) with their radiogenic isotopic ingrowths liberated into surrounding andesitic magmas. Varied amounts of U/Pb, Th/Pb and Th/U fractionation demonstrably occurred between xenoliths and protoliths, but these are challenging to correlate with Pb isotopic fractionation that also occurred. One xenolith contains a vein of clinopyroxene, calcic plagioclase, silicic glass and graphite that formed when quartz + calcite veins were pyrometamorphosed. The vein-bearing xenolith possesses unusual chemical and isotopic features, which include a negative Ce anomaly, LaN/YbN ~ 2 and high 143Nd/144Nd (0.51284), which are also reported for xenolithic material erupted at neighbouring Ruapehu volcano
On Sellars\u27 exam question trilemma: are Kant\u27s premises analytic, or synthetic a priori, or a posteriori?
No full textWilfrid Sellars argued that Kant’s account of the conceptual structures involved in experience can be given a linguistic turn so as to provide an analytic account of the resources a language must have in order to be the bearer of empirical knowledge. In this paper I examine the methodological aspects of Kant’s transcendental philosophy that Sellars took to be fundamental to influential themes in his own philosophy. My first aim here is to clarify and argue for the plausibility of what I claim is Sellars’ interpretation of Kant’s ‘analytic’ transcendental method in the first Critique, based ultimately on non-trivial analytic truths concerning the concept of an object of our possible experience. Kant’s ‘transcendental proofs’ thereby avoid a certain methodological trilemma confronting the candidate premises of any such proof, taken from Sellars’ 1970s undergraduate exam question on Kant. In part II of the essay I conclude by highlighting in general terms how Kant’s method, as interpreted in the analytic manner explained in part I, was adapted by Sellars to produce some of the more influential aspects of his own philosophy, expressed in terms of what he contends is their sustainable reformulation in light of the so-called linguistic turn in twentieth-century philosophy
The gut microbiome influences the bioavailability of olanzapine in rats
No full textBackground
The role of the gut microbiome in the biotransformation of drugs has recently come under scrutiny. It remains unclear whether the gut microbiome directly influences the extent of drug absorbed after oral administration and thus potentially alters clinical pharmacokinetics.
Methods
In this study, we evaluated whether changes in the gut microbiota of male Sprague Dawley rats, as a result of either antibiotic or probiotic administration, influenced the oral bioavailability of two commonly prescribed antipsychotics, olanzapine and risperidone.
Findings
The bioavailability of olanzapine, was significantly increased (1.8-fold) in rats that had undergone antibiotic-induced depletion of gut microbiota, whereas the bioavailability of risperidone was unchanged. There was no direct effect of microbiota depletion on the expression of major CYP450 enzymes involved in the metabolism of either drug. However, the expression of UGT1A3 in the duodenum was significantly downregulated. The reduction in faecal enzymatic activity, observed during and after antibiotic administration, did not alter the ex vivo metabolism of olanzapine or risperidone. The relative abundance of Alistipes significantly correlated with the AUC of olanzapine but not risperidone.
Interpretation
Alistipes may play a role in the observed alterations in olanzapine pharmacokinetics. The gut microbiome might be an important variable determining the systemic bioavailability of orally administered olanzapine. Additional research exploring the potential implication of the gut microbiota on the clinical pharmacokinetics of olanzapine in humans is warranted.
Funding
This research is supported by APC Microbiome Ireland, a research centre funded by Science Foundation Ireland (SFI), through the Irish Government\u27s National Development Plan (grant no. 12/RC/2273 P2) and by Nature Research-Yakult (The Global Grants for Gut Health; Ref No. 626891).Science Foundation Irelan
Magnetic impurities, integrable vortices and the Toda equation
No full textThe five integrable vortex equations, recently studied by Manton, are generalized to include magnetic impurities of the Tong–Wong type. Under certain conditions, these generalizations remain integrable. We further set up a gauge theory with a product gauge group, two complex scalar fields and a general charge matrix. The second species of vortices, when frozen, are interpreted as the magnetic impurity for all five vortex equations. We then give a geometric compatibility condition, which enables us to remove the constant term in all the equations. This is similar to the reduction from the Taubes equation to the Liouville equation. We further find a family of charge matrices that turn the five vortex equations into either the Toda equation or the Toda equation with the opposite sign. We find exact analytic solutions in all cases and the solution with the opposite sign appears to be new
Customary physical activity and odds of depression: a systematic review and meta-analysis of 111 prospective cohort studies
No full textObjective To explore whether physical activity is inversely associated with the onset of depression, we quantified the cumulative association of customary physical activity with incident depression and with an increase in subclinical depressive symptoms over time as reported from prospective observational studies. Design Systematic review and meta-analysis