157 research outputs found
Neutrino processes in partially degenerate neutron matter
We investigate neutrino processes for conditions reached in simulations of
core-collapse supernovae. Where neutrino-matter interactions play an important
role, matter is partially degenerate, and we extend earlier work that addressed
the degenerate regime. We derive expressions for the spin structure factor in
neutron matter, which is a key quantity required for evaluating rates of
neutrino processes. We show that, for essentially all conditions encountered in
the post-bounce phase of core-collapse supernovae, it is a very good
approximation to calculate the spin relaxation rates in the nondegenerate
limit. We calculate spin relaxation rates based on chiral effective field
theory interactions and find that they are typically a factor of two smaller
than those obtained using the standard one-pion-exchange interaction alone.Comment: 41 pages, 9 figures, NORDITA-2011-116; added comparison figures and
fit function for use in simulations, to appear in Astrophys.
Oxy Fuel for Clean Energy Generation
This process explores several concentrations of oxygen-enriched air streams (oxy fuel) in combination with natural gas to generate steam for a steam turbine power plant with 30 MW capacity. The proposed location for this plant is the gulf coast of the United States. The oxy fuel concentrations tested were 36 mol. %, 53 mol. %, and 95 mol. %. Nitrogen removed from air would be sold as well as the 30 MW of electricity. The three oxygen purities were not profitable for the most realistic prices of electricity, nitrogen, and natural gas. However, the scenarios were all profitable with prices of nitrogen above $0.015/lb. Additionally, the profitability could be improved with higher electricity prices or better thermal efficiency. A key takeaway is that the level of oxygen purity did not have a major effect on profitability for a given nitrogen price
A Double Payload Complex between Hypericin and All-trans Retinoic Acid in the β-Lactoglobulin Protein
Combined therapies are usually used to treat acne vulgaris since this approach can tackle various foci simultaneously. Using a combination of spectroscopic, computational, and microbiological techniques and methods, herein we report on the use of β-lactoglobulin as a double payload carrier of hypericin (an antimicrobial photodynamic agent) and all-trans retinoic acid (an anti-inflammatory drug) for S. aureus in vitro photodynamic inactivation. The addition of all-trans retinoic acid to hypericinβ-lactoglobulin complex renders a photochemically safe vehicle due to the photophysical quenching of hypericin, which recovers its photodynamic activity when in contact with bacteria. The ability of hypericin to photoinactivate S. aureus was not affected by retinoic acid. β-Lactoglobulin is a novel biocompatible and photochemically safe nanovehicle with strong potential for the treatment of acne
Exploring structure–activity relationships in photodynamic therapy anticancer agents based on Ir(III)-COUPY conjugates
Photodynamic therapy holds great promise as a non-invasive anticancer tool against drug-resistant cancers. However, highly effective, non-toxic, and reliable photosensitizers with operability under hypoxic conditions remain to be developed. Herein, we took the advantageous properties of COUPY fluorophores and cyclometalated Ir(III) complexes to develop novel PDT agents based on Ir(III)-COUPY conjugates with the aim of exploring structure–activity relationships. The structural modifications carried out within the coumarin scaffold had a strong impact on the photophysical properties and cellular uptake of the conjugates. All Ir(III)-COUPY conjugates exhibited high phototoxicity under green light irradiation, which was attributed to the photogeneration of ROS, while remaining non-toxic in the dark. Among them, two hit conjugates showed excellent phototherapeutic indexes in cisplatin-resistant A2780cis cancer cells, both in normoxia and in hypoxia, suggesting that photoactive therapy approaches based on the conjugation of far-red/NIR-emitting COUPY dyes and transition metal complexes could effectively tackle in vitro acquired resistance to cisplatin
Creating a community of praxis: integrating global citizenship and development education across campus at University College Cork
The Praxis Project, established at University College Cork (UCC), Ireland, in 2018, seeks to assess possible models of best practice with regard to the integration of global citizenship and development education (GCDE) into a cross-disciplinary, cross-campus, interwoven set of subject area pedagogies, policies and practices. This study – the first part of an eventual three-part framework – asserts that the themes, theories, values, skills, approaches and methodologies relevant to transformative pedagogical work are best underpinned by ongoing staff dialogue in order to build communities of support around such systemic pedagogical change. This article is based on a collaborative study with the first cohort of UCC staff (2020–1), which demonstrates many ways in which staff and students realised that smaller actions and carefully directed attention to specific issues opened doors to transformative thinking and action in surprising ways. From this viewpoint, the striking need emerged for taking a strategic approach to how GCDE is, and should be, integrated into learning across subject areas
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What has changed in the outbreaking populations of the severe crop pest whitefly species in cassava in two decades?
High populations of African cassava whitefly (Bemisia tabaci) have been associated with epidemics of two viral diseases in Eastern Africa. We investigated population dynamics and genetic patterns by comparing whiteflies collected on cassava in 1997, during the first whitefly upsurges in Uganda, with collections made in 2017 from the same locations. Nuclear markers and mtCOI barcoding sequences were used on 662 samples. The composition of the SSA1 population changed significantly over the 20-year period with the SSA1-SG2 percentage increasing from 0.9 to 48.6%. SSA1-SG1 and SSA1-SG2 clearly interbreed, confirming that they are a single biological species called SSA1. The whitefly species composition changed: in 1997, SSA1, SSA2 and B. afer were present; in 2017, no SSA2 was found. These data and those of other publications do not support the ‘invader’ hypothesis. Our evidence shows that no new species or new population were found in 20 years, instead, the distribution of already present genetic clusters composing SSA1 species have changed over time and that this may be in response to several factors including the introduction of new cassava varieties or climate changes. The practical implications are that cassava genotypes possessing both whitefly and disease resistances are needed urgently
Increasing voluntary medical male circumcision uptake among adult men in Tanzania.
OBJECTIVE: We evaluated a demand-creation intervention to increase voluntary medical male circumcision (VMMC) uptake among men aged 20-34 years in Tanzania, to maximise short-term impact on HIV incidence. METHODS: A cluster randomized controlled trial stratified by region was conducted in 20 outreach sites in Njombe and Tabora regions. The sites were randomized 1 : 1 to receive either a demand-creation intervention package in addition to standard VMMC outreach, or standard VMMC outreach alone. The intervention package included enhanced public address messages, peer promotion by recently circumcised men, facility setup to increase privacy, and engagement of female partners in demand creation. The primary outcome was the proportion of VMMC clients aged 20-34 years. FINDINGS: Overall, 6251 and 3968 VMMC clients were enrolled in intervention and control clusters, respectively. The proportion of clients aged 20-34 years was slightly greater in the intervention than control arm [17.7 vs. 13.0%; prevalence ratio = 1.36; 95% confidence intervals (CI):0.9-2.0]. In Njombe region, the proportion of clients aged 20-34 years was similar between arms but a significant two-fold difference was seen in Tabora region (P value for effect modification = 0.006). The mean number of men aged 20-34 years (mean difference per cluster = 97; 95% CI:40-154), and of all ages (mean difference per cluster = 227, 95% CI:33-420) were greater in the intervention than control arm. CONCLUSION: The intervention was associated with a significant increase in the proportion of clients aged 20-34 years in Tabora but not in Njombe. The intervention may be sensitive to regional factors in VMMC programme scale-up, including saturation
Sphalerons and the Electroweak Phase Transition in Models with Higher Scalar Representations
In this work we investigate the sphaleron solution in a
gauge theory, which also encompasses the Standard Model, with higher scalar
representation(s) (). We show that the field profiles
describing the sphaleron in higher scalar multiplet, have similar trends like
the doublet case with respect to the radial distance. We compute the sphaleron
energy and find that it scales linearly with the vacuum expectation value of
the scalar field and its slope depends on the representation. We also
investigate the effect of gauge field and find that it is small for the
physical value of the mixing angle, and resembles the case for the
doublet. For higher representations, we show that the criterion for strong
first order phase transition, , is relaxed with respect to
the doublet case, i.e. .Comment: 20 pages, 5 figures & 1 table, published versio
Voluntary Medical Male Circumcision: Matching Demand and Supply with Quality and Efficiency in a High-Volume Campaign in Iringa Region, Tanzania
Hally Mahler and colleagues evaluate a six-week voluntary medical male circumcision campaign in Iringa province of Tanzania, providing a model for matching supply with demand for services and showing that high-volume circumcisions can be performed without compromising client safety
Cost and Cost-Effectiveness of a Demand Creation Intervention to Increase Uptake of Voluntary Medical Male Circumcision in Tanzania: Spending More to Spend Less.
BACKGROUND: Although voluntary medical male circumcision (VMMC) reduces the risk of HIV acquisition, demand for services is lower among men in most at-risk age groups (ages 20-34 years). A randomized controlled trial was conducted to assess the effectiveness of locally-tailored demand creation activities (including mass media, community mobilization, and targeted service delivery) in increasing uptake of campaign-delivered VMMC among men aged 20-34 years. We conducted an economic evaluation to understand the intervention's cost and cost-effectiveness. SETTING: Tanzania (Njombe and Tabora regions). METHODS: Cost data were collected on surgery, demand creation activities, and monitoring and supervision related to VMMC implementation across clusters in both trial arms, as well as start-up activities for the intervention arms. The Decision Makers' Program Planning Tool was used to estimate the number of HIV infections averted and related cost savings, given the total VMMCs per cluster. Disability-adjusted life years were calculated and used to estimate incremental cost-effectiveness ratios. RESULTS: Client load was higher in the intervention arms than in the control arms: 4394 vs. 2901 in Tabora and 1797 vs. 1025 in Njombe, respectively. Despite additional costs of tailored demand creation, demand increased more than proportionally: mean costs per VMMC in the intervention arms were 130 in Njombe, and in the control arms 191, respectively. More infections were averted in the intervention arm than in the control arm in Tabora (123 vs. 67, respectively) and in Njombe (164 vs. 102, respectively). The intervention dominated the control because it was both less costly and more effective. Cost savings were observed in both regions stemming from the antiretroviral treatment costs averted as a result of the VMMCs performed. CONCLUSIONS: Spending more to address local preferences as a way to increase uptake of VMMC can be cost-saving
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