313 research outputs found
Rhythmic maximal evenness: rhythm in voice-leading space
Maximal evenness was first introduced in the music theory domain by John Clough and Jack Douthett. Later, the concept was explored by others such as Dmitri Tymoczko and Richard Cohn. Although maximal evenness was first explored with respect to pitch-classes, the concept can be understood in the rhythmic domain. An explanation of voice-leading space can be found here to create a conceptual foundation before departing to the implications of maximal evenness on rhythm. This thesis will then explore the concept further by exploring music from Steve Reich and György Ligeti to demonstrate the applicability and deeper understanding of the concept
Economic inequalities in the effectiveness of a primary care intervention for depression and suicidal ideation.
BACKGROUND: Economic disadvantage is associated with depression and suicide. We sought to determine whether economic disadvantage reduces the effectiveness of depression treatments received in primary care. METHODS: We conducted differential-effects analyses of the Prevention of Suicide in Primary Care Elderly: Collaborative Trial, a primary-care-based randomized, controlled trial for late-life depression and suicidal ideation conducted between 1999 and 2001, which included 514 patients with major depression or clinically significant minor depression. RESULTS: The intervention effect, defined as change in depressive symptoms from baseline, was stronger among persons reporting financial strain at baseline (differential effect size = -4.5 Hamilton Depression Rating Scale points across the study period [95% confidence interval = -8.6 to -0.3]). We found similar evidence for effect modification by neighborhood poverty, although the intervention effect weakened after the initial 4 months of the trial for participants residing in poor neighborhoods. There was no evidence of substantial differences in the effectiveness of the intervention on suicidal ideation and depression remission by economic disadvantage. CONCLUSIONS: Economic conditions moderated the effectiveness of primary-care-based treatment for late-life depression. Financially strained individuals benefited more from the intervention; we speculate this was because of the enhanced treatment management protocol, which led to a greater improvement in the care received by these persons. People living in poor neighborhoods experienced only temporary benefit from the intervention. Thus, multiple aspects of economic disadvantage affect depression treatment outcomes; additional work is needed to understand the underlying mechanisms
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Translational potential of long-term decreases in mitochondrial lipids in a mouse model of Gulf War Illness
Gulf War Illness (GWI) affects 25% of veterans from the 1990â1991 Gulf War (GW) and is accompanied by damage to the brain regions involved in memory processing. After twenty-five years, the chronic pathobiology of GWI is still unexplained. To address this problem, we examined the long-term consequences of GW exposures in an established GWI mouse model to identify biological processes that are relevant to the chronic symptoms of GWI. Three-month old male C57BL6 mice were exposed for 10 days to GW agents (pyridostigmine bromide and permethrin). Barnes Maze testing conducted at 15- and 16-months post-exposure revealed learning and memory impairment. Immunohistochemical analyses showed astroglia and microglia activation in the hippocampi of exposed mice. Proteomic studies identified perturbation of mitochondria function and metabolomics data showed decreases in the Krebs cycle compounds, lactate, ÎČ-hydroxybutyrate and glycerol-3 phosphate in the brains of exposed mice. Lipidomics data showed decreases in fatty acids, acylcarnitines and phospholipids, including cardiolipins in the brains of exposed mice. Pilot biomarker studies showed that plasma from exposed mice and veterans with GWI had increases in odd-chain, and decreases in long-chain, acylcarnitines compared to their respective controls. Very long-chain acylcarnitines were decreased in veterans with GWI compared to controls. These studies suggest that mitochondrial lipid disturbances might be associated with GWI and that further investigation is required to determine its role in the pathophysiology of this illness. Targeting mitochondrial function may provide effective therapies for GWI, and that lipid abnormalities could serve as biomarkers of GWI
Chemical Evolution of Fluorine in the Milky Way
Fluorine has many different potential sites and channels of production, making narrowing down a dominant site of fluorine production particularly challenging. In this work, we investigate which sources are the dominant contributors to the galactic fluorine by comparing chemical evolution models to observations of fluorine abundances in Milky Way stars covering a metallicity range of â2â<â[Fe/H]â<â0.4 and upper limits in the range of â3.4â<â[Fe/H]â<ââ2.3. In our models, we use a variety of stellar yield sets in order to explore the impact of varying both asymptotic giant branch (AGB) and massive star yields on the chemical evolution of fluorine. In particular, we investigate different prescriptions for initial rotational velocity in massive stars as well as a metallicity-dependent mix of rotational velocities. We find that the observed [F/O] and [F/Fe] abundance ratios at low metallicity and the increasing trend of [F/Ba] at [Fe/H]ââłââ1 can only be reproduced by chemical evolution models assuming, at all metallicities, a contribution from rapidly rotating massive stars with initial rotational velocities as high as 300âkm sâ1. A mix of rotational velocities may provide a more physical solution than the sole use of massive stars with vrotâ = â300âkmâsâ1, which are predicted to overestimate the fluorine and average s-process elemental abundances at [Fe/H]ââłââ1. The contribution from AGB stars is predicted to start at [Fe/H]ââââ1 and becomes increasingly important at high metallicity, being strictly coupled to the evolution of the nitrogen abundance. Finally, by using modern yield sets, we investigate the fluorine abundances of WolfâRayet winds, ruling them out as dominant contributors to the galactic fluorine
Aggregation and Representation in the European Parliament Party Groups
While members of the European Parliament are elected in national constituencies, their votes are determined by the aggregation of MEPs in multinational party groups. The uncoordinated aggregation of national party programmes in multinational EP party groups challenges theories of representation based on national parties and parliaments. This article provides a theoretical means of understanding representation by linking the aggregation of dozens of national party programmes in different EP party groups to the aggregation of groups to produce the parliamentary majority needed to enact policies. Drawing on an original data source of national party programmes, the EU Profiler, the article shows that the EP majorities created by aggregating MEP votes in party groups are best explained by cartel theories. These give priority to strengthening the EPâs collective capacity to enact policies rather than voting in accord with the programmes they were nationally elected to represent
Aluminium-26 from Massive Binary Stars. I. Nonrotating Models
Aluminium-26 is a short-lived radionuclide with a half-life of 0.72 Myr, which is observed today in the Galaxy via Îł-ray spectroscopy and i inferred to have been present in the early solar system via analysis o meteorites. Massive stars are considered the main contributors o 26Al. Although most massive stars are found in binar systems, the effect, however, of binary interactions on th 26Al yields has not been investigated since Braun & Langer. Here we aim to fill this gap. We have used the MESA stella evolution code to compute massive (10 M â †M †80 â) nonrotating single and binary stars of solar metallicit (Z = 0.014). We computed the wind yields for the single stars and fo the binary systems where mass transfer plays a major role. Depending o the initial mass of the primary star and orbital period, th 26Al yield can either increase or decrease in a binar system. For binary systems with primary masses up to âŒ35â40 â, the yield can increase significantly, especially at th lower mass end, while above âŒ45 M â the yield becomes simila to the single-star yield or even decreases. Our preliminary results sho that compared to supernova explosions, the contribution of mass loss i binary systems to the total 26Al abundance produced by stellar population is minor. On the other hand, if massive star mas loss is the origin of 26Al in the early solar system, ou results will have significant implications for the identification of th potential stellar, or stellar population, source. This paper i dedicated to the celebration of the 100th birthday of Margaret Burbidge in recognition of the outstanding contributions she has made to nuclea astrophysics (Burbidge et al. 1957
Progress on nuclear reaction rates affecting the stellar production of 26Al
The radioisotope 26Al is a key observable for nucleosynthesis in the Galaxy and the environment of the early Solar System. To properly interpret the large variety of astronomical and meteoritic data, it is crucial to understand both the nuclear reactions involved in the production of 26Al in the relevant stellar sites and the physics of such sites. These range from the winds of low- and intermediate-mass asymptotic giant branch stars; to massive and very massive stars, both their WolfâRayet winds and their final core-collapse supernovae (CCSN); and the ejecta from novae, the explosions that occur on the surface of a white dwarf accreting material from a stellar companion. Several reactions affect the production of 26Al in these astrophysical objects, including (but not limited to) 25Mg(p, Âż)26Al, 26Al(p, Âż)27Si, and 26Al(n, p/a). Extensive experimental effort has been spent during recent years to improve our understanding of such key reactions. Here we present a summary of the astrophysical motivation for the study of 26Al, a review of its production in the different stellar sites, and a timely evaluation of the currently available nuclear data. We also provide recommendations for the nuclear input into stellar models and suggest relevant, future experimental work.Postprint (published version
Examination of the rumen bacteria and methanogenic archaea of wild impalas (Aepyceros melampus melampus) from Pongola, South Africa
Although the rumen microbiome of domesticated
ruminants has been evaluated, few studies have explored the
rumen microbiome of wild ruminants, and no studies have
identified the rumen microbiome in the impala (Aepyceros
melampus melampus). In the present study, next-generation
sequencing and real-time polymerase chain reaction were
used to investigate the diversity and density of the bacteria
and methanogenic archaea residing in the rumen of five adult
male impalas, culled during the winter dry season in Pongola,
South Africa. A total of 15,323 bacterial 16S rRNA gene
sequences (from five impala), representing 3,892 different
phylotypes, were assigned to 1,902 operational taxonomic
units (OTUs). A total of 20,124 methanogen 16S rRNA gene
sequence reads (from four impala), of which 5,028 were
unique, were assigned to 344 OTUs. From the total sequence
reads, Bacteroidetes, Proteobacteria, and Firmicutes were the
most abundant bacterial phyla. While the majority of the
bacterial genera found were unclassified, Prevotella and
Cupriavidus were the most abundant classified genera. For
methanogens, the genera Methanobrevibacter and
Methanosphaera represented 94.3 % and 4.0 % of the classified
sequences, respectively. Most notable was the identification
of Methanobrevibacter thaueri-like 16S rRNA gene sequence
reads in all four impala samples, representing greater than 30 % of each individualâs total sequences. Both data sets
are accessible through NCBIâs Sequence Read Archive (SRA),
under study accession number SRP [048619]. The densities of
bacteria (1.26Ă1010â3.82Ă1010 cells/ml whole rumen contents)
and methanogens (4.48Ă108â7.2Ă109 cells/ml of whole
rumen contents) from five individual impala were similar to
those typically observed in domesticated ruminants.http://link.springer.com/journal/2482016-04-30hb201
The RADIOSTAR Project
© 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).Radioactive nuclei are the key to understanding the circumstances of the birth of our Sun because meteoritic analysis has proven that many of them were present at that time. Their origin, however, has been so far elusive. The ERC-CoG-2016 RADIOSTAR project is dedicated to investigating the production of radioactive nuclei by nuclear reactions inside stars, their evolution in the Milky Way Galaxy, and their presence in molecular clouds. So far, we have discovered that: (i) radioactive nuclei produced by slow (107Pd and 182Hf) and rapid (129I and 247Cm) neutron captures originated from stellar sources âasymptotic giant branch (AGB) stars and compact binary mergers, respectivelyâwithin the galactic environment that predated the formation of the molecular cloud where the Sun was born; (ii) the time that elapsed from the birth of the cloud to the birth of the Sun was of the order of 107 years, and (iii) the abundances of the very short-lived nuclei 26Al, 36Cl, and 41Ca can be explained by massive star winds in single or binary systems, if these winds directly polluted the early Solar System. Our current and future work, as required to finalise the picture of the origin of radioactive nuclei in the Solar System, involves studying the possible origin of radioactive nuclei in the early Solar System from core-collapse supernovae, investigating the production of 107Pd in massive star winds, modelling the transport and mixing of radioactive nuclei in the galactic and molecular cloud medium, and calculating the galactic chemical evolution of 53Mn and 60Fe and of the p-process isotopes 92Nb and 146Sm.Peer reviewedFinal Published versio
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