2,199 research outputs found
Total-evidence framework reveals complex morphological evolution in nightbirds (Strisores)
Strisores is a clade of neoavian birds that include diurnal aerial specialists such as swifts and hummingbirds, as well as several predominantly nocturnal lineages such as nightjars and potoos. Despite the use of genome-scale molecular datasets, the phylogenetic interrelationships among major strisorean groups remain controversial. Given the availability of next-generation sequence data for Strisores and the cladeâs rich fossil record, we reassessed the phylogeny of Strisores by incorporating a large-scale sequence dataset with anatomical data from living and fossil strisoreans within a Bayesian total-evidence framework. Combined analyses of molecular and morphological data resulted in a phylogenetic topology for Strisores that is congruent with the findings of two recent molecular phylogenomic studies, supporting nightjars (Caprimulgidae) as the extant sister group of the remainder of Strisores. This total-evidence framework allowed us to identify morphological synapomorphies for strisorean clades previously recovered using molecular-only datasets. However, a combined analysis of molecular and morphological data highlighted strong signal conflict between sequence and anatomical data in Strisores. Furthermore, simultaneous analysis of molecular and morphological data recovered differing placements for some fossil taxa compared with analyses of morphological data under a molecular scaffold, highlighting the importance of analytical decisions when conducting morphological phylogenetic analyses of taxa with molecular phylogenetic data. We suggest that multiple strisorean lineages have experienced convergent evolution across the skeleton, obfuscating the phylogenetic position of certain fossils, and that many distinctive specializations of strisorean subclades were acquired early in their evolutionary history. Despite this apparent complexity in the evolutionary history of Strisores, our results provide fossil support for aerial foraging as the ancestral ecological strategy of Strisores, as implied by recent phylogenetic topologies derived from molecular data.Parts of this project were supported by Systematics Research Fund awards to A.C. and D.J.F. by the Linnean Society of London and the Systematics Association. D.J.F. also acknowledges support from the Isaac Newton Trust early career support scheme. Parts of this project were also funded by the European Unionâs Horizon 2020 research and innovation program 2014â2018 under grant agreement 677774 (European Research Council [ERC] Starting Grant: TEMPO) to R.B.J.B. N.D.W. and M.J.B. received Smithsonian Institution support through the Predoctoral Fellowship Program (N.D.W.), the Frontiers in Phylogenetics Program, the Scholarly Studies Program, and the Consortium for Understanding and Sustaining a Biodiverse Planet
2,1,3-Benzothiadiazole-5,6-Dicarboxylic Imide - A Versatile Building Block for Additive-and Annealing-Free Processing of Organic Solar Cells with Effi ciencies Exceeding 8%
A new photoactive polymer comprising benzo[1,2âb:3,4âbâČ:5,6âdâČ]trithiophene and 2,1,3âbenzothiadiazoleâ5,6âdicarboxylic imide is reported. The synthetic design allows for alkyl chains to be introduced on both electronârich and electronâdeficient components, which in turn allows for rapid optimization of the alkyl chain substitution pattern. Consequently, the optimized polymer shows a maximum efficiency of 8.3% in organic photovoltaic devices processed in a commercially viable fashion without solvent additives, annealing, or device engineering
Automatic estimation of harmonic tension by distributed representation of chords
The buildup and release of a sense of tension is one of the most essential
aspects of the process of listening to music. A veridical computational model
of perceived musical tension would be an important ingredient for many music
informatics applications. The present paper presents a new approach to
modelling harmonic tension based on a distributed representation of chords. The
starting hypothesis is that harmonic tension as perceived by human listeners is
related, among other things, to the expectedness of harmonic units (chords) in
their local harmonic context. We train a word2vec-type neural network to learn
a vector space that captures contextual similarity and expectedness, and define
a quantitative measure of harmonic tension on top of this. To assess the
veridicality of the model, we compare its outputs on a number of well-defined
chord classes and cadential contexts to results from pertinent empirical
studies in music psychology. Statistical analysis shows that the model's
predictions conform very well with empirical evidence obtained from human
listeners.Comment: 12 pages, 4 figures. To appear in Proceedings of the 13th
International Symposium on Computer Music Multidisciplinary Research (CMMR),
Porto, Portuga
Effects of comorbidities on quality of life in Filipino people with tuberculosis.
BACKGROUND: We investigated health-related quality of life (HrQoL) in Filipino people undergoing TB treatment, and whether HrQoL was negatively impacted by comorbidity with undernutrition, diabetes (DM) and anaemia.METHODS: Adult participants were enrolled in public facilities in Metro Manila (three sites) and Negros Occidental (two sites). Multivariate linear regression was used to model the four correlated domain scores from a WHOQOL-BREF questionnaire (physical, psychological, social, environmental). A forward-stepwise approach was used to select a final multivariable model with inclusion based on global tests of significance at P < 0.1.RESULTS: In 446 people on drug-susceptible TB treatment, DM and moderate/severe anaemia were not associated with HrQoL. After adjustment for age, sex, education, food insecurity, treatment adherence, inflammation, Category I or II TB treatment, treatment phase, current side effects and inhibited ability to work, moderate/severe undernutrition (body mass index < 17 kg/mÂČ) was associated with lower HrQoL (P = 0.003) with reduced psychological (coefficient: -1.02, 95% CI -1.54 to -0.51), physical (-0.62, 95% CI -1.14 to -0.09) and environmental domain scores (-0.45, 95% CI -0.88 to -0.01). In 225 patients with known HIV status in Metro Manila, HIV was associated with modestly reduced HrQoL (P = 0.014).CONCLUSION: Nutritional status and food insecurity represent modifiable risk factors for poor HrQoL that may be alleviated through interventions
Cercosporoid leaf pathogens from whorled milkweed and spineless safflower in California
Two cercosporoid species are respectively described from Mexican whorled milkweed (Asclepias fascicularis), and spineless safflower (Carthamus tinctorius) from California. Passalora californica represents a new pathogen on Asclepias fascicularis, while Ramularia cynarae is confirmed on Carthamus tinctorius and Cynara cardunculus (Asteraceae), and an epitype designated. Pathogenicity is also established for both pathogens based on Kochâs postulate
Altered Ratio of D1 and D2 Dopamine Receptors in Mouse Striatum Is Associated with Behavioral Sensitization to Cocaine
BACKGROUND: Drugs of abuse elevate brain dopamine levels, and, in vivo, chronic drug use is accompanied by a selective decrease in dopamine D2 receptor (D2R) availability in the brain. Such a decrease consequently alters the ratio of D1R:D2R signaling towards the D1R. Despite a plethora of behavioral studies dedicated to the understanding of the role of dopamine in addiction, a molecular mechanism responsible for the downregulation of the D2R, in vivo, in response to chronic drug use has yet to be identified. METHODS AND FINDINGS: ETHICS STATEMENT: All animal work was approved by the Gallo Center IACUC committee and was performed in our AAALAC approved facility. In this study, we used wild type (WT) and G protein coupled receptor associated sorting protein-1 (GASP-1) knock out (KO) mice to assess molecular changes that accompany cocaine sensitization. Here, we show that downregulation of D2Rs or upregulation of D1Rs is associated with a sensitized locomotor response to an acute injection of cocaine. Furthermore, we demonstrate that disruption of GASP-1, that targets D2Rs for degradation after endocytosis, prevents cocaine-induced downregulation of D2Rs. As a consequence, mice with a GASP-1 disruption show a reduction in the sensitized locomotor response to cocaine. CONCLUSIONS: Together, our data suggests that changes in the ratio of the D1:D2R could contribute to cocaine-induced behavioral plasticity and demonstrates a role of GASP-1 in regulating both the levels of the D2R and cocaine sensitization
Increased plasma membrane cholesterol in cystic fibrosis cells correlates with CFTR genotype and depends on de novo cholesterol synthesis
<p>Abstract</p> <p>Background</p> <p>Previous observations demonstrate that <it>Cftr</it>-null cells and tissues exhibit alterations in cholesterol processing including perinuclear cholesterol accumulation, increased <it>de novo </it>synthesis, and an increase in plasma membrane cholesterol accessibility compared to wild type controls. The hypothesis of this study is that membrane cholesterol accessibility correlates with CFTR genotype and is in part influenced by <it>de novo </it>cholesterol synthesis.</p> <p>Methods</p> <p>Electrochemical detection of cholesterol at the plasma membrane is achieved with capillary microelectrodes with a modified platinum coil that accepts covalent attachment of cholesterol oxidase. Modified electrodes absent cholesterol oxidase serves as a baseline control. Cholesterol synthesis is determined by deuterium incorporation into lipids over time. Incorporation into cholesterol specifically is determined by mass spectrometry analysis. All mice used in the study are on a C57Bl/6 background and are between 6 and 8 weeks of age.</p> <p>Results</p> <p>Membrane cholesterol measurements are elevated in both R117H and ÎF508 mouse nasal epithelium compared to age-matched sibling wt controls demonstrating a genotype correlation to membrane cholesterol detection. Expression of wt CFTR in CF epithelial cells reverts membrane cholesterol to WT levels further demonstrating the impact of CFTR on these processes. In wt epithelial cell, the addition of the CFTR inhibitors, Gly H101 or CFTR<sub>inh</sub>-172, for 24 h surprisingly results in an initial drop in membrane cholesterol measurement followed by a rebound at 72 h suggesting a feedback mechanism may be driving the increase in membrane cholesterol. <it>De novo </it>cholesterol synthesis contributes to membrane cholesterol accessibility.</p> <p>Conclusions</p> <p>The data in this study suggest that CFTR influences cholesterol trafficking to the plasma membrane, which when depleted, leads to an increase in <it>de novo </it>cholesterol synthesis to restore membrane content.</p
Measurements on the reality of the wavefunction
Quantum mechanics is an outstandingly successful description of nature,
underpinning fields from biology through chemistry to physics. At its heart is
the quantum wavefunction, the central tool for describing quantum systems. Yet
it is still unclear what the wavefunction actually is: does it merely represent
our limited knowledge of a system, or is it an element of reality? Recent no-go
theorems argued that if there was any underlying reality to start with, the
wavefunction must be real. However, that conclusion relied on debatable
assumptions, without which a partial knowledge interpretation can be maintained
to some extent. A different approach is to impose bounds on the degree to which
knowledge interpretations can explain quantum phenomena, such as why we cannot
perfectly distinguish non-orthogonal quantum states. Here we experimentally
test this approach with single photons. We find that no knowledge
interpretation can fully explain the indistinguishability of non-orthogonal
quantum states in three and four dimensions. Assuming that some underlying
reality exists, our results strengthen the view that the entire wavefunction
should be real. The only alternative is to adopt more unorthodox concepts such
as backwards-in-time causation, or to completely abandon any notion of
objective reality.Comment: 7 pages, 4 figure
Network 'small-world-ness': a quantitative method for determining canonical network equivalence
Background: Many technological, biological, social, and information networks fall into the broad class of 'small-world' networks: they have tightly interconnected clusters of nodes, and a shortest mean path length that is similar to a matched random graph (same number of nodes and edges). This semi-quantitative definition leads to a categorical distinction ('small/not-small') rather than a quantitative, continuous grading of networks, and can lead to uncertainty about a network's small-world status. Moreover, systems described by small-world networks are often studied using an equivalent canonical network model-the Watts-Strogatz (WS) model. However, the process of establishing an equivalent WS model is imprecise and there is a pressing need to discover ways in which this equivalence may be quantified.
Methodology/Principal Findings: We defined a precise measure of 'small-world-ness' S based on the trade off between high local clustering and short path length. A network is now deemed a 'small-world' if S. 1-an assertion which may be tested statistically. We then examined the behavior of S on a large data-set of real-world systems. We found that all these systems were linked by a linear relationship between their S values and the network size n. Moreover, we show a method for assigning a unique Watts-Strogatz (WS) model to any real-world network, and show analytically that the WS models associated with our sample of networks also show linearity between S and n. Linearity between S and n is not, however, inevitable, and neither is S maximal for an arbitrary network of given size. Linearity may, however, be explained by a common limiting growth process.
Conclusions/Significance: We have shown how the notion of a small-world network may be quantified. Several key properties of the metric are described and the use of WS canonical models is placed on a more secure footing
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