329 research outputs found
Tephritids of knapweeds, starthistles and safflower: results of a host choice experiment and the taxonomy of Terellia luteola (Wiedemann) (Diptera: Tephritidae)
A host choice experiment was carried out to determine the host range of some potential biological control agents of yellow starthistle (Centaurea solstitialis), a Mediterranean plant which has become a serious rangeland weed in western USA. This paper describes the results of that experiment and discusses its taxonomic implications. The experiment confirmed the extreme host specificity of some species. However, two reputedly polyphagous species, Acanthiophilus helianthi (Rossi) and Urophora quadrifasciata (Meigen), attacked a narrower range of hosts than expected. The results of this and similar host choice experiments are discussed and it is concluded that this sort of anomaly can be caused by the existence of host races, unrecognized sibling species, or by varieties of plants naturally resistant to attack. These complex patterns of host relationship highlight the need to interpret host catalogue data cautiously, as they oversimplify complex biological systems. The identity of one species reared in the experiment, Terellia luteola (Wiedemann), is discussed; a key is presented for its separation from other Terellia species, and it is removed from synonymy with T. colon (Meigen
Combining task-evoked and spontaneous activity to improve pre-operative brain mapping with fMRI
Noninvasive localization of brain function is used to understand and treat neurological disease, exemplified by pre-operative fMRI mapping prior to neurosurgical intervention. The principal approach for generating these maps relies on brain responses evoked by a task and, despite known limitations, has dominated clinical practice for over 20years. Recently, pre-operative fMRI mapping based on correlations in spontaneous brain activity has been demonstrated, however this approach has its own limitations and has not seen widespread clinical use. Here we show that spontaneous and task-based mapping can be performed together using the same pre-operative fMRI data, provide complimentary information relevant for functional localization, and can be combined to improve identification of eloquent motor cortex. Accuracy, sensitivity, and specificity of our approach are quantified through comparison with electrical cortical stimulation mapping in eight patients with intractable epilepsy. Broad applicability and reproducibility of our approach are demonstrated through prospective replication in an independent dataset of six patients from a different center. In both cohorts and every individual patient, we see a significant improvement in signal to noise and mapping accuracy independent of threshold, quantified using receiver operating characteristic curves. Collectively, our results suggest that modifying the processing of fMRI data to incorporate both task-based and spontaneous activity significantly improves functional localization in pre-operative patients. Because this method requires no additional scan time or modification to conventional pre-operative data acquisition protocols it could have widespread utility
Corticocortical evoked potentials reveal projectors and integrators in human brain networks.
The cerebral cortex is composed of subregions whose
functional specialization is largely determined by their
incoming and outgoing connections with each other. In the
present study, we asked which cortical regions can exert the
greatest influence over other regions and the cortical
network as a whole. Previous research on this question has
relied on coarse anatomy (mapping large fiber pathways) or
functional connectivity (mapping inter-regional statistical
dependencies in ongoing activity). Here we combined direct
electrical stimulation with recordings from the cortical
surface to provide a novel insight into directed, inter-
regional influence within the cerebral cortex of awake
humans. These networks of directed interaction were
reproducible across strength thresholds and across subjects.
Directed network properties included (1) a decrease in the
reciprocity of connections with distance; (2) major projector
nodes (sources of influence) were found in peri-Rolandic
cortex and posterior, basal and polar regions of the temporal
lobe; and (3) major receiver nodes (receivers of influence)
were found in anterolateral frontal, superior parietal, and
superior temporal regions. Connectivity maps derived from
electrical stimulation and from resting electrocorticography
(ECoG) correlations showed similar spatial distributions for
the same source node. However, higher-level network topology
analysis revealed differences between electrical stimulation
and ECoG that were partially related to the reciprocity of
connections. Together, these findings inform our
understanding of large-scale corticocortical influence as
well as the interpretation of functional connectivity
networks
Importance of Anatomical Efficacy for Disease Control in Neovascular AMD: An Expert Opinion
BACKGROUND: Neovascular age-related macular degeneration (nAMD) presents a significant treatment burden for patients, carers and medical retina services. However, significant debate remains regarding how best to manage nAMD when assessing disease activity by optical coherence tomography (OCT), and particularly the significance of different types of fluid and how the understanding of anatomical efficacy can influence treatment strategies. This article provides opinion on the practical implications of anatomical efficacy and significance of fluid in the management of nAMD and proposes recommendations for healthcare professionals (HCPs) to improve understanding and promote best practice to achieve disease control. METHODS: An evidence-based review was performed and an expert panel debate from the Retina Outcomes Group (ROG), a forum of retinal specialists, provided insights and recommendations on the definition, role and practical implications of anatomical efficacy and the significance of fluid at the macula in the management of nAMD. RESULTS: The ROG has developed recommendations for achieving disease control through a zero-tolerance approach to the presence of fluid in nAMD as patients who avoid fluctuations in fluid at the macula have better visual outcomes. Recommendations cover five key areas: service protocol, training, regimen, multidisciplinary teams and engagement. This approach facilitates more standardised protocol-based treatment strategies. CONCLUSIONS: Targeting a fluid-free macula and aiming for disease control are essential to improve outcomes. As new therapies and technologies become available, drying the macula and maintaining disease control will become even more achievable. The outlined recommendations aim to promote best practice among HCPs and medical retina services to improve patient outcomes
Cellular Hypoxia Promotes Heterotopic Ossification by Amplifying BMP Signaling
Hypoxia and inflammation are implicated in the episodic induction of heterotopic endochondral ossification (HEO); however, the molecular mechanisms are unknown. HIFĆ¢ 1ĆĀ± integrates the cellular response to both hypoxia and inflammation and is a prime candidate for regulating HEO. We investigated the role of hypoxia and HIFĆ¢ 1ĆĀ± in fibrodysplasia ossificans progressiva (FOP), the most catastrophic form of HEO in humans. We found that HIFĆ¢ 1ĆĀ± increases the intensity and duration of canonical bone morphogenetic protein (BMP) signaling through Rabaptin 5 (RABEP1)Ć¢ mediated retention of Activin A receptor, type I (ACVR1), a BMP receptor, in the endosomal compartment of hypoxic connective tissue progenitor cells from patients with FOP. We further show that early inflammatory FOP lesions in humans and in a mouse model are markedly hypoxic, and inhibition of HIFĆ¢ 1ĆĀ± by genetic or pharmacologic means restores canonical BMP signaling to normoxic levels in human FOP cells and profoundly reduces HEO in a constitutively active Acvr1Q207D/+ mouse model of FOP. Thus, an inflammation and cellular oxygenĆ¢ sensing mechanism that modulates intracellular retention of a mutant BMP receptor determines, in part, its pathologic activity in FOP. Our study provides critical insight into a previously unrecognized role of HIFĆ¢ 1ĆĀ± in the hypoxic amplification of BMP signaling and in the episodic induction of HEO in FOP and further identifies HIFĆ¢ 1ĆĀ± as a therapeutic target for FOP and perhaps nongenetic forms of HEO. ĆĀ© 2016 American Society for Bone and Mineral Research.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/134262/1/jbmr2848_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/134262/2/jbmr2848.pd
Biological activity differences between TGF-Ī²1 and TGF-Ī²3 correlate with differences in the rigidity and arrangement of their component monomers
[Image: see text] TGF-Ī²1, -Ī²2, and -Ī²3 are small, secreted signaling proteins. They share 71ā80% sequence identity and signal through the same receptors, yet the isoform-specific null mice have distinctive phenotypes and are inviable. The replacement of the coding sequence of TGF-Ī²1 with TGF-Ī²3 and TGF-Ī²3 with TGF-Ī²1 led to only partial rescue of the mutant phenotypes, suggesting that intrinsic differences between them contribute to the requirement of each in vivo. Here, we investigated whether the previously reported differences in the flexibility of the interfacial helix and arrangement of monomers was responsible for the differences in activity by generating two chimeric proteins in which residues 54ā75 in the homodimer interface were swapped. Structural analysis of these using NMR and functional analysis using a dermal fibroblast migration assay showed that swapping the interfacial region swapped both the conformational preferences and activity. Conformational and activity differences were also observed between TGF-Ī²3 and a variant with four helix-stabilizing residues from TGF-Ī²1, suggesting that the observed changes were due to increased helical stability and the altered conformation, as proposed. Surface plasmon resonance analysis showed that TGF-Ī²1, TGF-Ī²3, and variants bound the type II signaling receptor, TĪ²RII, nearly identically, but had small differences in the dissociation rate constant for recruitment of the type I signaling receptor, TĪ²RI. However, the latter did not correlate with conformational preference or activity. Hence, the difference in activity arises from differences in their conformations, not their manner of receptor binding, suggesting that a matrix protein that differentially binds them might determine their distinct activities
Four Lessons in Versatility or How Query Languages Adapt to the Web
Exposing not only human-centered information, but machine-processable data on the Web is one of the commonalities of recent Web trends. It has enabled a new kind of applications and businesses where the data is used in ways not foreseen by the data providers. Yet this exposition has fractured the Web into islands of data, each in different Web formats: Some providers choose XML, others RDF, again others JSON or OWL, for their data, even in similar domains. This fracturing stifles innovation as application builders have to cope not only with one Web stack (e.g., XML technology) but with several ones, each of considerable complexity. With Xcerpt we have developed a rule- and pattern based query language that aims to give shield application builders from much of this complexity: In a single query language XML and RDF data can be accessed, processed, combined, and re-published. Though the need for combined access to XML and RDF data has been recognized in previous work (including the W3Cās GRDDL), our approach differs in four main aspects: (1) We provide a single language (rather than two separate or embedded languages), thus minimizing the conceptual overhead of dealing with disparate data formats. (2) Both the declarative (logic-based) and the operational semantics are unified in that they apply for querying XML and RDF in the same way. (3) We show that the resulting query language can be implemented reusing traditional database technology, if desirable. Nevertheless, we also give a unified evaluation approach based on interval labelings of graphs that is at least as fast as existing approaches for tree-shaped XML data, yet provides linear time and space querying also for many RDF graphs. We believe that Web query languages are the right tool for declarative data access in Web applications and that Xcerpt is a significant step towards a more convenient, yet highly efficient data access in a āWeb of Dataā
āExcellence R Usā: university research and the fetishisation of excellence
The rhetoric of āexcellenceā is pervasive across the academy. It is used to refer to research outputs as well as researchers, theory and education, individuals and organisations, from art history to zoology. But does āexcellenceā actually mean anything? Does this pervasive narrative of āexcellenceā do any good? Drawing on a range of sources we interrogate āexcellenceā as a concept and find that it has no intrinsic meaning in academia. Rather it functions as a linguistic interchange mechanism. To investigate whether this linguistic function is useful we examine how the rhetoric of excellence combines with narratives of scarcity and competition to show that the hypercompetition that arises from the performance of āexcellenceā is completely at odds with the qualities of good research. We trace the roots of issues in reproducibility, fraud, and homophily to this rhetoric. But we also show that this rhetoric is an internal, and not primarily an external, imposition. We conclude by proposing an alternative rhetoric based on soundness and capacity-building. In the final analysis, it turns out that that āexcellenceā is not excellent. Used in its current unqualified form it is a pernicious and dangerous rhetoric that undermines the very foundations of good research and scholarship
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