259 research outputs found
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Augmenting Wiring Diagrams of Neural Circuits with Activity in Larval Drosophila
Neural circuit models explain an animal's behavior as evoked activity of different circuit elements of its nervous system.
Synaptic wiring diagrams mapped from structural imaging of nervous systems guide modeling of neural circuits on the basis of connectivity.
However, connectivity alone may not sufficiently constrain the set of plausible circuit hypotheses for empirical study.
Combining structural imaging of synaptic connectivity with functional information from activity imaging can further constrain these hypotheses to create unequivocal neural circuit models.
This thesis develops computational methods and tools to cross-reference structural and activity imaging of explant larval Drosophila central nervous systems at cellular resolution.
Augmenting synaptic wiring diagrams with activity maps via these methods relates circuit structure and function at the neuronal level on a per-behavior basis.
Neuronal activity of larval central nervous systems expressing pan-neuronal calcium indicators is imaged in a light sheet microscope, which are then structurally imaged with high throughput electron microscopy.
Methods and tools are provided for the assembly of these image volumes, spatial registration between imaging modalities, automated detection of relevant tissue and cellular structures in each, extraction of activity time series, and morphological identification of neurons in structural imaging using reference wiring diagrams mapped from other larvae.
Using these methods, existing wiring diagrams mapped from a reference first instar larva were identified with neurons in a larva augmented with activity information for a neural circuit involved in peristaltic motor control.
This demonstrates the feasibility of the contributed methods to associate the wiring diagrams of arbitrary circuits of interest with activity timeseries across multiple individuals, behaviors, and behavioral bouts.
To demonstrate capability to augment wiring diagrams with information besides activity, these methods are also applied to multiple larvae each expressing specific neurotransmitter labels rather than calcium indicators in the light sheet microscopy.
This work scaffolds future modeling of circuits underlying behavior that can only be mechanistically understood in the context of multi-modal observation of synaptic connectivity, functional activity and molecular markers.
The methods developed also enable comparative connectomics between multiple individuals, which is necessary to study inter-individual variability in circuits and to observe experimental intervention in the development, structure, and function of neural circuits.Howard Hughes Medical Institute Janelia Research Campu
Constant Scalar Curvature Metrics on Boundary Complexes of Cyclic Polytopes
In [7], a notion of constant scalar curvature metrics on piecewise flat
manifolds is defined. Such metrics are candidates for canonical metrics on
discrete manifolds. In this paper, we define a class of vertex transitive
metrics on certain triangulations of ; namely, the boundary
complexes of cyclic polytopes. We use combinatorial properties of cyclic
polytopes to show that, for any number of vertices, these metrics have constant
scalar curvature.Comment: 15 pages, 4 figure
Application of neural networks and sensitivity analysis to improved prediction of trauma survival
Application of neural networks and sensitivity analysis to improved prediction of trauma surviva
Insights into the evolution of the Thomson Orogen from geochronology, geochemistry, and zircon isotopic studies of magmatic rocks
Zircon UâPb ages, ΔHf(t), and ÎŽ18O isotopic data together with geochemistry and limited SmâNd results from magmatic rocks sampled in deep-basement drill cores from undercover parts of the Thomson Orogen provide strong temporal links with outcropping regions of the orogen and important clues to its evolution and relationship with the Lachlan Orogen. SHRIMP UâPb zircon ages show that magmatism of Early Ordovician age is widespread across the central, undercover regions of the Thomson Orogen and occurred in a narrow time-window between 480 and 470âMa. These rocks have evolved ΔHf(t)zrn (â12.18 to â6.26) and ΔNd (â11.3 to â7.1), and supracrustal ÎŽ18Ozrn (7.01â8.50â°), which is in stark contrast to Early Ordovician magmatic rocks in the Lachlan Orogen that are isotopically juvenile. Two samples have late Silurian ages (425â420âMa), and four have Devonian ages (408â382âMa). The late Silurian rocks have evolved ΔHf(t)zrn (â6.42 to â4.62) and supracrustal ÎŽ18Ozrn (9.26â10.29â°) values, while the younger Devonian rocks show a shift toward more juvenile ΔHf(t)zrn, a trend that is also seen in rocks of this age in the Lachlan Orogen. Interestingly, two early Late Devonian samples have juvenile ΔHf(t)zrn (0.01â1.92) but supracrustal ÎŽ18Ozrn (7.45â8.77â°) indicating rapid recycling of juvenile material. Two distinct HfâO isotopic mixing trends are observed for magmatic rocks of the Thomson Orogen. One trend appears to have incorporated a more evolved supracrustal component and is defined by samples from the northern two-thirds of the Thomson Orogen, while the other trend is generally less evolved and from samples in the southern third of the Thomson Orogen and matches the isotopic character of rocks from the Lachlan Orogen. The spatial association of the Early Ordovician magmatism with the more evolved metasedimentary signature suggests that at least the northern part of the Thomson Orogen is underlain by older pre-Delamerian metasedimentary rocks
2018 Student Composers Recital
The 2018 Student Composers Recital features performances of works created by KSU student composers with direction from Composer-in-Residence, Dr. Laurence Sherr.https://digitalcommons.kennesaw.edu/musicprograms/2046/thumbnail.jp
Institutional theory and sustainable energy practices 1 An Institutional Theory Perspective on Sustainable Practices across the Dairy Supply Chain
Institutional theory and sustainable energy practices 2 An Institutional Theory perspective on sustainable practices across the dairy supply chain Abstract The need for sustainable practices in the food supply chain, particularly in the area of energy reduction, is becoming acute. The food industry currently has to contend with multiple competing pressures alongside the new challenges of sustainable production. We applied Institutional Theory to explore the role of supermarkets in the development of legitimate sustainable practices across the dairy supply chains. The paper focuses on dairy supply chain organizations and their consumption of energy. We conducted 70 semi-structured telephone interviews with various stakeholders across the supply chain. Findings revealed that the majority of actors in the supply chain identified supermarkets as the dominant player, and that the supermarkets exert pressure on other smaller organizations across the supply chain that. Although some organizations wished to pursue a sustainable agenda through integrating new rules and legitimate practices within their own organization, the dominant logic appeared to be one of cost reduction and profit maximization. There was also evidence that supermarkets and other large organizations attempt to replicate publically available information on green successes for imagery purposes. We conclude that the dominant logic of cost reduction is so well established that challenging the dominant logic may prove difficult. The challenge is therefore to complement the dominant logic with sustainable practices across the whole supply chain, a role Government needs to play. This will require a broader more systemic approach to encouraging sustainable practices including investment and financing practices, so that all members of the dairy supply chain can co-operate and contribute to energy reduction
Deoxyfluorination using CuF2 : enabled by a Lewis base activating group strategy
We thank the University of St Andrews for PhD studentships (D.E.S and S.C.), GlaxoSmithKline and the University of Glasgow for financial support.Deoxyfluorination is a primary method for the formation of CâF bonds. Bespoke reagents are commonly used due to issues associated with the low reactivity of metal fluorides. Here, we report the development of a simple strategy for deoxyfluorination using firstârow transition metal fluorides that overcomes these limitations. Using CuF2 as an exemplar, activation of an O âalkylisourea adduct formed in situ allows effective nucleophilic fluoride transfer to a range of primary and secondary alcohols. Spectroscopic investigations have been used to probe the origin of the enhanced reactivity of CuF2 . The utility of the process towards enabling 18Fâradiolabeling is also presented.PostprintPeer reviewe
A case study on reviewing specialist services commissioning in Wales: TAVI for Severe Aortic Stenosis
The Welsh Health Specialised Services Committee (WHSSC) is responsible for planning, commissioning and funding specialised healthcare in Wales. Investment in new technologies or services is based on clinical and economic evidence, using a consistent and transparent process. This is accomplished in three stages. The first stage is the preparation of a rapid evidence review. This then informs the development or update of the relevant Commissioning Policy. The final stage is to prioritise the Commissioning Policy recommendations against all other new services and interventions, to inform WHSSCâs annual commissioning intentions. In 2017, a review was conducted of the WHSSC Commissioning Policy for transcatheter aortic valve implantation for severe aortic stenosis. Prior to this only high-risk patients were eligible for transcatheter aortic valve implantation. The rapid evidence review identified three randomised controlled trials and two economic analyses relevant to the decision problem. Transcatheter aortic valve implantation was generally found to be more expensive and more effective than medical management or surgical aortic valve replacement, with incremental cost-effectiveness ratios around ÂŁ10,500âÂŁ36,000 for inoperable groups and ÂŁ17,000âÂŁ24,000 in high-risk groups. The rapid evidence review, expert advice and stakeholder feedback informed the revision process of the Commissioning Policy for transcatheter aortic valve implantation. This recommended the addition of patients unsuitable for surgical aortic valve replacement and the removal of explicit risk scoring. This recommendation was subject to the prioritisation process (carried out annually). The updated transcatheter aortic valve implantation recommendation was ranked second out of 23 technologies and services competing for additional WHSSC funding. The WHSSC Integrated Commissioning Plan for specialised services in Wales (2019) therefore included funding to support the new criteria for transcatheter aortic valve implantation treatment
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