Carbon nanotubes in neural interfacing applications

Carbon nanotubes (CNT) are remarkable materials with a simple and inert molecular structure that gives rise to a range of potentially valuable physical and electronic properties, including high aspect ratio, high mechanical strength and excellent electrical conductivity. This review summarizes recent research on the application of CNT-based materials to study and control cells of the nervous system. It includes the use of CNT as cell culture substrates, to create patterned surfaces and to study cell–matrix interactions. It also summarizes recent investigations of CNT toxicity, particularly as related to neural cells. The application of CNT-based materials to directing the differentiation of progenitor and stem cells toward neural lineages is also discussed. The emphasis is on how CNT surface chemistry and nanotopography can be altered, and how such changes can affect neural cell function. This knowledge can be applied to creating improved neural interfaces and devices, as well as providing new approaches to neural tissue engineering and regeneration.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90821/1/1741-2552_8_1_011001.pd

Swift follow-up of IceCube triggers, and implications for the Advanced-LIGO era

Between 2011 March and 2014 August Swift responded to 20 triggers from the IceCube neutrino observatory, observing the IceCube 50% confidence error circle in X-rays, typically within 5 hours of the trigger. No confirmed counterpart has been detected. We describe the Swift follow up strategy and data analysis and present the results of the campaign. We discuss the challenges of distinguishing the X-ray counterpart to a neutrino trigger from serendipitous uncatalogued X-ray sources in the error circle, and consider the implications of our results for future strategies for multi-messenger astronomy, with particular reference to the follow up of gravitational wave triggers from the advanced-era detectors.Comment: Accepted for publication in MNRAS. 18 pages, including 8 figures and 4 tables; two of which are landscape-oriente

Connecting brain and behavior in clinical neuroscience: A network approach

In recent years, there has been an increase in applications of network science in many different fields. In clinical neuroscience and psychopathology, the developments and applications of network science have occurred mostly simultaneously, but without much collaboration between the two fields. The promise of integrating these network applications lies in a united framework to tackle one of the fundamental questions of our time: how to understand the link between brain and behavior. In the current overview, we bridge this gap by introducing conventions in both fields, highlighting similarities, and creating a common language that enables the exploitation of synergies. We provide research examples in autism research, as it accurately represents research lines in both network neuroscience and psychological networks. We integrate brain and behavior not only semantically, but also practically, by showcasing three methodological avenues that allow to combine networks of brain and behavioral data. As such, the current paper offers a stepping stone to further develop multi-modal networks and to integrate brain and behavior

Building Bridges with Boats: Preserving Community History through Intra- and Inter-Institutional Collaboration

This chapter discusses Launching through the Surf: The Dory Fleet of Pacific City, a project which documents the historical and contemporary role of dory fishers in the life of the coastal village of Pacific City, Oregon, U.S. Linfield College’s Department of Theatre and Communication Arts, its Jereld R. Nicholson Library, the Pacific City Arts Association, the Pacific City Dorymen\u27s Association, and the Linfield Center for the Northwest joined forces to engage in a collaborative college and community venture to preserve this important facet of Oregon’s history. Using ethnography as a theoretical grounding and oral history as a method, the project utilized artifacts from the dory fleet to augment interview data, and faculty/student teams created a searchable digital archive available via open access. The chapter draws on the authors’ experiences to identify a philosophy of strategic collaboration. Topics include project development and management, assessment, and the role of serendipity. In an era of value-added services where libraries need to continue to prove their worth, partnering with internal and external entities to create content is one way for academic libraries to remain relevant to agencies that do not have direct connections to higher education. This project not only developed a positive “town and gown” relationship with a regional community, it also benefited partner organizations as they sought to fulfill their missions. The project also serves as a potential model for intra- and inter-agency collaboration for all types of libraries

Lowering IceCube’s energy threshold for point source searches in the southern sky

Observation of a point source of astrophysical neutrinos would be a "smoking gun" signature of a cosmic-ray accelerator. While IceCube has recently discovered a diffuse flux of astrophysical neutrinos, no localized point source has been observed. Previous IceCube searches for point sources in the southern sky were restricted by either an energy threshold above a few hundred TeV or poor neutrino angular resolution. Here we present a search for southern sky point sources with greatly improved sensitivities to neutrinos with energies below 100 TeV. By selecting charged-current nu(mu) interacting inside the detector, we reduce the atmospheric background while retaining efficiency for astrophysical neutrino-induced events reconstructed with sub-degree angular resolution. The new event sample covers three years of detector data and leads to a factor of 10 improvement in sensitivity to point sources emitting below 100 TeV in the southern sky. No statistically significant evidence of point sources was found, and upper limits are set on neutrino emission from individual sources. A posteriori analysis of the highest-energy (similar to 100 TeV) starting event in the sample found that this event alone represents a 2.8 sigma deviation from the hypothesis that the data consists only of atmospheric background

Observation and Characterization of a Cosmic Muon Neutrino Flux from the Northern Hemisphere using six years of IceCube data

The IceCube Collaboration has previously discovered a high-energy astrophysical neutrino flux using neutrino events with interaction vertices contained within the instrumented volume of the IceCube detector. We present a complementary measurement using charged current muon neutrino events where the interaction vertex can be outside this volume. As a consequence of the large muon range the effective area is significantly larger but the field of view is restricted to the Northern Hemisphere. IceCube data from 2009 through 2015 have been analyzed using a likelihood approach based on the reconstructed muon energy and zenith angle. At the highest neutrino energies between 191 TeV and 8.3 PeV a significant astrophysical contribution is observed, excluding a purely atmospheric origin of these events at $5.6\,\sigma$ significance. The data are well described by an isotropic, unbroken power law flux with a normalization at 100 TeV neutrino energy of $\left(0.90^{+0.30}_{-0.27}\right)\times10^{-18}\,\mathrm{GeV^{-1}\,cm^{-2}\,s^{-1}\,sr^{-1}}$ and a hard spectral index of $\gamma=2.13\pm0.13$. The observed spectrum is harder in comparison to previous IceCube analyses with lower energy thresholds which may indicate a break in the astrophysical neutrino spectrum of unknown origin. The highest energy event observed has a reconstructed muon energy of $(4.5\pm1.2)\,\mathrm{PeV}$ which implies a probability of less than 0.005% for this event to be of atmospheric origin. Analyzing the arrival directions of all events with reconstructed muon energies above 200 TeV no correlation with known $\gamma$-ray sources was found. Using the high statistics of atmospheric neutrinos we report the currently best constraints on a prompt atmospheric muon neutrino flux originating from charmed meson decays which is below $1.06$ in units of the flux normalization of the model in Enberg et al. (2008).Comment: 20 pages, 21 figure

The contribution of Fermi-2LAC blazars to the diffuse TeV-PeV neutrino flux

The recent discovery of a diffuse cosmic neutrino flux extending up to PeV energies raises the question of which astrophysical sources generate this signal. One class of extragalactic sources which may produce such high-energy neutrinos are blazars. We present a likelihood analysis searching for cumulative neutrino emission from blazars in the 2nd Fermi-LAT AGN catalogue (2LAC) using an IceCube neutrino dataset 2009-12 which was optimised for the detection of individual sources. In contrast to previous searches with IceCube, the populations investigated contain up to hundreds of sources, the largest one being the entire blazar sample in the 2LAC catalogue. No significant excess is observed and upper limits for the cumulative flux from these populations are obtained. These constrain the maximum contribution of the 2LAC blazars to the observed astrophysical neutrino flux to be $27 \%$ or less between around 10 TeV and 2 PeV, assuming equipartition of flavours at Earth and a single power-law spectrum with a spectral index of $-2.5$. We can still exclude that the 2LAC blazars (and sub-populations) emit more than $50 \%$ of the observed neutrinos up to a spectral index as hard as $-2.2$ in the same energy range. Our result takes into account that the neutrino source count distribution is unknown, and it does not assume strict proportionality of the neutrino flux to the measured 2LAC $\gamma$-ray signal for each source. Additionally, we constrain recent models for neutrino emission by blazars.Comment: 18 pages, 22 figure

All-sky search for time-integrated neutrino emission from astrophysical sources with 7 years of IceCube data

Since the recent detection of an astrophysical flux of high energy neutrinos, the question of its origin has not yet fully been answered. Much of what is known about this flux comes from a small event sample of high neutrino purity, good energy resolution, but large angular uncertainties. In searches for point-like sources, on the other hand, the best performance is given by using large statistics and good angular reconstructions. Track-like muon events produced in neutrino interactions satisfy these requirements. We present here the results of searches for point-like sources with neutrinos using data acquired by the IceCube detector over seven years from 2008--2015. The discovery potential of the analysis in the northern sky is now significantly below $E_\nu^2d\phi/dE_\nu=10^{-12}\:\mathrm{TeV\,cm^{-2}\,s^{-1}}$, on average $38\%$ lower than the sensitivity of the previously published analysis of four years exposure. No significant clustering of neutrinos above background expectation was observed, and implications for prominent neutrino source candidates are discussed.Comment: 19 pages, 17 figures, 3 tables; ; submitted to The Astrophysical Journa