Reducing variability in along-tract analysis with diffusion profile realignment

Diffusion weighted MRI (dMRI) provides a non invasive virtual reconstruction of the brain's white matter structures through tractography. Analyzing dMRI measures along the trajectory of white matter bundles can provide a more specific investigation than considering a region of interest or tract-averaged measurements. However, performing group analyses with this along-tract strategy requires correspondence between points of tract pathways across subjects. This is usually achieved by creating a new common space where the representative streamlines from every subject are resampled to the same number of points. If the underlying anatomy of some subjects was altered due to, e.g. disease or developmental changes, such information might be lost by resampling to a fixed number of points. In this work, we propose to address the issue of possible misalignment, which might be present even after resampling, by realigning the representative streamline of each subject in this 1D space with a new method, coined diffusion profile realignment (DPR). Experiments on synthetic datasets show that DPR reduces the coefficient of variation for the mean diffusivity, fractional anisotropy and apparent fiber density when compared to the unaligned case. Using 100 in vivo datasets from the HCP, we simulated changes in mean diffusivity, fractional anisotropy and apparent fiber density. Pairwise Student's t-tests between these altered subjects and the original subjects indicate that regional changes are identified after realignment with the DPR algorithm, while preserving differences previously detected in the unaligned case. This new correction strategy contributes to revealing effects of interest which might be hidden by misalignment and has the potential to improve the specificity in longitudinal population studies beyond the traditional region of interest based analysis and along-tract analysis workflows.Comment: v4: peer-reviewed round 2 v3 : deleted some old text from before peer-review which was mistakenly included v2 : peer-reviewed version v1: preprint as submitted to journal NeuroImag

Remediation of Distressed Frozen Earth Cofferdams

Artificial Ground Freezing was used to provide temporary earth support and groundwater control for a complex system of three frozen earth cofferdams for the Milwaukee Metropolitan Sewer District’s Harbor Siphons Project in Milwaukee, Wisconsin. Site geometry and frozen earth structural design precluded construction of one large excavation, requiring the component system of the tangential cofferdams. High groundwater velocity prevented the formation of the frozen earth walls during various stages of the project. Remedial methods including external dewatering, permeation grouting, jet grouting, timber shoring and sheet piling were attempted to complete the project. Ultimately a more aggressive ground freezing program was implemented and the project was successfully excavated. The design of the ground freezing system is presented, as well as the difficulties encountered with the high ground water velocity and its impact on freezing. The failed remedial approaches are discussed in detail, including lessons learned. A description of the aggressive ground freezing approach is included as it was the final solution to a complex problem of site geometry and unexpected groundwater conditions

Cross-cultural perspectives of LGBTQ psychology from five different countries: current state and recommendations

Lesbian, gay, bisexual, transgender and queer or questioning psychology (LGBTQ psychology) is a branch of psychology that promotes inclusiveness in theory and practice across the science of psychology, affirming the lives of people with different sexual orientations and forms of gender expression in a non-heterosexist and non-genderist perspective. This article highlights the historical development of LGBTQ psychology in the context of different realities for LGBTQ people in five different countries (Russia, Greece, Colombia, South Africa and the province of Quebec, Canada). Key experts on LGBTQ concerns report distinctive challenges they have faced when promoting LGBTQ rights and developing LGBTQ psychology (e.g., the pathologization and criminalization of sexual diversity, neglect on the part of authorities, and rejection from religious groups). Human and mental health sciences have played an important role in the blossoming of LGBTQ psychology. Cross-cultural narratives show that the recognition of lesbian and gay rights comes before the recognition of the rights of bi, trans, queer and questioning people. Various forms of homonegativity and transphobia still coexist even in countries that have established protections and rights recognition for LGBTQ people. We provide 15 strategies to help psychological organizations and psychologists around the world promote the development of LGBTQ psychology

Social learning against data falsification in sensor networks

Sensor networks generate large amounts of geographically-distributed data. The conventional approach to exploit this data is to first gather it in a special node that then performs processing and inference. However, what happens if this node is destroyed, or even worst, if it is hijacked? To explore this problem, in this work we consider a smart attacker who can take control of critical nodes within the network and use them to inject false information. In order to face this critical security thread, we propose a novel scheme that enables data aggregation and decision-making over networks based on social learning, where the sensor nodes act resembling how agents make decisions in social networks. Our results suggest that social learning enables high network resilience, even when a significant portion of the nodes have been compromised by the attacker

Some Applications of the Extended Bendixson-Dulac Theorem

During the last years the authors have studied the number of limit cycles of several families of planar vector fields. The common tool has been the use of an extended version of the celebrated Bendixson-Dulac Theorem. The aim of this work is to present an unified approach of some of these results, together with their corresponding proofs. We also provide several applications.Comment: 19 pages, 3 figure

CrO2: a self-doped double exchange ferromagnet

Band structure calculations of CrO2 carried out in the LSDA+U approach reveal a clear picture of the physics behind the metallic ferromagnetic properties. Arguments are presented that the metallic ferromagnetic oxide CrO2 belongs to a class of materials in which magnetic ordering exists due to double exchange (in this respect CrO2 turns out to be similar to the CMR manganates). It is concluded that CrO2 has small or even negative charge transfer gap which can result in self-doping. Certain experiments to check the proposed picture are suggested.Comment: 4 pages, 4 Figure

Imaging of joints with laser‐based photoacoustic tomography: An animal study

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/134964/1/mp4166.pd

Band-width control in a perovskite-type 3d^1 correlated metal Ca_1-xSr_xVO_3. II. Optical spectroscopy investigation

Optical conductivity spectra of single crystals of Ca_1-xSr_xVO_3 have been studied to elucidate how the electronic behavior depends on the strength of the electron correlation without changing the nominal number of electrons per vanadium atom. The effective mass deduced by the analysis of the Drude-like contribution do not show critical enhancement, even though the system is close to the Mott transition. Besides the Drude-like contribution, two anomalous features were observed in the optical conductivity spectra of the intraband transition within the 3d band. These features can be assigned to transitions involving the incoherent and coherent bands near the Fermi level. The large spectral weight redistribution in this system, however, does not involve a large mass enhancement.Comment: 12 pages in a Phys. Rev. B camera-ready format with 16 EPS figures embedded. LaTeX 2.09 source file using "camera.sty" and "prbplug.sty" provided by N. Shirakawa. For OzTeX (Macintosh), use "ozfig.sty" instead of "psfig.sty". "ozfig.sty" can be also obtained by e-mail request to N. Shirakawa: . Submitted to Phys. Rev. B. See "Part I (by Inoue et al.)" at cond-mat/980107