1,721,332 research outputs found
Overall Survival Prediction of Glioma Patients With Multiregional Radiomics
Get PDFRadiomics-guided prediction of overall survival (OS) in brain gliomas is seen as a significant problem in Neuro-oncology. The ultimate goal is to develop a robust MRI-based approach (i.e., a radiomics model) that can accurately classify a novel subject as a short-term survivor, a medium-term survivor, or a long-term survivor. The BraTS 2020 challenge provides radiological imaging and clinical data (178 subjects) to develop and validate radiomics-based methods for OS classification in brain gliomas. In this study, we empirically evaluated the efficacy of four multiregional radiomic models, for OS classification, and quantified the robustness of predictions to variations in automatic segmentation of brain tumor volume. More specifically, we evaluated four radiomic models, namely, the Whole Tumor (WT) radiomics model, the 3-subregions radiomics model, the 6-subregions radiomics model, and the 21-subregions radiomics model. The 3-subregions radiomics model is based on a physiological segmentation of whole tumor volume (WT) into three non-overlapping subregions. The 6-subregions and 21-subregions radiomic models are based on an anatomical segmentation of the brain tumor into 6 and 21 anatomical regions, respectively. Moreover, we employed six segmentation schemes – five CNNs and one STAPLE-fusion method – to quantify the robustness of radiomic models. Our experiments revealed that the 3-subregions radiomics model had the best predictive performance (mean AUC = 0.73) but poor robustness (RSD = 1.99) and the 6-subregions and 21-subregions radiomics models were more robust (RSD 1.39) with lower predictive performance (mean AUC 0.71). The poor robustness of the 3-subregions radiomics model was associated with highly variable and inferior segmentation of tumor core and active tumor subregions as quantified by the Hausdorff distance metric (4.4−6.5mm) across six segmentation schemes. Failure analysis revealed that the WT radiomics model, the 6-subregions radiomics model, and the 21-subregions radiomics model failed for the same subjects which is attributed to the common requirement of accurate segmentation of the WT volume. Moreover, short-term survivors were largely misclassified by the radiomic models and had large segmentation errors (average Hausdorff distance of 7.09mm). Lastly, we concluded that while STAPLE-fusion can reduce segmentation errors, it is not a solution to learning accurate and robust radiomic models
Entropy based transition analysis of eye movement on physics representational competence
No full textCanada on the Move : Discovering the Natural History of Georgian Bay
No full textThis project is made possible with funding by the Government of Ontario and through eCampusOntario’s support of the Virtual Learning Strategy.We live on the surface of a dynamic planet undergoing rapid environmental change. We need to be able to monitor and analyse these changes if we are to manage impacts. Knowledge is key and training a new generation of Canadian geoscientists to tackle environmental issues relies on educating them about the Earth’s past. Nowhere in Canada can the lessons of Earth’s past be better exemplified than at Georgian Bay where the meeting of landscapes, cultures, biomes, and geologies creates a microcosm of the effects of the natural history of environmental change.The Bay is a major tourist attraction with many recreational opportunities, close to the densest population centre in Canada, and as a result is constantly affected by the ongoing growth of urbanized areas. Great swathes of land are recognized and protected for their exceptional ecological diversity by local and international interest groups. However, the geological diversity created by 2.5 billion years of climate change, which underpins the origins of this environment, are not currently highlighted to the public. Recently, a new type of conservation, called “geoconservation” seeking to promote and protect the geological heritage of a region through the establishment of internationally recognized UNESCO Geoparks has emerged, for which Georgian Bay is an ideal candidate.A jewel of Canadian geology, Georgian Bay is the sixth and smallest Great Lake, but it's shoreline exposes the most diverse geology found anywhere in North America. Its geological diversity reflects its location astride the boundary of the Precambrian Canadian Shield where rocks are as old as 2.4 billion years old, and much younger Paleozoic fossiliferous sedimentary rocks to the south that are some 400 million years in age. These opposing shores afford great contrasts in landscape from the Thirty Thousand Island area where white pines grow out of the ancient Precambrian rocks so beloved of the Group of Seven, to the bold promontory and limestone plains of the Bruce Peninsula where the Niagara Escarpment falls dramatically into deep water. The waters of Georgian Bay are a gift of successive Ice Ages when continental ice sheets as much as 3 km thick covered Canada much like Antarctica today. Postglacial sediments on the margins and floors of the Bay preserve a record of recent dramatic lake level fluctuations, which were witnessed by indigenous people living on the dynamic shorelines. Such landscapes help inform geologists of what might lie in store in the future in a warming world.This course consists of 8 lessons with lectures, self-guided interactive learning assessments, discussion topics, and quizzes, designed to capture the natural history of Georgian Bay. Foundational geologic knowledge is used to interpret the rock and sediment record and illustrate how it can be used to inform us about events in Earth’s past. By understanding this geological heritage, we can understand how to manage our natural resources going forward
Dipole-slot-dipole metasurfaces
Get PDFA complementary frequency selective surface (CFSS) can be formed on the basis of Babinet's principle. It consists of an array of slots separated from an array of dipoles by a thin dielectric substrate. This study shows that by adding an extra layer of dipoles to a CFSS capacitance can be added to the structure, which leads to a decrease in its resonant frequency. This new structure is called a dipole-slot-dipole metasurface (MTS) and it has unit-cell dimensions of λ/10 × λ/10 × λ/333, where λ is representing the free space wavelength. The dipole-slot-dipole MTS has been fabricated and measured. The study also reports on its equivalent circuit; and the effects of the length of the dipoles on the added layer and their alignment on the pass band resonant frequency of the dipole-slot-dipole MTS
POST 2021 CHANGING STRATEGIC DYNAMICS IN AFGHANISTAN: IMPLICATIONS FOR PAKISTAN
Get PDFThe US withdrawal from Afghanistan in 2021 changed Afghanistan\u27s strategic dynamics. The Afghan Taliban now control the whole Afghanistan and have taken some adverse measures that affect not only Pakistan but also regional and global security. After 2021, Transnational terrorist groups like Al-Qaeda, Islamic Movement of Uzbekistan (IMU), Tehrik-i-Taliban Pakistan (TTP), Islamic State Khorasan Province (ISKP), Baloch Liberation Army (BLA) and East Turkestan Islamic Movement operate in Afghanistan with greater impunity and freedom. The Afghan Taliban also welcomed India to Afghanistan after 2021 to get financial assistance and support in reconstruction and development. But India’s renewed hybrid warfare from Afghanistan has seriously jeopardised the internal security of Pakistan. Pakistan-focused groups like TTP, BLA, and ISKP suddenly got reorganised under the umbrella of India in Afghanistan. They started a vicious cycle of violence against the civil and military installations of Pakistan in Balochistan and the ex-FATA region, besides attacks on the Chinese citizens to disrupt CPEC and slow down FDI to Pakistan. This article analyses the whole debate under the regional security complex theory, which evaluates that simple physical adjacency generates more security interaction among neighbours than among states located in different areas. Adjacency is potent for security because many threats travel more easily over short distances than long ones. The RSCT aptly applies to Afghanistan’s changing strategic dynamics and regional implications, focusing on Pakistan.
Bibliography Entry
Bukhari, Syed Munib Ali and Masood Ur Rehman Khattak. 2024. " Post 2021 Changing Strategic Dynamics in Afghanistan: Implications for Pakistan." Margalla Papers 28 (1): 198-210
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Equivalent circuit model for coupled complementary metasurfaces
Get PDFCoupled complementary metasurfaces (CCMTS) exhibit a passband whose frequency is several times lower than that of the individual metasurface (MTS) passband frequency. In this paper, we explain this phenomenon and propose a simple and accurate equivalent circuit for CCMTS comprised of slots and their Babinet complement, dipoles. An equivalent circuit is extracted from a coupled EFIE-MFIE equation using a synthetic basis function. The same procedure can be conveniently applied to any CCMTS. The model allows one to estimate the large downshift of resonant frequency and the bandwidth utilizing a simple formula. When used in a subresonant regime, the unit cell may have a dimension of a tenth of a free space wavelength with a moderate value of permittivity between the complementary layers
- …
