1,274 research outputs found

    Manifolds associated with (Z2)n(Z_2)^n-colored regular graphs

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    In this article we describe a canonical way to expand a certain kind of (Z2)n+1(\mathbb Z_2)^{n+1}-colored regular graphs into closed nn-manifolds by adding cells determined by the edge-colorings inductively. We show that every closed combinatorial nn-manifold can be obtained in this way. When n≤3n\leq 3, we give simple equivalent conditions for a colored graph to admit an expansion. In addition, we show that if a (Z2)n+1(\mathbb Z_2)^{n+1}-colored regular graph admits an nn-skeletal expansion, then it is realizable as the moment graph of an (n+1)(n+1)-dimensional closed (Z2)n+1(\mathbb Z_2)^{n+1}-manifold.Comment: 20 pages with 9 figures, in AMS-LaTex, v4 added a new section on reconstructing a space with a (Z2)n(Z_2)^n-action for which its moment graph is a given colored grap

    Systematic processes of land use/land cover change to identify relevant driving forces: Implications on water quality

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    Land use and land cover (LULC) are driving forces that potentially exert pressures on water bodies, which are most commonly quantified by simply obtained aggregated data. However, this is insufficient to detect the drivers that arise from the landscape change itself. To achieve this objective one must distinguish between random and systematic transitions and identify the transitions that show strong signals of change, since these will make it possible to identify the transitions that have evolved due to population growth, industrial expansion and/or changes in land management policies. Our goal is to describe a method to characterize driving forces both from LULC and dominant LULC changes, recognizing that the presence of certain LULC classes as well as the processes of transition to other uses are both sources of stress with potential effects on the condition of water bodies. This paper first quantifies the driving forces from LULC and also from processes of LULC change for three nested regions within the Mondego river basin in 1990, 2000 and 2006. It then discusses the implications for the environmental water body condition and management policies. The fingerprint left on the landscape by some of the dominant changes found, such as urbanization and industrial expansion, is, as expected, low due to their proportion in the geographic regions under study, yet their magnitude of change and consistency reveal strong signals of change regarding the pressures acting in the system. Assessing dominant LULC changes is vital for a comprehensive study of driving forces with potential impacts on water condition.The present study was carried using means provided by the research projects RECONNECT (PTDC/MAR/64627/2006), WISER (FP7-ENV-2008-226273), and 3M-RECITAL (LTER/BIA-BEC/0019/ 2009). Additionally, it benefited from two grants attributed by the FCT (Portuguese National Science Foundation): SFRH/BD/74804/ 2010 and SFRH/BPD/82127/2011

    Dashboard Executive Information System Pada Banjar Berbasis Web

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    Teknologi komputer selalu berkembang sampai pada saat ini. Komputer biasanya digunakan untuk mencari hiburan, membuat riset, dan melakukan pekerjaan. Saat ini hampir semua komputer digunakan oleh Perusahaan-Perusahaan dalam melakukan pekerjaannya. Pengguna komputer dalam melakukan pekerjaannya dibantu dengan perangkat lunak sehingga dapat menyelesaikan pekerjaan dengan cepat. Di dalam sebuah banjar ketersediaan informasi dan kemampuan dalam mengolah data secara efektif merupakan keperluan yang sangat penting dalam organisasi karena keberhasilan dari suatu organisasi tergantung pada tersedianya informasi yang dibutuhkan dan bagaimana cara-cara pemenuhan kebutuhan informasi tersebut. Pada beberapa banjar sekarang sudah menggunakan sistem yang terkomputerisasi tetapi masih sangat sederhana. Dashboard Information system merupakan sistem informasi yang menampilkan data secara visual. Dengan menggunakan dashboard diharapkan dapat mempermudah dan membantu penampilan data-data yang ada pada banjar

    Predictors of Puma Occupancy Indicate Prey Vulnerability is More Important Than Prey Availability in a Highly Fragmented Landscape

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    Habitat fragmentation represents the single greatest conservation challenge of the 21st century. This problem is particularly acute for large, obligate carnivores like pumas Puma concolor which have persisted in North and South America in the face of habitat fragmentation and other anthropogenic disturbances. Shrinking habitat and reduced connectivity mean that mapping habitat is increasingly important for species conservation in multiple-use landscapes. Previous work suggests that pumas occupy habitats where sufficient stalking cover and preferred prey are present, yet the intersection of these factors has rarely been assessed. Here we used data from 68 299 camera trap nights collected from 181 sites throughout the San Francisco Bay Area over a four-year period to identify key predictors of habitat occupancy for pumas and their primary prey (mule deer Odocoileus hemionus). Our goal was to determine whether pumas occupy habitats based on relative measures of prey availability (detection frequency), or ease of predation (density of stalking cover) and whether these predictors changed between seasons. Our results indicated that pumas primarily occupied forested habitats and did not choose habitats with abundant deer. Instead, pumas preferentially occupy habitats that facilitate their stalk and ambush hunting strategy, rather than higher prey densities, per se. The best occupancy models for mule deer indicated the importance of roads and shrub cover. However, even the best deer models performed poorly compared to the puma models, likely due to the ubiquity of mule deer in the region. Although prey density is a widely accepted correlate of habitat quality for many carnivores, our results suggest that structural elements of habitat may be a more important variable in predicting habitat use by large stalk and ambush predators like pumas, which has important implications for conservation success

    Suppressing Unwanted Memories Reduces Their Unintended Influences

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    The ability to control unwanted memories is critical for maintaining cognitive function and mental health. Prior research has shown that suppressing the retrieval of unwanted memories impairs their retention, as measured on intentional (direct) memory tests. Here we review emerging evidence revealing that retrieval suppression can also reduce the unintended influence of suppressed traces. In particular, retrieval suppression (1) gradually diminishes the tendency for memories to intrude into awareness, and (2) reduces memories’ unintended expressions on indirect memory tests. We present a neural account in which, during suppression, retrieval cues elicit hippocampally-triggered neocortical activity that briefly reinstates features of the original event, which, in turn, are suppressed by targeted neocortical and hippocampal inhibition. This reactivation-dependent reinstatement principle could provide a broad mechanism by which suppressing retrieval of intrusive memories limits their indirect influences

    OD26 - Inverse consistency error as a validation metric for deformable image registration: preliminary implementation research

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    The aim of this work is to develop a novel automatic voxel-based quantitative measurement approach to evaluate the registration accuracy of a Deformable Image Registration (DIR) algorithm in clinical practice. As the Inverse Consistency Error (ICE) can be computed directly from the deformation vector field (DVF) generated by the Treatment Planning System (TPS), it appears to be a valid surrogate of standard quality assurance metrics to assess the spatial error in the registration process
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