3,219 research outputs found

    Visibility Representations of Boxes in 2.5 Dimensions

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    We initiate the study of 2.5D box visibility representations (2.5D-BR) where vertices are mapped to 3D boxes having the bottom face in the plane z=0z=0 and edges are unobstructed lines of sight parallel to the xx- or yy-axis. We prove that: (i)(i) Every complete bipartite graph admits a 2.5D-BR; (ii)(ii) The complete graph KnK_n admits a 2.5D-BR if and only if n19n \leq 19; (iii)(iii) Every graph with pathwidth at most 77 admits a 2.5D-BR, which can be computed in linear time. We then turn our attention to 2.5D grid box representations (2.5D-GBR) which are 2.5D-BRs such that the bottom face of every box is a unit square at integer coordinates. We show that an nn-vertex graph that admits a 2.5D-GBR has at most 4n6n4n - 6 \sqrt{n} edges and this bound is tight. Finally, we prove that deciding whether a given graph GG admits a 2.5D-GBR with a given footprint is NP-complete. The footprint of a 2.5D-BR Γ\Gamma is the set of bottom faces of the boxes in Γ\Gamma.Comment: Appears in the Proceedings of the 24th International Symposium on Graph Drawing and Network Visualization (GD 2016

    Gray-matter volume, midbrain dopamine D2/D3 receptors and drug craving in methamphetamine users.

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    Dysfunction of the mesocorticolimbic system has a critical role in clinical features of addiction. Despite evidence suggesting that midbrain dopamine receptors influence amphetamine-induced dopamine release and that dopamine is involved in methamphetamine-induced neurotoxicity, associations between dopamine receptors and gray-matter volume have been unexplored in methamphetamine users. Here we used magnetic resonance imaging and [(18)F]fallypride positron emission tomography, respectively, to measure gray-matter volume (in 58 methamphetamine users) and dopamine D2/D3 receptor availability (binding potential relative to nondisplaceable uptake of the radiotracer, BPnd) (in 31 methamphetamine users and 37 control participants). Relationships between these measures and self-reported drug craving were examined. Although no difference in midbrain D2/D3 BPnd was detected between methamphetamine and control groups, midbrain D2/D3 BPnd was positively correlated with gray-matter volume in the striatum, prefrontal cortex, insula, hippocampus and temporal cortex in methamphetamine users, but not in control participants (group-by-midbrain D2/D3 BPnd interaction, P<0.05 corrected for multiple comparisons). Craving for methamphetamine was negatively associated with gray-matter volume in the insula, prefrontal cortex, amygdala, temporal cortex, occipital cortex, cerebellum and thalamus (P<0.05 corrected for multiple comparisons). A relationship between midbrain D2/D3 BPnd and methamphetamine craving was not detected. Lower midbrain D2/D3 BPnd may increase vulnerability to deficits in gray-matter volume in mesocorticolimbic circuitry in methamphetamine users, possibly reflecting greater dopamine-induced toxicity. Identifying factors that influence prefrontal and limbic volume, such as midbrain BPnd, may be important for understanding the basis of drug craving, a key factor in the maintenance of substance-use disorders

    L-Visibility Drawings of IC-planar Graphs

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    An IC-plane graph is a topological graph where every edge is crossed at most once and no two crossed edges share a vertex. We show that every IC-plane graph has a visibility drawing where every vertex is an L-shape, and every edge is either a horizontal or vertical segment. As a byproduct of our drawing technique, we prove that an IC-plane graph has a RAC drawing in quadratic area with at most two bends per edge

    3D Visibility Representations of 1-planar Graphs

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    We prove that every 1-planar graph G has a z-parallel visibility representation, i.e., a 3D visibility representation in which the vertices are isothetic disjoint rectangles parallel to the xy-plane, and the edges are unobstructed z-parallel visibilities between pairs of rectangles. In addition, the constructed representation is such that there is a plane that intersects all the rectangles, and this intersection defines a bar 1-visibility representation of G.Comment: Appears in the Proceedings of the 25th International Symposium on Graph Drawing and Network Visualization (GD 2017

    PRAKTIK PENYELESAIAN TINDAK PIDANA YANG DILAKUKAN OLEH ANAK DENGAN PENDEKATAN RESTORATIVE JUSTICE DI POLRES KOTA SUKABUMI

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    Anak merupakan sumber daya manusia sebagai penerus generasi yang akan datang. Pemidanaan terhadap anak sebagai pelaku tindak pidana bukanlah hal yang tepat diterapkan. Karenanya, dibutuhkan pendekatan baru yakni Restorative Justice yang dianggap menjadi salah satu jawaban dalam penanggulangan banyaknya tindak pidana. Pelaksanaan Restorative Justice diatur dalam Undang – Undang Nomor 11 Tahun 2012 tentang Sistem Peradilan Pidana Anak. Pelaksanaan Pendekatan Restorative Justice dilaksanakan dalam upaya yang disebut upaya Diversi. Upaya diversi ini wajib dilaksanakan dalam tahapan penyidikan, penuntutan dan pemeriksaan anak di pengadilan negeri. Berdasarkan uraian tersebut penulis tertarik melakukan penulisan hukum dengan permasalahan penelitian mengenai pelaksanaan penyelesaian tindak pidana anak melalui pendekatan Restorative Justice menurut UU No. 11 Tahun 2012 tentang Sistem Peradilan Pidana Anak serta hambatan dan upaya Polres Kota Sukabumi dalam penanganan tindak pidana anak melalui pendekatan Restorative Justice di wilayahnya. Pendekatan penulisan hukum ini menggunakan pendekatan yuridis empiris yaitu melihat hukum dalam arti nyata. Penelitian yang digunakan dalam penulisan ini adalah deskriptif dimana penulis menggambarkan peraturan perundang – undangan yang berlaku dan diartikan dengan teori hukum serta pelaksanaan hukum positif. Berdasarkan hal tersebut penulis melakukan proses wawancara terhadap lembaga yang terlibat, diantaranya adalah Polres Kota Sukabumi sebagai lokasi penelitian. Hasil penelitian menunjukkan bahwa di Polres Kota Sukabumi telah mengupayakan proses diversi secara maksimal. Upaya yang dilakukan dimulai dari pengupayaan proses diversi itu sendiri sesuai dengan Undang – Undang Nomor 11 Tahun 2012 dan peningkatan sarana prasarana. Hambatan dalam melaksanakan proses diversi yang dihadapi oleh Polres Kota Sukabumi terkait pada beberapa masalah dari berbedanya pandangan mengenai penanganan anak hingga biaya ganti rugi dalam proses mediasi yang diajukan oleh pihak korban tidak bisa disanggupi oleh pihak pelaku

    Evolution of Landau Levels into Edge States at an Atomically Sharp Edge in Graphene

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    The quantum-Hall-effect (QHE) occurs in topologically-ordered states of two-dimensional (2d) electron-systems in which an insulating bulk-state coexists with protected 1d conducting edge-states. Owing to a unique topologically imposed edge-bulk correspondence these edge-states are endowed with universal properties such as fractionally-charged quasiparticles and interference-patterns, which make them indispensable components for QH-based quantum-computation and other applications. The precise edge-bulk correspondence, conjectured theoretically in the limit of sharp edges, is difficult to realize in conventional semiconductor-based electron systems where soft boundaries lead to edge-state reconstruction. Using scanning-tunneling microscopy and spectroscopy to follow the spatial evolution of bulk Landau-levels towards a zigzag edge of graphene supported above a graphite substrate we demonstrate that in this system it is possible to realize atomically sharp edges with no edge-state reconstruction. Our results single out graphene as a system where the edge-state structure can be controlled and the universal properties directly probed.Comment: 16 pages, 4 figure

    Chemical variation in a dominant tree species: population divergence, selection and genetic stability across environments

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    Understanding among and within population genetic variation of ecologically important plant traits provides insight into the potential evolutionary processes affecting those traits. The strength and consistency of selection driving variability in traits would be affected by plasticity in differences among genotypes across environments (G×E). We investigated population divergence, selection and environmental plasticity of foliar plant secondary metabolites (PSMs) in a dominant tree species, Eucalyptus globulus. Using two common garden trials we examined variation in PSMs at multiple genetic scales; among 12 populations covering the full geographic range of the species and among up to 60 families within populations. Significant genetic variation in the expression of many PSMs resides both among and within populations of E. globulus with moderate (e.g., sideroxylonal A h2op = 0.24) to high (e.g., macrocarpal G h2op = 0.48) narrow sense heritabilities and high coefficients of additive genetic variation estimated for some compounds. A comparison of Qst and Fst estimates suggest that variability in some of these traits may be due to selection. Importantly, there was no genetic by environment interaction in the expression of any of the quantitative chemical traits despite often significant site effects. These results provide evidence that natural selection has contributed to population divergence in PSMs in E. globulus, and identifies the formylated phloroglucinol compounds (particularly sideroxylonal) and a dominant oil, 1,8-cineole, as candidates for traits whose genetic architecture has been shaped by divergent selection. Additionally, as the genetic differences in these PSMs that influence community phenotypes is stable across environments, the role of plant genotype in structuring communities is strengthened and these genotypic differences may be relatively stable under global environmental changes

    Mobility and Maternal Position during Childbirth in Tanzania: An Exploratory Study at Four Government Hospitals.

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    Emerging research evidence suggests a potential benefit in being upright in the first stage of labour and a systematic review of trials suggests both benefits and harmful effects associated with being upright in the second stage of labour. Implementing evidence-based obstetric care in African countries with scarce resources is particularly challenging, and requires an understanding of the cumulative nature of science and commitment to applying the most up to date evidence to clinical decisions. In this study, we documented current practice rates, explored the barriers and opportunities to implementing these procedures from the provider perspective, and documented women's preferences and satisfaction with care. This was an exploratory study using quantitative and qualitative methods. Practice rates were determined by exit interviews with a consecutive sample of postnatal women. Provider views were explored using semi-structured interviews (with doctors and traditional birth attendants) and focus group discussions (with midwives). The study was conducted at four government hospitals, two in Dar es Salaam and two in the neighbouring Coast region, Tanzania. MAIN OUTCOME MEASURES: Practice rates for mobility during labour and delivery position; women's experiences, preferences and views about the care provided; and provider views of current practice and barriers and opportunities to evidence-based obstetric practice. Across all study sites more women were mobile at home (15.0%) than in the labour ward (2.9%), but movement was quite restricted at home before women were admitted to labour ward (51.6% chose to rest with little movement). Supine position for delivery was used routinely at all four hospitals; this was consistent with women's preferred choice of position, although very few women are aware of other positions. Qualitative findings suggest obstetricians and midwives favoured confining to bed during the first stage of labour, and supine position for delivery. The barriers to change appear to be complicated and require providers to want to change, and women to be informed of alternative positions during the first stage of labour and delivery. We believe that highlighting the gap between actual practice and current evidence provides a platform for dialogue with providers to evaluate the threats and opportunities for changing practice

    Brucellosis remains a neglected disease inthe developing world: a call forinterdisciplinary action

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    Brucellosis places significant burdens on the human healthcare system and limits the economic growth of individuals, communities, and nations where such development is especially important to diminish the prevalence of poverty. The implementation of public policy focused on mitigating the socioeconomic effects of brucellosis in human and animal populations is desperately needed. When developing a plan to mitigate the associated consequences, it is vital to consider both the abstract and quantifiable effects. This requires an interdisciplinary and collaborative, or One Health, approach that consists of public education, the development of an infrastructure for disease surveillance and reporting in both veterinary and medical fields, and campaigns for control in livestock and wildlife species

    Behavioural and molecular endophenotypes in psychotic disorders reveal heritable abnormalities in glutamatergic neurotransmission.

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    Psychotic disorders such as schizophrenia are biologically complex and carry huge population morbidity due to their prevalence, persistence and associated disability. Defined by features such as delusions and hallucinations, they involve cognitive dysfunction and neurotransmitter dysregulations that appear mostly to involve the dopaminergic and glutamatergic systems. A number of genetic and environmental factors are associated with these disorders but it has been difficult to identify the biological pathways underlying the principal symptoms. The endophenotype concept of stable, heritable traits that form a mechanistic link between genes and an overt expression of the disorder has potential to reduce the complexity of psychiatric phenotypes. In this study, we used a genetically sensitive design with individuals with a first episode of psychosis, their non-affected first-degree relatives and non-related healthy controls. Metabolomic analysis was combined with neurocognitive assessment to identify multilevel endophenotypic patterns: one concerned reaction times during the performance of cognitive and emotional tests that have previously been associated with the glutamate neurotransmission system, the other involved metabolites involved directly and indirectly in the co-activation of the N-methyl-D-aspartate receptor, a major receptor of the glutamate system. These cognitive and metabolic endophenotypes may comprise a single construct, such that genetically mediated dysfunction in the glutamate system may be responsible for delays in response to cognitive and emotional functions in psychotic disorders. This focus on glutamatergic neurotransmission should guide drug discovery and experimental medicine programmes in schizophrenia and related disorders.This study was funded by the Mason Medical Research Trust, the Stanley Medical Research Institute, the GlaxoSmithKlein and the Pinsent Darwin funding.This is the final published version. It first appeared at http://www.nature.com/tp/journal/v5/n3/full/tp201526a.html
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