717 research outputs found

    Entropy measures for complex networks: Toward an information theory of complex topologies

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    The quantification of the complexity of networks is, today, a fundamental problem in the physics of complex systems. A possible roadmap to solve the problem is via extending key concepts of information theory to networks. In this paper we propose how to define the Shannon entropy of a network ensemble and how it relates to the Gibbs and von Neumann entropies of network ensembles. The quantities we introduce here will play a crucial role for the formulation of null models of networks through maximum-entropy arguments and will contribute to inference problems emerging in the field of complex networks.Comment: (4 pages, 1 figure

    Ab Initio Spatial Phase Retrieval via Fluorescence Intensity Triple Correlations

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    A complete method for ab initio phase retrieval via spatial intensity triple correlations is described. Simulations demonstrate accurate phase retrieval for clusters of classical incoherent emitters

    A study on greater trochanter reconstruction in unstable inter trochanteric fracture of femur

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    Background: A study on greater trochanter reconstruction in unstable intertrochanteric femur fracture. Methods: The 2019 to 2022, Patients were randomly divided into two groups with the help of computer-generated coded envelopes; Group A (unstable intertrochanteric femur fracture patients treated by hemi-arthroplasty or PFN with greater trochanter reconstruction) and Group B (unstable intertrochanteric femur fracture Patients Treated by hemi-arthroplasty or PFN with no greater trochanter reconstruction) with 20 patients in each group Outcomes were evaluated based on Harris hip score calculated at 2 weeks 6 weeks 3 months and 6 months. Results: Most common surgery in study groups performed were PFN, on radiology as non-union and union, most common study participants show union, on follow up at 2,6 weeks,3 months and 6 months Harris hip score was calculated and it was found to be statistically significant suggestive of improved quality of life, on radiological evaluation all cases shows non-displacement of GT position but in follow-ups at 6 weeks, 3 months and 6 months one case each reported displaced implant. Conclusions: The result of our study shows that there is improved quality of life and significant improvement in Harris hip score after reconstruction of greater trochanter in unstable intertrochanteric femur fracture

    Anatomical variations in the branches of the human aortic arch: a recent study of a South Australian population

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    Variations of the branches of the aortic arch are likely to occur as a result of the altered development of certain branchial arch arteries during the embryonic period of gestation. In the present investigation the pattern of branches of the aortic arch was studied in 81 cadavers from a recent South Australian population of European descent, who have migrated to (n = 38) or were born and lived in (n = 43) South Australia during the twentieth century. Two principal variations were noted in the present study. Firstly, in 6 cadavers, the left vertebral artery originated directly from the arch of the aorta, between the left common carotid and the left subclavian arteries. The 6 subjects were among the subgroup born in South Australia, giving an incidence of 13.95%, which is much higher than in previous reports. The overall incidence of 7.41%, when related to the whole group, is also higher than incidences reported in other populations. The presence of this variation suggests that in some individuals part of the aortic arch is formed from the left 7th inter-segmental artery. Secondly, none of the cadavers examined had the thyroidea ima artery, contrasting with previously reported incidences that varied between 4% and 10%. Since all 6 cadavers with the left vertebral artery variant were born in South Australia, it is suggested that environmental factors may have contributed to this variation. Significant environmental changes in South Australia around the turn of the twentieth century are discussed. This study represents the first systematic investigation of the branches of the aortic arch in a South Australian population and provides data relevant to the practice of medicine

    Detection of Dense Molecular Gas in Inter-Arm Spurs in M51

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    Spiral arm spurs are prominent features that have been observed in extinction and 8μ\mum emission in nearby galaxies. In order to understand their molecular gas properties, we used the Owens Valley Radio Observatory to map the CO(J=1--0) emission in three spurs emanating from the inner northwestern spiral arm of M51. We report CO detections from all three spurs. The molecular gas mass and surface density are MH2∼3×106_{H2} \sim3\times10^6 M_{\sun} and ΣH2∼\Sigma_{H2} \sim50 M_{\sun} pc−2^{-2}. Thus, relative to the spiral arms, the spurs are extremely weak features. However, since the spurs are extended perpendicular to the spiral arms for ∼\sim500 pc and contain adequate fuel for star formation, they may be the birthplace for observed inter-arm HII regions. This reduces the requirement for the significant time delay that would be otherwise needed if the inter-arm star formation was initiated in the spiral arms. Larger maps of galaxies at similar depth are required to further understand the formation and evolution of these spurs and their role in star formation - such data should be forthcoming with the new CARMA and future ALMA telescopes and can be compared to several recent numerical simulations that have been examining the evolution of spiral arm spurs.Comment: 6 pages, 3 figures, emulate-apj format, accepted in Ap

    Tibial tuberosity fracture in adult as an unusual pattern of injury

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    Tibial tuberosity avulsion is an uncommon fracture in adults, such lesions typically seen in adolescent male with well-developed quadriceps, ligaments when they are stronger than growth plate. We described a case of 51-year-old gentlemen had direct trauma to left knee, no risk factors were identified, not able to walk, difficulty in straight leg raise test, radiograph of left knee showed tibial tuberosity avulsion fracture. The fracture was treated with open reduction and internal fixation, f/u with successful rehabilitation which results in good range of motion and excellent function at knee joint. The aim of study is present unusual and rare case of tibial tuberosity Avulsion fracture in adult, early diagnosis, surgical mode of treatment, post-surgery rehabilitation and possible complications

    Interaction of two memory enhancing herbal drugs Memory Plus and Mentat with diazepam and phenytoin sodium in mice

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    Background: The non-medical self-administration of memory enhancing drugs is a common practice. Present study was designed to evaluate interactions of two such herbal drugs Memory Plus (MP) and Mentat, with other central nervous system (CNS) active drugs.Methods: Two activities - pentobarbitone sleeping time (PST) and maximal electroshock seizures (MES) were performed using adult albino mice weighing 25-30 g to observe the interactions of the herbal drugs with diazepam and phenytoin sodium, respectively. For each activity, animals were divided into seven groups of six mice each. Group I was a control group receiving 0.2 ml of 1% Tween 80 i.p/0.2 ml saline p.o, Group II, III and IV acute treatment groups; received single dose of herbal (2 mg/kg i.p MP or 200 mg/kg p.o Mentat) CNS-active drugs alone in subeffective doses group II - diazepam 5 mg/kg i.p, Group III PS 15 mg/kg i.p and Group IV - MP/Mentat+diazepam or PS, respectively. Groups V, VI, and VII were subchronic treatment groups, received drugs once daily for 8 days same as acute treatment groups. Sleeping time was measured as the interval between the loss and recovery of righting reflex and anticonvulsant activity by giving supra maximal shock via ear electrodes using a techno electro convulsiometer.Results: Both MP and Mentat showed potentiation of effect of diazepam and PS in subchronic treatment groups by significantly prolonging PST (p<0.05) and by showing significant percentage protection in MES method (p<0.05) compared to control group.Conclusion: Subchronic administration of MP and Mentat shows significant interaction with diazepam and PS. Further human studies are warranted to confirm these findings

    Comparative Analysis of Molecular Clouds in M31, M33 and the Milky Way

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    We present BIMA observations of a 2\arcmin field in the northeastern spiral arm of M31. In this region we find six giant molecular clouds that have a mean diameter of 57±\pm13 pc, a mean velocity width of 6.5±\pm1.2 \kms, and a mean molecular mass of 3.0 ±\pm 1.6 ×\times 105^5\Msun. The peak brightness temperature of these clouds ranges from 1.6--4.2 K. We compare these clouds to clouds in M33 observed by \citet{wilson90} using the OVRO millimeter array, and some cloud complexes in the Milky Way observed by \cite{dame01} using the CfA 1.2m telescope. In order to properly compare the single dish data to the spatially filtered interferometric data, we project several well-known Milky Way complexes to the distance of Andromeda and simulate their observation with the BIMA interferometer. We compare the simulated Milky Way clouds with the M31 and M33 data using the same cloud identification and analysis technique and find no significant differences in the cloud properties in all three galaxies. Thus we conclude that previous claims of differences in the molecular cloud properties between these galaxies may have been due to differences in the choice of cloud identification techniques. With the upcoming CARMA array, individual molecular clouds may be studied in a variety of nearby galaxies. With ALMA, comprehensive GMC studies will be feasible at least as far as the Virgo cluster. With these data, comparative studies of molecular clouds across galactic disks of all types and between different galaxy disks will be possible. Our results emphasize that interferometric observations combined with the use of a consistent cloud identification and analysis technique will be essential for such forthcoming studies that will compare GMCs in the Local Group galaxies to galaxies in the Virgo cluster.Comment: Accepted for Publication in the Astrophysical Journa
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