484 research outputs found

    Assessment of dimensions of pneumatisation of the anterior clinoid process in middle Anatolian population by computed tomography

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    Background: The anterior clinoid process (ACP) is usually removed during surgical procedures of the cellar region. The ACP may be different length and width in people; it may be also pneumatic. Therefore, we aimed to determine dimensions and rates of pneumatisation of the ACP in the large study group with clinicallyimportance.Materials and methods: One thousand and thirty-one (592 female, 439 male) cranial computed tomography (CT) of the middle Anatolian population was used in this study. The length and basal width of the ACP were measured on the cranial CT. Also; incidence and degree of ACP pneumatisation were identified.Results: The width of the right and left ACPs in females were 10.80 Ā± 2.27 mm and 10.53 Ā± 2.07 mm, respectively. The width of the right and left ACPs in males were 11.08 Ā± 2.39 mm and 10.98 Ā± 2.35 mm, respectively. The length of the right and left ACPs in females were 8.32 Ā± 2.40 mm and 8.34 Ā± 2.35 mm, respectively. The length of the right and left ACPs in males were 8.87 Ā± 2.62 mm and 8.93 Ā± 2.64 mm, respectively. There was statistically significant difference between males and females in ACP dimensions, except for the width of the right ACP. Pneumatisation of the ACP was observed on the right side in 46 (9.3%) cases,on the left side in 53 (10.6%) cases, and bilaterally in 32 (6.5%) cases. Incidence of pneumatisation of the ACP was decreased in the age group of 1 month to 20 years. While the incidence of bilateral pneumatisation of the ACP was higher in individuals aged 21ā€“40.Conclusions: Radiologically recognising pneumatisation and anatomical variations of the ACP may be helpful in decreasing the incidence of surgical complications during anterior clinoidectomy

    Fractal-like Distributions over the Rational Numbers in High-throughput Biological and Clinical Data

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    Recent developments in extracting and processing biological and clinical data are allowing quantitative approaches to studying living systems. High-throughput sequencing, expression profiles, proteomics, and electronic health records are some examples of such technologies. Extracting meaningful information from those technologies requires careful analysis of the large volumes of data they produce. In this note, we present a set of distributions that commonly appear in the analysis of such data. These distributions present some interesting features: they are discontinuous in the rational numbers, but continuous in the irrational numbers, and possess a certain self-similar (fractal-like) structure. The first set of examples which we present here are drawn from a high-throughput sequencing experiment. Here, the self-similar distributions appear as part of the evaluation of the error rate of the sequencing technology and the identification of tumorogenic genomic alterations. The other examples are obtained from risk factor evaluation and analysis of relative disease prevalence and co-mordbidity as these appear in electronic clinical data. The distributions are also relevant to identification of subclonal populations in tumors and the study of the evolution of infectious diseases, and more precisely the study of quasi-species and intrahost diversity of viral populations

    Effects of Electron Correlations on Hofstadter Spectrum

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    By allowing interactions between electrons, a new Harper's equation is derived to examine the effects of electron correlations on the Hofstadter energy spectra. It is shown that the structure of the Hofstadter butterfly ofr the system of correlated electrons is modified only in the band gaps and the band widths, but not in the characteristics of self-similarity and the Cantor set.Comment: 13 pages, 5 Postscript figure

    Phase Separation Based on U(1) Slave-boson Functional Integral Approach to the t-J Model

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    We investigate the phase diagram of phase separation for the hole-doped two dimensional system of antiferromagnetically correlated electrons based on the U(1) slave-boson functional integral approach to the t-J model. We show that the phase separation occurs for all values of J/t, that is, whether 0<J/t<10 < J/t < 1 or J/tā‰„1J/t \geq 1 with J, the Heisenberg coupling constant and t, the hopping strength. This is consistent with other numerical studies of hole-doped two dimensional antiferromagnets. The phase separation in the physically interesting J region, 0<J/tā‰²0.40 < J/t \lesssim 0.4 is examined by introducing hole-hole (holon-holon) repulsive interaction. We find from this study that with high repulsive interaction between holes the phase separation boundary tends to remain robust in this low JJ region, while in the high J region, J/t > 0.4, the phase separation boundary tends to disappear.Comment: 4 pages, 2 figures, submitted to Phys. Rev.

    Conformity and tradition are more important than environmental values in constraining resource overharvest

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    We present the results of a hybrid research design that borrows from both experimental techniques-experimental games-and observational techniques-surveys-to examine the relationships between basic human values and exposure to natural ecosystems, on the one hand, and collective action for resource governance, on the other. We initially hypothesize that more frequent exposure to forests, and more pro-environmental values will be associated with more conservation action. However, we find that other values-tradition and conformity-are more important than pro-environmental values or exposure to nature. Our results imply that resource governance is likely to be more successful where resource users hold values that facilitate cooperation, not necessarily strong pro-environmental values

    On the Origin of Peak-dip-hump Structure in the In-plane Optical Conductivity of the High TCT_C Cuprates; Role of Antiferromagnetic Spin Fluctuations of Short Range Order

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    An improved U(1) slave-boson approach is applied to study the optical conductivity of the two dimensional systems of antiferromagnetically correlated electrons over a wide range of hole doping and temperature. Interplay between the spin and charge degrees of freedom is discussed to explain the origin of the peak-dip-hump structure in the in-plane conductivity of high TCT_C cuprates. The role of spin fluctuations of short range order(spin singlet pair) is investigated. It is shown that the spin fluctuations of the short range order can cause the mid-infrared hump, by exhibiting a linear increase of the hump frequency with the antiferromagnetic Heisenberg coupling strength
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