1,720,972 research outputs found
Quantitative Myocardial Magnetic Resonance Imaging
Get PDFQuantitative magnetic resonance imaging (MRI) is a robust and reproducible analysis method that has become the gold standard for cardiac analysis in clinical care. This thesis aims to optimize quantitative MRI characterization of myocardial tissue. A new method was introduced to obtain a synthetic image for drawing the left ventricle myocardial contours used for quantifying T2* for iron deposition detection, called the contrast-optimized composite image method, followed by a semi-automatic myocardial segmentation to ease segmentation difficulties in the bright blood multi-gradient echo image series. Two monoexponential T2* truncation methods were compared in quantifying iron loading at different iron content classifications. In T1 mapping, mean and median pixel value quantification were compared for their ability to detect heart function abnormality. Meanwhile, different perfusion models for quantifying myocardial blood flow (MBF) were equally sensitive to heart function. Higher reproducibility of T2* quantification was obtained by improving the TE image quality for myocardial segmentation and performing a semi-automatic myocardial segmentation. The two truncation methods showed similar T2* values at severe myocardial iron loading and diverged in lower myocardial iron content regions. Median quantification of pixel-wise measurement can replace the mean regardless of statistical data distribution, as shown in the early abnormality of heart function detected by native T1. Different MBF estimations are found between different perfusion models with the extended Toft and Fermi models allowing for better differentiation of the presence of significant stenosis. To conclude, this thesis has provided improved methods for characterizing myocardial tissue quantitatively
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
T2* assessment of the three coronary artery territories of the left ventricular wall by different monoexponential truncation methods
Get PDFOBJECTIVES: This study aimed at evaluating left ventricular myocardial pixel-wise T2* using two truncation methods for different iron deposition T2* ranges and comparison of segmental T2* in different coronary artery territories.MATERIAL AND METHODS: Bright blood multi-gradient echo data of 30 patients were quantified by pixel-wise monoexponential T2* fitting with its R2 and SNR truncation. T2* was analyzed at different iron classifications. At low iron classification, T2* values were also analyzed by coronary artery territories.RESULTS: The right coronary artery has a significantly higher T2* value than the other coronary artery territories. No significant difference was found in classifying severe iron by the two truncation methods in any myocardial region, whereas in moderate iron, it is only apparent at septal segments. The R2 truncation produces a significantly higher T2* value than the SNR method when low iron is indicated.CONCLUSION: Clear T2* differentiation between the three coronary territories by the two truncation methods is demonstrated. The two truncation methods can be used interchangeably in classifying severe and moderate iron deposition at the recommended septal region. However, in patients with low iron indication, different results by the two truncation methods can mislead the investigation of early iron level progression.</p
Development of PVA/Ag and PVA/NBT/Ag-Based Dosimeter Films with Optimized Concentration for Radiation Detection
Get PDFThis study aims to develop Polyvinyl Alcohol (PVA)-based dosimeter films with the addition of silver (Ag) and Nitroblue Tetrazolium (NBT) to enhance radiation detection. Two types of films were tested: PVA/Ag (0.75%) and PVA/NBT/Ag (0.75%). The film fabrication process involved dissolution, drying at room temperature, and cutting for testing with X-rays at varying voltages. Characterization was performed using UV-Vis spectra analysis and optical density measurements. The results showed that the PVA/NBT/Ag film exhibited higher absorbance compared to PVA/Ag, both before and after radiation exposure. A significant increase in optical density demonstrated a higher sensitivity for PVA/NBT/Ag, with an R2 value of 0.9571, indicating better linearity compared to PVA/Ag (R2 = 0.8821). Based on these findings, the PVA/NBT/Ag film is more effective in detecting radiation doses, making it a promising candidate for X-ray dosimetry
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Peningkatan Kualitas dan Kuantitas Produksi Jagung (Zea mays) Melalui Penyusupan N+ Menggunakan Sistem Pembangkit Plasma Lucutan Pijar Korona
Get PDFTanaman jagung merupakan komoditas pertanian yang penting khususnya bagi masyarakat Indonesia. Jagung dijadikan makanan pokok karena mengandung karbohidrat, protein, dan vitamin yang tinggi. Dalam perkembangannya, tanaman jagung Walt banyak diteliti teruatama mengenai pemuliaan untuk mendapatkan bibit unggul. Namun dalam segi penanamannya, bibit ungul yang dihasilkan masih tergantung pada penggunaan pupuk yang sebagian besar berasal dari pupuk Satan yang jumlahnya tidak sedikit. Hal ini tentu saga tidak menguntungkan bagi petani jagung.
Pada proses awal penanaman jagung, perkecambaban biji jagung merupakan proses yang sangat penting. Biji jagung dalam proses perkecambahannya memerlukan banyak unsur nitrogen yang pada umumnya diperoleh dari pupuk atau zat pemercepat perkecambahan. Penelitian ini bertujuan untuk mengetahui pengaruh radiasi plasma lucutan pijar korona terhadap perkecambahan biji jagung (Zea mays). Dalam penelitian ini unsur nitrogen diberikan pada biji jagung berupa ion I44. yang dihasilkan oleh plasma lucutan pijar korona. Unsur IsTE disusupkan sebelum biji dikecambahkan.
Penelitian dilakukan dengan metode eksperimental yang dilaksanakan pada bulan Mei hingga Oktober 2005 bertempat di Laboratorium Atom dan Nuklir Jurusan Fisika Fakultas Matematika dan Ilmu Pengetahuan Alam Universitas Diponegoro.
Plasma lucutan pijar korona dihasilkan oleh reaktor plasma berkonfigurasi geometri elektroda titik-bidang yang dibangkitkan oleh sumber tegangan tinggi DC 7,94 kV. Biji jagung diradiasi dengan plasma lucutan pijar
korona selama variasi waktu 10 hingga 60 menit. Setiap variasi waktu memerlukan sampel sebanyak 10 biji jagung dan perlakuan kontrolnya merupakan perlakuan tanpa radiasi plasma. Pengamatan terhadap perkecambahan dilakukan selama sate minggu.
Hasil pengamatan yang diperoleh menunjukkan bahwa perkecambahan biji jagung yang diradiasi plasma lebih cepat dibandingkan dengan biji jagung yang tidak diradiasi plasma. Hasil yang paling signifikan diberikan oleh sampel biji jagung yang diradiasi plasma selama 30 menit. Penyusupan NE pada biji jagung, selain dapat digunakan sebagai pengganti pupuk juga dapat digunakan sebagai bahan pemercepat perkecambahan. Dengan terpenuhinya kebutuhan nitrogen yang cukup maka perkecambahan biji jagung dapat terjadi lebih cepat sehingga akan mempersingkat pula waktu tumbuh tanaman jagung.
Corn is a signcant commodity especially for Indonesian people. Corn usedfOr primary food because contain of carbohydrate, protein, and high vitamin. In progress, corn research have been done to get high quality seed. In plant system, high quality seed that produced depend on fertilizer that mostly came from the synthetic fertilizer in large amount. Of course, it is not give benefit for the farmer.
In the initial process of corn planting, the corn seeding is the most important process. In this corn seeding need many of nitrogen from the fertilizer or from the seeding acceleration hormone. The goal of this research is to see the radiation effect of corona glow discharge plasma in corn seeding. The nitrogen gave to the corn seed in it ion that produce from the corona glow discharge plasma.
The research have been done with the experimental method in May until October 2005 in the Nuclear and Atom Laboratory, Physics Department, Mathematic and Nature Science Faculty of Diponegoro University.
The corona glow discharge plasma produced from plasma reactor with the point-to-plane electrodes configuration that generated by DC 7,94 kV Plasma that radiated to corn seed hit into the seed from 10 until 60 minutes. Every time of variation need 10 samples of corn seed and the control treatment is a treatment without plasma radiation. The observation of seeding have been done in one week.
From this research, show that the seeding of corn with plasma radiation is faster than the seeding of corn without plasma radiation. Plasma radiation give the optimum effect if radiation give in 30 minutes. The N+ radiation in corn that used for the substitute of fertilizer also used for seeding acceleration element. With the enough of nitrogen consumption, the corn seeding more faster and shorten the growth time of corn
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
- …
