305,282 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe 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
Intimal plus medial thickness of the arterial wall: a direct measurement with ultrasound imaging
No full textA study in vitro of specimens of human aortic and common carotid arteries was carried out to determine the feasibility of direct measurement (i.e., not from residual lumen) of arterial wall thickness with B mode real-time imaging. Measurements in vivo by the same technique were also obtained from common carotid arteries of 10 young normal male subjects. Aortic samples were classified as class A (relatively normal) or class B (with one or more atherosclerotic plaques). In all class A and 85% of class B arterial samples a characteristic B mode image composed of two parallel echogenic lines separated by a hypoechoic space was found. The distance between the two lines (B mode image of intimal + medial thickness) was measured and correlated with the thickness of different combinations of tunicae evaluated by gross and microscopic examination. On the basis of these findings and the results of dissection experiments on the intima and adventitia we concluded that results of B mode imaging of intimal + medial thickness did not differ significantly from the intimal + medial thickness measured on pathologic examination. With respect to the accuracy of measurements obtained by B mode imaging as compared with pathologic findings, we found an error of less than 20% for measurements in 77% of normal and pathologic aortic walls. In addition, no significant difference was found between B mode-determined intimal + medial thickness in the common carotid arteries evaluated in vitro and that determined by this method in vivo in young subjects, indicating that B mode imaging represents a useful approach for the measurement of intimal + medial thickness of human arteries in vivo
Calculation of nuclear particles production at high-energy photon beams from a Linac operating at 6,10 and 15 MV
No full textProduction of photonuclear particles in a tissue-equivalent medium has been calculated for linacs at 6, 10 and 15MV from
Varian TrueBeam. Based on the knowledge of bremsstrahlung fluence spectra and linac photon beam parameters, numerical
integration was performed on the cross sections for photoparticle production of the constituent elements of tissue
(2H,12C,13C,16O,17O,18O,14N,15N). At 15 MV, at the depth of photon maximum dose, the total absorbed dose due to neutrons,
protons, alphas and residual nuclei from photon reactions in tissue (5.5E−05 Gy per Gy of photons) is comparable to
that due to neutrons from accelerator head. Results reasonably agree with data reported in the literature using Monte Carlo
models simulating linac head components. This work suggests a simple method to estimate the dose contributed by the
photon-induced nuclear particles for high-energy photon beams produced by linacs in use, as it might be relevant for late
stochastic effects
Monte Carlo simulation of light fluence in tissue in a cylindrical diffusing fibre geometry
No full textDispelling the Myths Behind First-author Citation Counts
No full textWe 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
Author, publisher and bookseller : a tripartite synergy in Nigerian book industry
No full textThis work is about the roles of Author, Publisher and Bookseller in Book development in
Nigeria. The paper started by delving into the history of Book Publishing in Nigeria after
which it proceeded by defining who an author, a publisher, and a bookseller is and
expatiated on the indispensable roles of these key actors in Nigerian Book Industry and in
the emerging Information Society. Furthermore, the various constraints to book
development were identified while the paper advised on how the Book Industry can be
further promoted in Nigeria. However, the paper concluded and made recommendations
on how the Book sector can help in enhancing scholarship in the country
Studio degli effetti dell’uso combinato di fasci terapeutici di particelle cariche e radiosensibilizzanti in cellule tumorali umane coltivate in vitro
No full textNell’ambito delle terapie oncologiche è crescente l’interesse per trattamenti che abbinino alle radiazioni l’utilizzo di agenti chimici potenziali radiosensibilizzanti. L’obiettivo di questo tipo di trattamenti è quello di ottenere un miglior controllo locale del tumore e di ridurre la probabilità di formazione di metastasi.
In letteratura sono stati pubblicati numerosi studi sull’uso concomitante di fasci terapeutici di fotoni e diversi agenti chimici, ma attualmente ben pochi dati sono disponibili sull’azione combinata di adroni e agenti chimici radiosensibilizzanti.
In questo lavoro si descrivono i risultati di uno studio radiobiologico condotto su fasci terapeutici di fotoni e di protoni, ed alcuni dati preliminari relativi a fasci di ioni Carbonio, utilizzando cellule umane tumorali coltivate in vitro, trattate o meno, durante le 24 ore precedenti l’irraggiamento, con il chemioterapico Epothilone B, un agente microtubulo-stabilizzante.
I principali obiettivi dello studio sono:
- determinare l’efficacia dei fasci di adroni rispetto ai fotoni, per le linee cellulari studiate ( RBE)
- studiare la modalità di interazione delle diverse radiazioni con Epothilone B per valutare se sia additiva o sinergica.
Sono stati utilizzati i fasci terapeutici di adroni di CNAO (Pavia) e di fotoni presso l’Istituto Tumori di Milano. Lo studio è stato condotto su linee cellulari umane di glioblastoma multiforme (U251MG), adenocarcinoma polmonare a cellule non piccole (A549) e medulloblastoma pediatrico (DAOY). I principali effetti biologici studiati sono il mantenimento della capacità proliferativa (sopravvivenza clonogenica), la crescita e l’invasività cellulare.
I risultati ottenuti hanno mostrato che:
- l’RBE dei protoni dipende fortemente dalla linea cellulare e, per glioblastoma multiforme e per adenocarcinoma polmonare, è risultata maggiore di 1.1, valore attualmente usato nella pratica clinica.
- Il chemioterapico Epothilone B aumenta la citotossicità dei fasci di protoni e di fotoni e l’effetto del trattamento combinato è più che additivo
Sostanze Grasse Animali e Vegetali: Aspetti Qualitativi dei Prodotti Biologici
No full textThe aim of this study was to compare the effects of traditional and organic agricultural, feeding and breeding systems on the quality of lipids from animal and vegetable origin. The study was divided into three main sections: 1) evaluation of extra virgin olive oils obtained from olives produced by conventional and organic agricultural systems; 2) evaluation of liposoluble minor components obtained from soybeans and barley seeds produced by conventional and organic agricultural systems; 3) effects of different breeding and feeding systems on cholesterol oxidation and sterol content of freeze-dried egg yolks.
In general, slight, no significant differences were found between lipids from animal and vegetable products obtained by conventional and organic systems. Nevertheless, these results correspond to only one set of experiments, which could have been influenced by the particular weather conditions of the 2003 harvest. Therefore, this set of data should be considered as preliminary, but they represent a good starting basis for further studies in this field. More research is required in this area and it would be advisable to evaluate vegetable products from different harvest years, in order to draw valid conclusions
[Report to Chief J. E. Curry, by an unknown author #2]
No full textReport to Chief J. E. Curry, by an unknown author. The report contains a list of officers who gave depositions to the United States Attorney
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