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Il pensiero politico di George Savile, primo marchese di Halifax (1633-1695). Monarchia limitata e conservazione politica in Inghilterra nella seconda metà del XVII secolo.
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Variations on the Author
Full text link“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
Neutrons for medicine
No full textThere are a lot of definitions of cancer: in a few words one could say that it represents
a group of diseases characterized by the growth and uncontrolled diffusion
of abnormal cells. Considering the number of deaths at the world level in 2005
(50 millions), cancer is responsible of 7.6 millions (that is 13%) with an expected
increase to 11.4 millions in 2030. The innovations in the field of radiotherapy,
chemotherapy, surgery and their combined applications have allowed to maintain
these numbers under control.
Radiation therapy has been used for the treatment of cancer and other diseases
for approximately 100 years. As early as 1897, two years after the discovery by
Wilhelm Conrad Rontgen, it was concluded that X-rays could be used for therapeutic
as well as diagnostic purposes. But nearly 30 years were necessary to make
radiotherapy world wide diffused: in fact, X-rays moved into clinical therapeutic
routine only in the early 1920s.
Since the first uses of radiation to treat cancer, important changes have been made
in this field and several developments have been accomplished, both from the instrumental
(new types of linear accelerators to generate higher energy radiation
beams) and medical (different types of ionizing radiation and progress in treatment
planning) points of view.
On the other hand there is a series of tumours whose survival curve has not varied
in time both in absolute and incremental terms: extended tumours (such as the
ones of stomach, liver and lung), tumours localized near or in vital organs (such
as the glioblastoma multiforme (GBM) in the brain), radioresistant tumours (such
as melanoma). The research for new ways of treatment, together with the discovery
of neutrons in 1932 and the studies concerning their properties, inspired in
the American biophysicist G. L. Locher in 1936 the attempt to use neutron beams
in radiotherapy in the so-called NCT (Neutron Capture Therapy) first and BNCT
(Boron Neutron Capture Therapy) then. BNCT could (and the conditional is a
must) represent a hope for all the cases still lacking a survival improvement.
BNCT is a technique that in principle joins the localization capability of radiotherapy
and the specificity of chemotherapy, allowing a selective release of the
dose only to cancer cells, without damaging the surrounding healthy tissues. This
technique is based on the irradiation with thermal and epithermal neutrons of a
boronated compound (the so called carrier) selectively concentrated in tumor cells.
Following the capture of a neutron, the 10B isotope emits high LET particles (an
and a 7Li ion) that release their whole energy in the cell where the boron atom
was present at the moment of the irradiation.
The first BNCT experimental treatments were performed during the '50s. Since
then, BNCT has met ups and downs in its history because of a physical and a biological
reason: from the physical point of view, the features of the neutron beam
(a flux >5 X 108 n cm-2 s-1 with an energy <10 keV) identify nuclear reactors
as the only adequate sources; from the biological point of view, the carriers that
bring the 10B inside the cell are not selective but exploit the greater metabolism
of the cancer cells with respect to the healthy ones. BNCT has been performed
in nuclear reactors in the United States (MIT, WSU), in Japan (KURRI, JRR-4),
in Argentina (RA-6), in Europe (JRC - the Netherlands, Medical AB - Sweden,
FiR1 - Finland) for activities of Phase I (toxicity) and of Phase II (ef_cacy); no
center has started a Phase III protocol (BNCT tests randomized with respect to the
standard techniques). Possible patients for BNCT treatments have to submit the
request for the therapy to the International Ethic Committee who analyzes all the
other possibilities before agreeing to a non standard treatment, a fact which limits
the number of patients and thus the available statistics.
To understand completely the impact and the advantages of BNCT with respect to
other techniques, it is necessary to study the boron concentration, its sub-cellular
distribution, its fixation molecular sites, its transport and its exchange dynamics
in several biological samples, possibly in a user friendly environment, easily accessible
and with a low photon or particle background. In other words, one of the
main tasks for the BNCT development in terms of clinical treatments is the study
of the pharmacokinetics of the carrier. This requires the development of reliable
methods for monitoring the boron concentration in healthy and tumour cells. This
study has to proceed in parallel with the design of in-hospital radiation sources.
The project of a treatment plan involves the work of medical doctors, oncologists,
biology and chemistry experts, physicists; the work of such a pool of people is
not easy to organize outside the hospital in a complicated environment such as the
one of a nuclear reactor. Moreover, also the test of new carriers or the trials on
new organs have to be inserted in the schedule of a reactor increasing times and
costs.
This thesis locates itself in the field of BNCT facing both the problems that still
limit its becoming a standard therapy. The work has been performed both at a
nuclear reactor and in a hospital environment collaborating with some of the most
important groups in Italy involved with BNCT.
The first chapter focuses on what cancer is, how it develops and how it can be
cured summarizing the three main treatment modalities (surgery, chemotherapy
and radiotherapy) and analyzing the brain cancer as an example of an illness still
without hope. The last part of the chapter concerns the rationale of BNCT, whose
ingredients are described in detail in chapter 2, which focuses both on the boron
carrier and the neutron beam.
Chapter 3 summarizes the features of a nuclear reactor neutron beam for BNCT,
describing the instruments and the procedure to characterize such a beam. In
particular, the chapter focuses on the measurements performed on the epithermal
column of the TAPIRO reactor (ENEA, Casaccia, Italy) with thermoluminescent
detectors. The data taking and analysis procedure are described in detail in order
to give an idea of the pros and cons of such non real time detectors.
Chapter 4 moves in the opposite direction, considering the development of a hospital
based BNCT beam both from the industrial point of view (presenting as an
example the proton + Li target accelerator proposed by IBA) and the completely
different approach of the PhoNeS (ProtoNeutron Source) project, which exploits
a standard radiotherapy linac producing neutrons via the Giant Dipole Resonance.
The chapter describes in detail the PhoNeS prototype and the measurements to
characterize the beam, presenting real time and innovative systems that can be
used thanks to the pulsed nature of the linac beam which allows to work in a
background free environment. The last part of the chapter is dedicated to the
application of this beam to the study of the boron concentration in biological samples
(urine and blood) to obtain the kinetic curves (that is the boron concentration
as a function of the time from the administration) for patients undergoing BNCT
treatments. This same .imaging system. has been applied to the study of another
possible organ that could bene_t of BNCT, that is the lung
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe 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
A Heuristic Procedure to Solve an Evolutionary Vehicle Routing Problem with Time Windows
No full textThe paper deals with a hybrid clustering-genetic algorithm that is applied to a rolling-horizon procedure for solving the dynamic vehicle routing problem with time windows. The paper mainly focuses on the advantages of introducing a clustering algorithm jointly with the genetic algorithm. Discussion is supported by numerical tests carried out by simulating the implementation of the procedure to the urban logistic centre of Padova, Italy. Results highlight that introducing clustering criteria to guide a genetic algorithm in the operations of generating the initial population, mutation and cross-over can improve the solution as 20%
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe 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
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