1,720,999 research outputs found
Shock absorption performance of a motorbike helmet with honeycomb reinforced liner
No full textThe enhancement of the energy absorption properties of motorbike helmets could significantly improve the safety of riders. This study reports a novel concept of helmet design, which consists in the use of aluminium honeycomb as reinforcement material of the helmet liner. A modified version of a commercial helmet is presented, in which aluminium honeycombs are used in the energy absorbing liner. The ECE 22.05 standard tests were performed on both the prototype helmets and their commercial counterparts (presenting same dimensions, geometry, material properties and weight), and the dynamic responses were compared. The results showed that the prototype helmets provided better protection to the head from impacts against the kerbstone anvil. More limited improvements were also observed in some of the impacts on flat anvil, although other results indicated to some extent the limitations of the strategy adopted in our research
Sonoisterografia : valutazione della cavità uterina e dello stato tubarico
No full textL’ecoisterosalpingografia (EISG) è una tecnica che consente di studiare la cavità uterina e lo stato tubarico. Tale procedura diagnostica consiste nell’iniettare una soluzione salina (NaCL 0,9%) nella cavità uterina sotto controllo ecografico continuo.
Scopo del nostro studio è di valutare l’efficacia della EISG nella diagnosi della patologia uterina e della pervietà tubarica e di confrontantare i risultati con quelli ottenuti con l’isteroscopia diagnostica e l’ecografia transvaginale.
Abbiamo studiato 221 pazienti infertili, con età compresa tra i 23-44 (media 33.5). Tutte le pazienti sono state sottoposte ad ecografia transvaginale seguita da isteroscopia diagnostica e EISG. Delle 221 pazienti, 155 presentavano anomalie della cavità uterina rilevate all’esame isteroscopico. L’ecografia ha permesso di individuare 105 delle 155 patologie uterine (67.0%). Ad eccezione per un singolo polipo endometriale, la sonoisterografia ha permesso di evidenziare tutte le anomalie (99.3%). Abbiamo inoltre effettuato un isterosalpingografia (ISG) dopo sei mesi circa di intervallo in 53 donne per valutare l’effficacia diagnostica dell’EISG nello studio della pervietà tubarica. Le tube sono risultate pervie in 39 (73.3%) e 41 (77%) casi rispettivamente dopo EISG e ISG. Percio’, i risultati ottenuti con l’EISG risultano essere efficaci se confrontati con quelli ottenuti con gli altri mezzi diagnostici. Tutte le 155 donne hanno ben tollerato l’esame che si effettua in 15 minuti circa (SD 5.6 min) permettendo di ottenere immagini di ottimo livello e qualità. Inoltre l’ EISG permette un precisa programmazione della chirurgia endoscopica e di ottenere un preciso screening delle anomalie dell’endometrio e del miometrio. In casi di mioma sottomucoso da trattare con isteroscopia, ci permette di misurare esattamente lo spessore del miometrio e di formulare una diagnosi immediata perché effettuabile anche nei casi di sanguinamenti uterini. Quindi la EISG è un metodica diagnostica di rapida attuazione, facile da eseguire e non invasiva e consente un risparmio in termini economici. E’ percio’ raccomandabile per la diagnosi di anomalie della cavità uterina e dello stato tubarico
Fertility preservation in female cancer patients: an emerging challenge for physicians
No full textFertility preservation has become an issue of great importance in female cancer patients due
to increasing survival rates and delayed childbearing. It is an emerging challenge for
physicians, cause of several related issues (multidisciplinary approach, doctor-patient
communication, ethical, religious and legal problems) and many unresolved questions.
This review aims to update the latest literature data, summarizing the effects of cancer
treatments on female fertility and the various options currently available to offer cancer
patients the opportunity of future pregnancies.
Many strategies exist for fertility preservation in young women and they should be assessed
according to the patient’s age, type of cancer, partner status and time available. Some
techniques are well established, others are still experimental. The established methods include
embryo cryopreservation, transposition of ovaries prior to radiation therapy, radiation
shielding of gonads and conservative surgical approaches. The experimental methods include
oocyte cryopreservation, in vitro maturation of oocytes, ovarian tissue cryopreservation and
transplantation, and ovarian suppression. Improvement of these techniques as well as better
characterization of their success rates and risks, await further investigation. Oocytes donation
and gestational surrogacy represent the last options.
Thus, the care of these patients is challenging, complex and requires a multidisciplinary
approach. A close collaboration between Oncologists, Specialists in Reproductive Medicine,
Gynecologic Oncologists and Endocrinologists is crucial for always offering the best possible
option
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
Static and dynamic energy absorption of aluminium honeycombs and polymeric foams composites
No full textThe use of innovative materials as energy absorbers for motorbike helmets might
have a significant impact in the safety of motorbike riders, currently among the most
vulnerable road users.
In this regard, the effect of the interaction between aluminium honeycombs and
polymeric foams in the design of innovative liners is investigated by studying their
behaviour under compressive loading conditions.
Quasi-static and impact compressive loadings were applied to samples of twolayered
structures made of aluminium honeycombs and expanded polystyrene foams,
in order to observe their deformation modes, determine their energy absorption
properties and the influence of the loading speed in their mechanical response. The
same tests were performed on the expanded polystyrene foams and on the honeycomb
layers separately. The results were compared and it was shown that although
aluminium honeycombs alone offer the highest energy absorption levels, their
coupling with EPS foams is preferred for the protection of the head
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
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
- …
