1,682 research outputs found
Historical and Epistemological Reflections on the Culture of Machines around the Renaissance: Machines, Machinaries and Perpetual Motion. Seconda parte
This paper is the second part of our recent paper \u2018Historical
and Epistemological Reflections on the Culture of Machines around
the Renaissance: How Science and Technique Work\u2019 (Pisano & Bussotti
2014a). In the first paper\u2014which discussed some aspects of the relations
between science and technology from Antiquity to the Renaissance\u2014we
highlighted the differences between the Aristotelian/Euclidean tradition and
the Archimedean tradition. We also pointed out the way in which the two
traditions were perceived around the Renaissance. The Archimedean tradition
is connected with machines: its relationship with science and construction of
machines should be made clear. It is enough to think that Archimedes mainly
dealt with three machines: lever, pulley and screw (and a correlated principle of
mechanical advantage). As underlined in the first part, our thesis is that many
machines were constructed by people who ignored theory, even though, in
other cases, the knowledge of the Archimedean tradition was a precious help
in order to build machines. Hence, an a priori idea as to the relations between
the Archimedean tradition and construction of machines cannot exist. In this
second part we offer some examples of functioning machines constructed
by people who ignored any physical theory, whereas, in other cases, the ignorance of some principles\u2014such as the impossibility of a perpetuum
mobile\u2014induced the attempt to construct impossible machines. What is very
interesting is that these machines did not function, of course, as a perpetuum
mobile, but anyway had their functioning and were useful for certain aims,
although they were constructed on an idea which is completely wrong from
a theoretical point of view. We mainly focus on the Renaissance and early
modern period, but we also provide examples of machines built before and
after this period. We have followed a chronological order in both parts,
starting from the analysis of the situation in ancient Greece. Therefore, in the
first part, we have examined the relations between the Aristotelian/Euclidean
and Archimedean traditions from ancient Greece to the early modern age.
In this second part, we analyse the relations of Archimedean tradition/
construction of machines from ancient Greece to the 19th century, focusing
on the mentioned period. We remind the reader that our aim is to prove
an epistemological thesis, not to provide a complete historical endeavour
Introduction. 1564-2014. Homage to Galileo Galilei
1 The Iuvenilia–Early Galilean works When Galileo Galilei (1564-1642) published the Sidereus Nuncius in 1610 [Galilei 1890-1909, III, pt 1, 51-96], he was a famous enough scientist, who was not young: for, he was 46. Nevertheless, this little book represented the fundamental turning point in Galileo’s life and scientific production. The Sidereus Nuncius was very successful and gave rise to numerous discussions. Some scholars defended Galileo—the most important was Kepler—, many others, with a..
« La théorie analytique de la chaleur » : Notes on Fourier et Lamé
Abstract Since the second half of 18th century, new instruments produced many data and improvements (not only in mechanics) of the scientific knowledge and its applications. Thanks to Euler and Lagrange, the differential equations started to become an important instrument to solve very complex problems, beforehand considered as unsolvable. The Traité de mécanique céleste (1805) by Laplace represents the climax of such an approach and soon becomes part of an important process of exaltation of ..
Fatty liver disease and hypertransaminasemia hiding the association of clinically silent Duchenne muscular dystrophy and hereditary fructose intolerance
We report a case with the association of well self-compensated hereditary fructose intolerance and still poorly symptomatic Duchenne type muscular dystrophy. This case illustrates the problems of a correct diagnosis in sub-clinical patients presenting with “cryptogenic” hypertransaminasemia
2020 WSES guidelines for the detection and management of bile duct injury during cholecystectomy.
Bile duct injury (BDI) is a dangerous complication of cholecystectomy, with significant postoperative sequelae for the patient in terms of morbidity, mortality, and long-term quality of life. BDIs have an estimated incidence of 0.4-1.5%, but considering the number of cholecystectomies performed worldwide, mostly by laparoscopy, surgeons must be prepared to manage this surgical challenge. Most BDIs are recognized either during the procedure or in the immediate postoperative period. However, some BDIs may be discovered later during the postoperative period, and this may translate to delayed or inappropriate treatments. Providing a specific diagnosis and a precise description of the BDI will expedite the decision-making process and increase the chance of treatment success. Subsequently, the choice and timing of the appropriate reconstructive strategy have a critical role in long-term prognosis. Currently, a wide spectrum of multidisciplinary interventions with different degrees of invasiveness is indicated for BDI management. These World Society of Emergency Surgery (WSES) guidelines have been produced following an exhaustive review of the current literature and an international expert panel discussion with the aim of providing evidence-based recommendations to facilitate and standardize the detection and management of BDIs during cholecystectomy. In particular, the 2020 WSES guidelines cover the following key aspects: (1) strategies to minimize the risk of BDI during cholecystectomy; (2) BDI rates in general surgery units and review of surgical practice; (3) how to classify, stage, and report BDI once detected; (4) how to manage an intraoperatively detected BDI; (5) indications for antibiotic treatment; (6) indications for clinical, biochemical, and imaging investigations for suspected BDI; and (7) how to manage a postoperatively detected BDI
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Research on Markets for Inventions and Implications for R&D Allocation Strategies
Several streams of literature have examined the phenomenon of “markets for inventions”, that is, the trade of elements of knowledge which are “disembodied” from individuals, organizations, and products. The aims of this paper are to bring together the various streams of research in this area and discuss their major assumptions and limitations, in order to provide a comprehensive framework for understanding the phenomenon, and identify promising paths for future research. We start our review by identifying the object of market exchange—that is, an invention whose knowledge has been codified and disembodied from individuals, organizations, or artifacts. We then identify those factors that enable firms to trade inventions, distinguishing between institutional-, firm-, and industry-level factors. We close our analysis of the extant literature by discussing the implications of markets for inventions for firm behavior and performance. Against this background, we highlight an important avenue for future research. A neglected implication of the development of invention markets is that firms are confronted with a wide variety of technological paths from which to choose, because the opportunity to acquire technologies on the market offers them a greater variety that can their internal R&D departments. However, the streams of research on markets for inventions and on R&D allocation strategies have been surprisingly disconnected so far. Hence, in the final section, we start to establish and explore the link between these literatures, and to identify a research agenda in this domain
Goodbye Hartmann trial: a prospective, international, multicenter, observational study on the current use of a surgical procedure developed a century ago
Background: Literature suggests colonic resection and primary anastomosis (RPA) instead of Hartmann's procedure (HP) for the treatment of left-sided colonic emergencies. We aim to evaluate the surgical options globally used to treat patients with acute left-sided colonic emergencies and the factors that leading to the choice of treatment, comparing HP and RPA. Methods: This is a prospective, international, multicenter, observational study registered on ClinicalTrials.gov. A total 1215 patients with left-sided colonic emergencies who required surgery were included from 204 centers during the period of March 1, 2020, to May 31, 2020. with a 1-year follow-up. Results: 564 patients (43.1%) were females. The mean age was 65.9 ± 15.6 years. HP was performed in 697 (57.3%) patients and RPA in 384 (31.6%) cases. Complicated acute diverticulitis was the most common cause of left-sided colonic emergencies (40.2%), followed by colorectal malignancy (36.6%). Severe complications (Clavien-Dindo ≥ 3b) were higher in the HP group (P < 0.001). 30-day mortality was higher in HP patients (13.7%), especially in case of bowel perforation and diffused peritonitis. 1-year follow-up showed no differences on ostomy reversal rate between HP and RPA. (P = 0.127). A backward likelihood logistic regression model showed that RPA was preferred in younger patients, having low ASA score (≤ 3), in case of large bowel obstruction, absence of colonic ischemia, longer time from admission to surgery, operating early at the day working hours, by a surgeon who performed more than 50 colorectal resections. Conclusions: After 100 years since the first Hartmann's procedure, HP remains the most common treatment for left-sided colorectal emergencies. Treatment's choice depends on patient characteristics, the time of surgery and the experience of the surgeon. RPA should be considered as the gold standard for surgery, with HP being an exception
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