46 research outputs found
Federigo Enriques at the 1935 International Congress for Scientific Philosophy in Paris
Au CongrĂšs de philosophie scientifique de 1935 comme lors du lancement de lâEncyclopĂ©die internationale de la science unifiĂ©e, Federigo Enriques Ă©tait reconnu par les nĂ©o-positivistes comme un de leurs pĂšres fondateurs, sans quâil fĂ»t tout Ă fait dâaccord. Ă Paris, Enriques reprĂ©sentait le groupe des philosophes des sciences italiens et son nom Ă©tait liĂ© au journal Scientia, ouvert aux contributions des positivistes logiques. Ces derniers, dĂ©sireux de constituer un front commun pour lutter contre les philosophies idĂ©alistes et mĂ©taphysiques alors dominantes, surestimaient sans doute la force du groupe italien, comme ils sous-estimaient les critiques dâEnriques sur lâusage de la logique formelle ou sur lâimportance du langage. DĂšs les dĂ©buts de son implication en philosophie, il avait soulignĂ© la nĂ©cessitĂ© dâune fondation psychologique des concepts scientifiques, et en 1901, il avait donnĂ© un exemple de ce type dâanalyse pour les postulats de la gĂ©omĂ©trie. Il nâapprĂ©ciait guĂšre les travaux logiques de Giuseppe Peano, affirmant que son formalisme manquait de bases psychologiques. Cependant, contre les mouvements anti-rationalistes de son temps, il dĂ©fendait la valeur cognitive de la science et, dans ce climat dâapprĂ©ciation mutuelle, les diffĂ©rences passaient au second plan.At the 1935 Congress for Scientific Philosophy, and at the launch of the International Encyclopedia of Unified Science, Federigo Enriques was recognized by the leaders of neo-positivism as one of their founding fathers, not to his complete agreement. In Paris, Enriques represented the Italian group of philosophers of science and his name was associated with the important journal Scientia, which was open to contributions by logical positivists. This latter movement, which wanted to create a front composed of the opponents of the prevailing idealistic and metaphysical philosophies, probably underestimated the criticism of Enriques with respect to formal logic and the importance of language. From the start of his involvement in philosophy in the first years of the twentieth century, Enriques had stressed the necessity of a psychological foundation for scientific concepts. He did not appreciate the logical work of Giuseppe Peano, claiming that his formalism didnât have the right psychological basis. However, he defended the cognitive value of science against the anti-rationalist movements of the time, and in the climate of mutual appreciation differences were nuanced down
A new minimally invasive technique for the repair of diastasis recti: a pilot study
BACKGROUND: Diastasis recti is an abdominal wall defect that occurs frequently in women during pregnancy. Patients with diastasis can experience lower back pain, uro-gynecological symptoms, and discomfort at the level of the defect. Diastasis recti is diagnosed when the inter-rectus distance is>2cm. Several techniques, including both minimally invasive and open access surgical treatment, are available. Abdominoplasty with plication of the anterior rectus sheath is the most commonly used, with the major limitation of requiring a wide skin incision. The new technique we propose is a modification of Costa's technique that combines Rives-Stoppa principles and minimally invasive access using a surgical stapler to plicate the posterior sheaths of the recti abdominis.METHODS: It is a fully laparoscopic technique. The pneumoperitoneum is induced from a sovrapubic trocar, placed using an open access technique. The posterior rectus sheath is dissected from the rectus muscle using a blunt dissector to create a virtual cavity. The posterior sheets of the recti muscles are plicated using an endo-stapler. A mesh is then placed in the retromuscular space on top of the posterior sheet without any fixation. Using a clinical questionnaire, we analyzed the outcomes in 74 patients who underwent minimally invasive repair for diastasis of the rectus abdominis sheath.RESULTS: Seventy-four patients (9 men and 65 women) were treated using this technique. Follow-up was started two months after surgery. All procedures were conducted successfully. There were no major complications or readmissions. No postoperative infections were reported. There were two recurrences after six months. There was a significant reduction in symptoms.CONCLUSIONS: This new method is feasible and has achieved promising results, even though a longer follow-up is needed to objectively assess this technique
Optical design and performance simulations for the 1.49 keV beamline of the BEaTriX X-ray facility
The BEaTriX (Beam Expander Testing X-ray) facility, now operational at INAF-Brera Astronomical Observatory, will represent a cornerstone in the acceptance roadmap of Silicon Pore Optics (SPO) mirror modules, and will so contribute to the final angular resolution of the ATHENA X-ray telescope. By expansion and collimation of a microfocus X-ray source via a paraboloidal mirror, a monochromation stage, and an asymmetric crystal, BEaTriX enables the full-aperture illumination of an SPO mirror module with a parallel, monochromatic, and broad (140 mm Ă 60 mm) X-ray beam. The beam then propagates in a 12 m vacuum range to image the point spread function of the mirror module, directly on a focal plane camera. Currently the 4.51 keV beamline, based on silicon crystals, is operational in BEaTriX. A second beamline at 1.49 keV, which requires a separate paraboloidal mirror and organic crystals (ADP) for beam expansion, is being realized. As for monochromators, the current design is based on asymmetric quartz crystals. In this paper, we show the current optical design of the 1.49 keV beamline and the optical simulations carried out to predict the achievable performances in terms of beam collimation, intensity, and uniformity. In the next future, the simulation activity will allow us to determine manufacturing and alignment tolerances for the optical components
First light of BEaTriX, the new testing facility for the modular X-ray optics of the ATHENA mission
Aims: The Beam Expander Testing X-ray facility (BEaTriX) is a unique X-ray apparatus now operated at the Istituto Nazionale di Astrofisica (INAF), Osservatorio Astronomico di Brera (OAB), in Merate, Italy. It has been specifically designed to measure the point spread function (PSF) and the effective area (EA) of the X-ray mirror modules (MMs) of the Advanced Telescope for High-ENergy Astrophysics (ATHENA), based on silicon pore optics (SPO) technology, for verification before integration into the mirror assembly. To this end, BEaTriX generates a broad, uniform, monochromatic, and collimated X-ray beam at 4.51 keV. The beam collimation is better than a few arcseconds, ensuring reliable tests of the ATHENA MMs, in their focus at a 12 m distance. Methods: In BEaTriX, a micro-focus X-ray source with a titanium anode is placed in the focus of a paraboloidal mirror, which generates a parallel beam. A crystal monochromator selects the 4.51 keV line, which is expanded to the final size by a crystal asymmetrically cut with respect to the crystalline planes. An in-house-built Hartmann plate was used to characterize the X-ray beam divergence, observing the deviation of X-ray beams from the nominal positions, on a 12-m-distant CCD camera. After characterization, the BEaTriX beam has the nominal dimensions of 170 mm Ă 60 mm, with a vertical divergence of 1.65 arcsec and a horizontal divergence varying between 2.7 and 3.45 arcsec, depending on the monochromator setting: either high collimation or high intensity. The flux per area unit varies from 10 to 50 photons/s/cm2 from one configuration to the other. Results: The BEaTriX beam performance was tested using an SPO MM, whose entrance pupil was fully illuminated by the expanded beam, and its focus was directly imaged onto the camera. The first light test returned a PSF and an EA in full agreement with expectations. As of today, the 4.51 keV beamline of BEaTriX is operational and can characterize modular X-ray optics, measuring their PSF and EA with a typical exposure of 30 min. Another beamline at 1.49 keV is under development and will be integrated into the current equipment. We expect BEaTriX to be a crucial facility for the functional test of modular X-ray optics, such as the SPO MMs for ATHENA
Peanoâs Reception in the USA. Wilsonâs Review of Russellâs Principles
In a review of Russellâs Principles from 1904, Edwin B. Wilson pays great attention to Peanoâs work and that of his collaborators. His purpose was to make this work known in the USA where it âunfortunately is very little known and still less appreciatedâ. Wilson expands Russellâs well-known acknowledgement of Peanoâs influence on his own development, seeing in Peanoâs logic more than a new âmathematical toolâ, describing Peano as a kind of proto-logicist, and defending him from PoincarĂ©âs criticisms. Especially in geometry, he vindicates several priority issues for Peanoâs school with respect to Hilbert in the philosophy of the axiomatic method
MolteplicitĂ potenziale e creativitĂ al tempo del computer: un matematico del 2000 legge Calvino
Taking into consideration Calvino's 1967 lecture "Cibernetica e fantasmi," the article discusses wheter the similarities between mathematics and literature previously noticed when reading Calvino's Six Memos for the Next Millennium (Lezioni americane) may be extended to include both central characteristics of 21st century mathematics and the mechanization of formal proofs