1,790 research outputs found

    Historical and Epistemological Reflections on the Culture of Machines around the Renaissance: Machines, Machinaries and Perpetual Motion. Seconda parte

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    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

    Regressivity reducing VAT reforms

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    A concern about a more extensive use of the Value Added Tax (VAT) in national tax systems often arises both from its impact on aggregate consumption and its alleged regressivity over income. Yet, the empirical evidence on this latter issue is still narrow mainly due to the lack of joint data on income and expenditures with enough detail to account for commodity-specific tax rates. After discussing relevant problems in the measurement of VAT incidence over current income – which are likely to cause severe upward bias in the estimated regressivity – the paper aixsms at analysing the distributional implications of different VAT structures. In a framework of marginal tax reforms, relying on the concept of Gini elasticity (Yitzhaki, 1983), a general methodology is proposed to analyse and improve the distributional profile of VAT over income. Using a static microsimulation model (EGaLiTe), the methodology is applied on a comprehensive dataset of expenditures and incomes obtained by a statistical matching of two different sources representative of the Italian population. It is shown that an alternative allocation of goods among existing rates could mitigate the regressive profile of the tax over income, and that a properly designed two-rate setting could even improve the distributional outcome compared with the current setting. Finally, behavioural responses to tax-driven price changes are also simulated in order to assess the potential impact of the proposed reforms on aggregate expenditures

    Synthesis and characterization of trans-di-(4-pyridyl)porphyrin dimers

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    Preparation and characterization of a small library of symmetric trans-di(4-pyridyl) porphyrin dimers, obtained by either Glaser\u2013Hay or Sonogashira coupling reactions from appropriately prepared trans-di-4-pyridylporphyrin precursors, is presented. The porphyrin dimers are differentiated by a phenyl-alkynyl bridge of increasing length at one meso-position, while for all the derivatives the two remaining opposite meso-positions are tailored with a phenyl moiety bearing a short polyether chain. Coordination of the four pyridyl groups with appropriate metal fragments may be exploited to construct tubular hollow structures, with varied internal sizes, depending on the choice of the porphyrin dimer component

    Can IDO activity predict primary resistance to anti-PD-1 treatment in NSCLC?

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    BACKGROUND: Immune checkpoint inhibitors have revolutionized the treatment paradigm of highly lethal malignancies like advanced non-small cell lung cancer (NSCLC), demonstrating long-term tumour control and extended patient survival. Unfortunately, only 25-30% of patients experience a durable benefit, while the vast majority demonstrate primary or acquired resistance. Recently, indoleamine 2,3-dioxygenase (IDO) activity has been proposed as a possible mechanism of resistance to anti-PD-1 treatment leading to an immunosuppressive microenvironment. METHODS: Pre-treatment serum concentrations of tryptophan (trp) and kynurenine (kyn) were measured by high-performance liquid chromatography tandem mass spectrometry in NSCLC patients treated with second-line nivolumab. The IDO activity was expressed with kyn/trp ratio. The associations between kyn/trp ratio and early progression, performance status (PS), age, sex, brain metastases, pleural effusion, progression free survival (PFS) and overall survival (OS) were analyzed using Spearman test and Mann-Whitney test. RESULTS: Twenty-six NSCLC patients were included in our study; 14 of them (54%) presented early progression (< 3 months) to nivolumab treatment. The median value of kyn/trp ratio was 0.06 µg/ml and the median value of quinolinic acid was 68.45 ng/ml. A significant correlation between early progression and higher kyn/trp ratio and quinolinic acid concentration was observed (p = 0.017 and p = 0.005, respectively). Patients presenting lower values of kyn/trp ratio and quinolinic acid levels showed longer PFS (median PFS not reached versus 3 months; HR: 0.3; p = 0.018) and OS (median OS not reached vs 3 months; HR: 0.18; p = 0.0005). CONCLUSION: IDO activity, expressed as kyn/trp ratio, is associated with response to immunotherapy; in particular, higher kyn/trp ratio could predict resistance to anti-PD-1 treatment. These preliminary results suggest the possibility of using anti-PD-1 plus IDO inhibitor in those patients with high level of kyn/trp ratio

    Introduction. 1564-2014. Homage to Galileo Galilei

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    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..

    A rare localization of papillary fibroelastoma

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    Papillary fibroelastoma is a benign cardiac tumor, generally small and with papillary fronds, third in frequency after cardiac myxoma and lipoma, with a prevalence of about 10% of all cardiac tumors [1, 2]. Its localization, similarly to other benign cardiac tumors, prefers the endothelium of the valve leaflets, most commonly the aortic valve (44% to 59%), less frequently the mitral (13% to 35%) and tricuspid (4% to 15%) valves [3–5]. It is discovered occasionally or following symptoms due to systemic or coronary embolization. Symptoms due to obstruction of the ventricular flow tract are rare. Surgical excision is curative and its recurrence rare if the resection of margins are disease-free

    Chlamydia trachomatis versus common uropathogens as a cause of chronic bacterial prostatitis: Is there any difference? Results of a prospective parallel-cohort study

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    Purpose: The role of Chlamydia trachomatis (CT) infection in chronic bacterial prostatitis (CBP) is well known. What is unclear is whether there are any differences in the course or clinical outcome of the disease when the cause is CT or other uropathogens. Materials and Methods: A series of 311 patients affected by CBP due to CT (cohort A) was compared with a group of 524 patients affected by CBP caused by common uropathogen bacteria (cohort B). All participants completed the following questionnaires: National Institutes of Health Chronic Prostatitis Symptom Index, International Prostate Symptom Score, International Index of Erectile Function-15 erectile function domain (IIEF-15-EFD), Premature Ejaculation Diagnostic Tool (PEDT), and the Short Form 36 (SF-36) Health Survey. All patients were followed with clinical and microbiological evaluations. Results: After a mean follow-up time of 42.3 months, the number of symptomatic episodes was significantly higher in patients in cohort A than in cohort B (4.1±1.1 vs. 2.8±0.8, p<0.001), and the mean time to first symptomatic recurrence was shorter in cohort A than in cohort B (3.3±2.3 months vs. 5.7±1.9 months, p<0.001). Moreover, scores on the SF-36 tool were significantly lower in cohort A (96.5±1.0 vs. 99.7±1.9, p<0.001) at the first symptomatic recurrence. Cohort A also showed significantly lower scores on the IIEF-15-EFD and PEDT questionnaires at the end of the follow-up period (26.8±2.9 vs. 27.3±3.3, p=0.02 and 11.5±2.3 vs. 4.5±2.8, p<0.001, respectively). Conclusions: Patients affected by CBP due to CT infection have a higher number of symptomatic recurrences with a more severe impact on quality of life

    Nonischemic left ventricular scar and cardiac sudden death in the young

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    Nonischemic Left Ventricular Scar (NLVS) is a pattern of myocardial injury characterized by midventricular and/or subepicardial gadolinium hyper enhancement at cardiac magnetic resonance, in absence of significant coronary artery disease. We aimed to evaluate the prevalence of NLVS in juvenile sudden cardiac death and to ascertain its aetiology at autopsy. We examined 281 consecutive cases of sudden death of subjects aged 1 to 35 years of age. NLVS was defined as a thin, grey rim of subepicardial and/or midmyocardial scar in the left ventricular free wall and/or the septum, in absence of significant stenosis of coronary arteries. NLVS was the most frequent finding (25%) in sudden deaths occurring during sports. Myocardial scar was localized most frequently within the left ventricular posterior wall, and affected the subepicardial myocardium, often extending to the midventricular layer. On histology it consisted of fibrous or fibro-adipose tissue. Right ventricular involvement was always present. Patchy lymphocytic infiltrates were frequent. Genetic and molecular analyses clarified the aetiology of NLVS in a subset of cases. ECG recordings were available in over half of subjects. The most frequent abnormality was the presence of low QRS voltages (< 0,5 mV) in limb leads. In serial ECG tracings, the decrease in QRS voltages appeared, in some way progressive. NLVS is the most frequent morphologic substrate of juvenile cardiac sudden death in sports. It can be suspected based on ECG findings. Autopsy study and clinical screening of family members are required to differentiate between Arrhythmogenic Right Ventricular Cardiomyopathy/Dysplasia and chronic acquired myocarditis

    Observing CMB polarisation through ice

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    Ice crystal clouds in the upper troposphere can generate polarisation signals at the uK level. This signal can seriously affect very sensitive ground based searches for E- and B-mode of Cosmic Microwave Background polarisation. In this paper we estimate this effect within the ClOVER experiment observing bands (97, 150 and 220 GHz) for the selected observing site (Llano de Chajnantor, Atacama desert, Chile). The results show that the polarisation signal from the clouds can be of the order of or even bigger than the CMB expected polarisation. Climatological data suggest that this signal is fairly constant over the whole year in Antarctica. On the other hand the stronger seasonal variability in Atacama allows for a 50% of clean observations during the dry season.Comment: 7 Pages, 4 figure

    A polarization modulator unit for the mid- and high-frequency telescopes of the LiteBIRD mission

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    The LiteBIRD mission is a JAXA strategic L-class mission for all sky CMB surveys which will be launched in the 2020s. The main target of the mission is the detection of primordial gravitational waves with a sensitivity of the tensor-to-scalar ratio δr&lt;0.001. The polarization modulator unit (PMU) represents a critical and powerful component to suppress 1/f noise contribution and mitigate systematic uncertainties induced by detector gain drift, both for the high-frequency telescope (HFT) and for the mid-frequency telescope (MFT). Each PMU is based on a continuously-rotating transmissive half-wave plate (HWP) held by a superconducting magnetic bearing in a 5K environment. In this contribution we will present the design and expected performance of the LiteBIRD PMUs and testing performed on every PMU subsystem with a room-temperature rotating disk used as a stand-in for the cryogenic HWP rotor
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