Per una storia delle tecnologie dell'istruzione: l'aula scolastica

Nel corso dell'Ottocento l'edificio scolastico assunse un carattere istituzionale divenendo espressione della volontà statale di istruire in contesti formalizzati e laici, i propri cittadini. Le permanenze di precedenti modelli educativi resteranno, tuttavia, più o meno leggibili per molto tempo. Nell'articolo, che è stato pensato come materiale di supporto ad una lezione in videoconferenza con il prof. Piercesare Rivoltella dell'Università Cattolica, sui temi dei mutamenti nelle pratiche didattiche tra XIX e XXI secolo, si analizzano, sulla base di puntuali ricerche archivistiche, i cambiamenti nell'aula scolastica

Illiterates and criminals: judgements and prejudices about illiteracy in Sardinia (Italy) from the XIX to the XX century

Fight against illiteracy had inevitably relations with the events that saw the birth of Italy as a nation in the XIX century. Both the traditional education based on one oral method and the popular school of the new State had sometimes used different approaches especially in the southern areas of Italy and in the islands where the imposition of the national curriculum on the local administration couldn’t combine the local culture with the subsistence needs of the community. Compulsory primary school didn’t often start in harmony with the local dialects, the different cultures and the socio-economic needs. The “coercive” role of the national education didn’t help the people to attend the school especially where the new State wasn’t perfectly known The exemple of Sardinia is somehow emblematic because this island could keep its own identity although she had known several dominations. Here the national Italian curriculum (Casati law 1859) was seen worse than Carlo Felice’s, actually the second respected the cyclical agrarian calendar, including reading-writing-calculating methods, plus both an “agrarian catechism” and a Christian one. The lack of attention to the shepherds and farmers’ habits caused their absence from the compulsory school due to the need for rural work, for illnesses, and indigence (sons of widows, ill parents, lack of clothes and shoes, long distance from the school). The State’s answer to this “disobedience” sometimes explicit but mostly implicit shows the clear misunderstanding of the local culture. The census, the survey and their interpretations prove how it was difficult to overcome the simple correlation - peculiar to positivism - between illiteracy and crime “When the number of illiterates becomes fewer the number of prisoners will diminish”. Some intellectuals (ALFREDO NICEFORO, La delinquenza in Sardegna, 1897), considered Sardinia a criminal area because of the conformation of its inhabitants’ head. Illiteracy wasn’t a problem to fight at all. On one hand, a lot of soldiers, that died during the first world war, were from Sardinia and probably their low level of school education with the indigence made easier their recruitment. On the other hand, a lot of events of delinquency and banditry of the second world war were justified as acts of cultural backwardness of some inland villages in Sardinia. During the fifties, this simplification was changed by some intellectuals that described Sardinia richer and more problematic in their books (Pigliaru), anthropological research (Pinna), pictures (De Seta), novels (Giacobbe). The aim of my work is to explain how success and failure in literacy policy can also depend on understanding or misunderstanding of the social background by the public administration and government. When families recognize the importance of school education as a part of the local culture and as an economic opportunity they will encourage their children to study

Generation of fresh and pure random numbers for loophole-free Bell tests

We demonstrate extraction of randomness from spontaneous-emission events less than 36 ns in the past, giving output bits with excess predictability below $10^{-5}$ and strong metrological randomness assurances. This randomness generation strategy satisfies the stringent requirements for unpredictable basis choices in current "loophole-free Bell tests" of local realism [Hensen et al., Nature (London) 526, 682 (2015); Giustina et al., Phys. Rev. Lett. 115, 250401 (2015); Shalm et al., Phys. Rev. Lett. 115, 250402 (2015)].Comment: 4 pages + 11 supplementary, 5 + 10 figures (main + supplement

Ultrasensitive interferometric on-chip microscopy of transparent objects

Light microscopes can detect objects through several physical processes, such as scattering, absorption, and reflection. In transparent objects, these mechanisms are often too weak, and interference effects are more suitable to observe the tiny refractive index variations that produce phase shifts. We propose an on-chip microscope design that exploits birefringence in an unconventional geometry. It makes use of two sheared and quasi-overlapped illuminating beams experiencing relative phase shifts when going through the object, and a complementary metal-oxide-semiconductor image sensor array to record the resulting interference pattern. Unlike conventional microscopes, the beams are unfocused, leading to a very large field of view (20 mm(2)) and detection volume (more than 0.5 cm(3)), at the expense of lateral resolution. The high axial sensitivity (<1 nm) achieved using a novel phase-shifting interferometric operation makes the proposed device ideal for examining transparent substrates and reading microarrays of biomarkers. This is demonstrated by detecting nanometer-thick surface modulations on glass and single and double protein layers.Peer ReviewedPostprint (published version

Electric-field thermally poled optical fibres for quasi-phase-matched second harmonic generation

We report on quasi-phase-matched frequency doubling to the blue in electric-field poled optical fibres. An increase of a factor of ~10 in the conversion efficiency in comparison with the previous results is obtained. Our experiments show that the structure of the induced nonlinear grating is not uniform, both longitudinally and transversely. For this reason the value of the effective nonlinear coefficient is still far from the optimum expected from the measured value, through Maker's oscillation, for a uniformly poled fibre

Frequency doubling in Ga:La:S optical glass with microcrystals

Second harmonic generation in gallium-lanthanum-sulphide (Ga:La:S) and GeS2+Ga:La:S glasses is investigated. It is shown that microcrystals of Ga:La:S and of alpha-phase of gallium-sulphide (alpha-Ga2S3), whose presence in the glass matrix is revealed by x-ray diffraction analysis, are responsible for the frequency doubling process

Frequency conversion of structured light

We demonstrate the coherent frequency conversion of structured light, optical beams in which the phase varies in each point of the transverse plane, from the near infrared (803nm) to the visible (527nm). The frequency conversion process makes use of sum-frequency generation in a periodically poled lithium niobate (ppLN) crystal with the help of a 1540-nm Gaussian pump beam. We perform far-field intensity measurements of the frequency-converted field, and verify the sought-after transformation of the characteristic intensity and phase profiles for various input modes. The coherence of the frequency-conversion process is confirmed using a mode-projection technique with a phase mask and a single-mode fiber. The presented results could be of great relevance to novel applications in high-resolution microscopy and quantum information processing

How “beneficial” virus of popular education “contaminated” Sardinia island, in the first half of the 19th century

Popular education has played an important role in order to build the national Italian identity. Many researchers show that, after unification of Italy (1861), the government paid attention to primary schools: teachers not only taught reading, writing and calculating but also spread new values such as patriotism, positivism, rationalism. The aim of my paper is to study this kind of schools in the first half of 19th century, when Italy was shared in many States, everyone with different education policies. I’m going to concentrate my attention on an independent and isolated region: Sardinia. In natural history, islands are quite interesting because scientists can study autochthon species and understand when local environment keeps in contact with outside ecosystems. I think historians can do what scientists do, if they want to investigate the beginning of popular school in Sardinia. After four centuries of Spanish domination, in 1720, the island passed under the rule of Vittorio Amedeo II of Savoia, prince of Piemonte, member of the Sabaudi dynasty. Only after a century of Savoia domination, the kings Carlo Felice and Carlo Alberto could begin a systematic program of reforms that was continued after the unification of Italy in 1861. The popular school called “scuola normale” arrived in Sardinia with the school reforms in 1822-1824. The aim of my paper is to show how and when models, coming from abroad, mixed with the presence of congregations of teachers, not only Jesuits, who were very active in the education of the ruling classes, but also Piarists who settled in many villages, giving life to an efficient school system made up of boarding schools, seminaries and private teaching posts. My research is founded on letters sent between: Francesco Cherubini and Antonio Manunta in the early XIX century. The first translated education books coming from Austria into Italian and tried to use simultaneous education methodology in a popular school that he founded in Milan; the second learnt from Cherubini new didactic models to instruct a maximum number of pupils at the same time and made many efforts to import them to the island. My study case is interesting such as a laboratory test: according to me, Sardinia - set in the middle of Mediterran - is a good point of view to analyze the impact of the “beneficial” virus (popular education) that “contaminated” all Europe from the end of 18th century

An antireflection transparent conductor with ultralow optical loss (o2 %) and electrical resistance (o6O 2)

Transparent conductors are essential in many optoelectronic devices, such as displays, smart windows, light-emitting diodes and solar cells. Here we demonstrate a transparent conductor with optical loss of B1.6%, that is, even lower than that of single-layer graphene (2.3%), and transmission higher than 98% over the visible wavelength range. This was possible by an optimized antireflection design consisting in applying Al-doped ZnO and TiO2 layers with precise thicknesses to a highly conductive Ag ultrathin film. The proposed multilayer structure also possesses a low electrical resistance (5.75O 2), a figure of merit four times larger than that of indium tin oxide, the most widely used transparent conductor today, and, contrary to it, is mechanically flexible and room temperature deposited. To assess the application potentials, transparent shielding of radiofrequency and microwave interference signals with B30 dB attenuation up to 18 GHz was achieved.Peer ReviewedPostprint (author's final draft

55% conversion efficiency to green in bulk quasi-phase-matching lithium niobate

High voltage and liquid electrodes were used for periodic poling of lithium niobate. A sample with a period of 6.80 µm was used for first-order frequency doubling of 1064 nm Q-switched Nd:YAG light with an average power conversion of 55%, implying greater than 90% power conversion at the peak of the pulse. The effective nonlinear coefficient for both Q-switched and continuous-wave measurements was ~15 pm/V