Contribució de Pietro Mengoli al concepte de límit a través d'una teoria de les quasi proporcions

El treball de recerca que aquí es presenta és l’estudi dels tres primers "elementa" de la "Geometriae Speciosae Elementa" (Bolonya, 1659) de Pietro Mengoli (1625-1686), que fou possiblement el deixeble més original de Bonaventura Cavalieri (1598-1647). En aquesta obra Mengoli desenvolupa un nou mètode per calcular quadratures utilitzant una teoria numèrica anomenada de “quasi proporcions”. Mengoli fonamenta les quasi proporcions en la teoria de proporcions del llibre cinquè dels "Elements" d’Euclides, a la qual hi afegeix unes nocions originals: raó “quasi nul•la”, “quasi infinita” i “quasi un nombre”. Una exhaustiva anàlisi d’aquesta teoria demostra l’originalitat de l’obra de Mengoli tant pel que fa a la seva forma d’exposició com pel que fa al seu contingut.

La censura de la obscenidad: Poggio Bracciolini y Pietro Aretino

El presente trabajo versa sobre dos obras italianas representativas de la literatura obscena, anticlerical e inmoral del Renacimiento y, por ende, prohibidas durante siglos. Las Confabulationes de Poggio Bracciolini y los XVI Modos de Pietro Aretino, a pesar del veto, tuvieron una difusión paneuropea y dejaron huellas en muchos textos además de configurar el género de la facecia en el caso poggiano y a reforzar, marcando pautas, otro, es decir el diálogo de cortesanas.

Síntesi en fase sólida d'oligosacàrids cardioactius

Estudi aproximatiu a la síntesi en fase sòlida de la part glicosídica de la digitoxina, essencial per l’activitat biològica com a reguladora de les propietats farmacocinètiques, i per tant molt important per l’avenç de la química mèdica i bioinorgànica. La metodologia que s’ha seguit inclou: síntesi de la pentosa de partença adequada, a partir de la qual, es van obtindre les unitats de 2,6- didesoxiglicósids; síntesi dels suports polimèrics necessaris per la síntesi en fase sòlida dels compostos objectiu; estudi de diferent tipus de glicosil dadors i activador de tioglicosids, lactols i tricloroacetimidats per la reacció de glicosilació amb el linker. S’ha assolit comprensió i coneixement de la tecnologia associada a la síntesi en fase sòlida, que requereix procediment diferenciat de la síntesi en solució convencional.

Technical innovations at the service of cheaper labour in pre-industrial Europe. The Enlightened agenda to transform the gender division of labour in silk manufacturing

In 1749, Jacques de Vaucanson patented his or tour pour tirer la soie or spindle for silk reeling. In that same year he presented his invention to the Academy of the Sciences in Paris, of which he was a member1. Jacques de Vaucanson was born in Grenoble, France, in 1709, and died in Paris in 1782. In 1741 he had been appointed inspector of silk manufactures by Louis XV. He set about reorganizing the silk industry in France, in considerable difficulty at the time due to foreign competition. Given Vaucanson’s position, his invention was intended to replace the traditional Piémontes method, and had an immediate impact upon the silk industry in France and all over Europe.

El diari de classe del mestre Ferran Rahola (curs 1935-36)

Ferran Rahola i Auguet va néixer a Girona el 14 de maig de 1914, fill primogènit de l'escriptor Carles Rahola i Llorens i de Rosa Auguet i Farró. Va viure i estudiar a la ciutat durant la seva infantesa i joventut, i després de cursar el batxillerat a l'institut va ingressar a estudiar magisteri a l'Escola Normal de Girona. Va iniciar els seus estudis el curs 1932-33 amb l'anomenat Pla Professional de 1931, el qual ha estat, en opinió deis estudiosos, el millor que han tingut les escoles normals d'Espanya, i responia al projecte global educatiu republicà, un dels pilars bàsics de la formació inicial de mestres. Es tractava d'uns estudis de magisteri professionals, amb un entroncament directe amb les escoles

Comprehensive evaluation of the IEEE 802.15.4 MAC layer performance with retransmissions

Supported by IEEE 802.15.4 standardization activities, embedded networks have been gaining popularity in recent years. The focus of this paper is to quantify the behavior of key networking metrics of IEEE 802.15.4 beacon-enabled nodes under typical operating conditions, with the inclusion of packet retransmissions. We corrected and extended previous analyses by scrutinizing the assumptions on which the prevalent Markovian modeling is generally based. By means of a comparative study, we singled out which of the assumptions impact each of the performance metrics (throughput, delay, power consumption, collision probability, and packet-discard probability). In particular, we showed that - unlike what is usually assumed - the probability that a node senses the channel busy is not constant for all the stages of the backoff procedure and that these differences have a noticeable impact on backoff delay, packet-discard probability, and power consumption. Similarly, we showed that - again contrary to common assumption - the probability of obtaining transmission access to the channel depends on the number of nodes that is simultaneously sensing it. We evidenced that ignoring this dependence has a significant impact on the calculated values of throughput and collision probability. Circumventing these and other assumptions, we rigorously characterize, through a semianalytical approach, the key metrics in a beacon-enabled IEEE 802.15.4 system with retransmissions.

Colloidal assembly on magnetically vibrated stripes

We investigate the collective organization of paramagnetic colloidal particles externally driven above the periodic stripes of a uniaxial ferrimagnetic garnet film. An external field modulation induces vibration of the stripe walls and produces random motion of the particles. Defects in the stripe pattern break the symmetry of the potential and favor particle nucleation into large clusters above a critical density. Mismatch between particle size and pattern wavelength generates assemblies with different morphological order. At even higher field strengths, repulsive dipolar interactions between the particles induce cluster melting. We propose a novel approach to generate and externally control a variety of colloidal assemblies.

Dynamics of a paramagnetic colloidal particle driven on a magnetic-bubble lattice

We present a theoretical study of the recently observed dynamical regimes of paramagnetic colloidal particles externally driven above a regular lattice of magnetic bubbles [P. Tierno, T. H. Johansen, and T. M. Fischer, Phys. Rev. Lett. 99, 038303 (2007)]. An external precessing magnetic field alters the potential generated by the surface of the film in such a way to either drive the particle circularly around one bubble, ballistically through the array, or in triangular orbits on the interstitial regions between the bubbles. In the ballistic regime, we observe different trajectories performed by the particles phase locked with the external driving. Superdiffusive motion, which was experimentally found bridging the localized and delocalized dynamics, emerge only by introducing a certain degree of randomness into the bubbles size distribution.

Reciprocal Translocations in Cattle: frequency estimation

Chromosomal anomalies, like Robertsonian and reciprocal translocations represent a big problem in cattle breeding as their presence induces, in the carrier subjects, a well documented fertility reduction. In cattle reciprocal translocations (RCPs, a chromosome abnormality caused by an exchange of material between nonhomologous chromosomes) are considered rare as to date only 19 reciprocal translocations have been described. In cattle it is common knowledge that the Robertsonian translocations represent the most common cytogenetic anomalies, and this is probably due to the existence of the endemic 1;29 Robertsonian translocation. However, these considerations are based on data obtained using techniques that are unable to identify all reciprocal translocations and thus their frequency is clearly underestimated. The purpose of this work is to provide a first realistic estimate of the impact of RCPs in the cattle population studied, trying to eliminate the factors which have caused an underestimation of their frequency so far. We performed this work using a mathematical as well as a simulation approach and, as biological data, we considered the cytogenetic results obtained in the last 15 years. The results obtained show that only 16% of reciprocal translocations can be detected using simple Giemsa techniques and consequently they could be present in no less than 0,14% of cattle subjects, a frequency five times higher than that shown by de novo Robertsonian translocations. This data is useful to open a debate about the need to introduce a more efficient method to identify RCP in cattle.

Human disease and drug pharmacology, complex as real life

In the past decades drug discovery practice has escaped from the complexity of the formerly used phenotypic screening in animals to focus on assessing drug effects on isolated protein targets in the search for drugs that exclusively and potently hit one selected target, thought to be critical for a given disease, while not affecting at all any other target to avoid the occurrence of side-effects. However, reality does not conform to these expectations, and, conversely, this approach has been concurrent with increased attrition figures in late-stage clinical trials, precisely due to lack of efficacy and safety. In this context, a network biology perspective of human disease and treatment has burst into the drug discovery scenario to bring it back to the consideration of the complexity of living organisms and particularly of the (patho)physiological environment where protein targets are (mal)functioning and where drugs have to exert their restoring action. Under this perspective, it has been found that usually there is not one but several disease-causing genes and, therefore, not one but several relevant protein targets to be hit, which do not work on isolation but in a highly interconnected manner, and that most known drugs are inherently promiscuous. In this light, the rationale behind the currently prevailing single-target-based drug discovery approach might even seem a Utopia, while, conversely, the notion that the complexity of human disease must be tackled with complex polypharmacological therapeutic interventions constitutes a difficult-torefuse argument that is spurring the development of multitarget therapies.

1,2,3,4-Tetrahydrobenzo[h][1,6]naphthyridines as a new family of potent peripheral-to-midgorge-site inhibitors of acetylcholinesterase: synthesis, pharmacological evaluation and mechanistic studies

A series of 1,2,3,4-tetrahydrobenzo[h][1,6]naphthyridines differently substituted at positions 1, 5, and 9 have been designed from the pyrano[3,2-c]quinoline derivative 1, a weak inhibitor of acetylcholinesterase (AChE) with predicted ability to bind to the AChE peripheral anionic site (PAS), at the entrance of the catalytic gorge. Fourteen novel benzonaphthyridines have been synthesized through synthetic sequences involving as the key step a multicomponent Povarov reaction between an aldehyde, an aniline and an enamine or an enamide as the activated alkene. The novel compounds have been tested against Electrophorus electricus AChE (EeAChE), human recombinant AChE (hAChE), and human serum butyrylcholinesterase (hBChE), and their brain penetration has been assessed using the PAMPA-BBB assay. Also, the mechanism of AChE inhibition of the most potent compounds has been thoroughly studied by kinetic studies, a propidium displacement assay, and molecular modelling. We have found that a seemingly small structural change such as a double O → NH bioisosteric replacement from the hit 1 to 16a results in a dramatic increase of EeAChE and hAChE inhibitory activities (>217- and >154-fold, respectively), and in a notable increase in hBChE inhibitory activity (> 11-fold), as well. An optimized binding at the PAS besides additional interactions with AChE midgorge residues seem to account for the high hAChE inhibitory potency of 16a (IC50 = 65 nM), which emerges as an interesting anti-Alzheimer lead compound with potent dual AChE and BChE inhibitory activities.

1,2,3,4-Tetrahydrobenzo[h][1,6]naphthyridines as a new family of potent peripheral-to-midgorge-site inhibitors of acetylcholinesterase: synthesis, pharmacological evaluation and mechanistic studies

A series of 1,2,3,4-tetrahydrobenzo[h][1,6]naphthyridines differently substituted at positions 1, 5, and 9 have been designed from the pyrano[3,2-c]quinoline derivative 1, a weak inhibitor of acetylcholinesterase (AChE) with predicted ability to bind to the AChE peripheral anionic site (PAS), at the entrance of the catalytic gorge. Fourteen novel benzonaphthyridines have been synthesized through synthetic sequences involving as the key step a multicomponent Povarov reaction between an aldehyde, an aniline and an enamine or an enamide as the activated alkene. The novel compounds have been tested against Electrophorus electricus AChE (EeAChE), human recombinant AChE (hAChE), and human serum butyrylcholinesterase (hBChE), and their brain penetration has been assessed using the PAMPA-BBB assay. Also, the mechanism of AChE inhibition of the most potent compounds has been thoroughly studied by kinetic studies, a propidium displacement assay, and molecular modelling. We have found that a seemingly small structural change such as a double O → NH bioisosteric replacement from the hit 1 to 16a results in a dramatic increase of EeAChE and hAChE inhibitory activities (>217- and >154-fold, respectively), and in a notable increase in hBChE inhibitory activity (> 11-fold), as well. An optimized binding at the PAS besides additional interactions with AChE midgorge residues seem to account for the high hAChE inhibitory potency of 16a (IC50 = 65 nM), which emerges as an interesting anti-Alzheimer lead compound with potent dual AChE and BChE inhibitory activities.

Climate change impacts on lakes: an integrated ecological perspective based on a multi-faceted approach, with special focus on shallow lakes

Freshwater ecosystems and their biodiversity are presently seriously threatened by global development and population growth, leading to increases in nutrient inputs and intensification of eutrophication-induced problems in receiving fresh waters, particularly in lakes. Climate change constitutes another threat exacerbating the symptoms of eutrophication and species migration and loss. Unequivocal evidence of climate change impacts is still highly fragmented despite the intensive research, in part due to the variety and uncertainty of climate models and underlying emission scenarios but also due to the different approaches applied to study its effects. We first describe the strengths and weaknesses of the multi-faceted approaches that are presently available for elucidating the effects of climate change in lakes, including space-for-time substitution, time series, experiments, palaeoecology and modelling. Reviewing combined results from studies based on the various approaches, we describe the likely effects of climate changes on biological communities, trophic dynamics and the ecological state of lakes. We further discuss potential mitigation and adaptation measures to counteract the effects of climate change on lakes and, finally, we highlight some of the future challenges that we face to improve our capacity for successful prediction.

Per què és bo perdonar?

TOTHOM S"HA SENTIT EMOCIONALMENT FERIT EN MÉS D"UNA OCASIÓ. Per un amic que ens ha decebut, per una acusació injusta... Davant d"aquestes emocions doloroses, sovint es reacciona amb irritació, hostilitat i desig de venjança. Després d"un temps de rancor, també hi ha qui decideix perdonar l"ofensorque no vol dir oblidar l"ofensa i renunciar al ressentiment. Hi ha persones molt més propenses que d"altres a gestionar els conflictes a través del perdó, i n"hi ha que se senten incapaces de fer-ho, la qual cosa les fa viure en un estat constant de còlera i d"emocions negatives que sovint requereix psicoteràpia, atès que l"angoixa que això els genera té importants conseqüències per a la salut. Pietro Petrini i els seus col·laboradors del Laboratori de Biologia Molecular i Bioquímica Clínica de la Universitat de Pisa (Itàlia) han publicat a Human Neuroscience el primer treball sobre la neuroanatomia funcional del perdó. Una de les principals conclusions és que la conseqüència final del perdó és retornar l"equilibri emocional i cognitiu a qui perdona.

Roma al tempo di Caravaggio.1600-1630

Quan l’any 1602 el pintor i tractadista Federico Zuccari publicà L’Ideade’pittori, scultori et architetti, Caravaggio ja havia radicalitzat el seu llenguatge versun fort naturalisme, al qual afegia un tractament de forts contrastos lumínics patent enl’obra, dos anys més tardana, que inaugura la mostra: La verge de Loreto, tambéconeguda com la Verge del peregrins. Davant el procés creatiu de Zuccari basat en laIdea, es a dir el disegno interno de bellesa, Caravaggio pren la realitat com a modeltrencant així amb el manierisme reformat que, a la Roma papal, te la seva plasmació al’Oratori dels Gonfalone on el citat tractadista hi va participar. D’altra banda la novamanera caravaggesca es contraria a la proposada per Annibale Carracci al programa dela Galeria Farnese i, alhora, per la defensada per tota la tractadística italiana del segleXVII, des de Giovanni Battista Agucchi, en el seu Tractat de la pintura(1607-1615),fins a Giovan Pietro Bellori en el seu discurs L’Idea del pittore, dello scultore edell’architetto, scelta dalle bellezze naturali superiore alla natura que seguint els vellsprincipis de la Poètica defensen que l’obra d’art ha de tenir versemblança, ha d’imitar els millors i pot corregir la realitat. No es estrany, doncs, que Agucchi posi comexemple a seguir l’art d’Annibale Carracci i que compari a Caravaggio amb l’escultorgrec Demetri, que va seguir tant al peu de la lletra la semblança que no va tenirconsideració per la bellesa.