Sant Pere de Rodes i l’arquitecte de Carlemany

L’arquitectura de l’església de Sant Pere de Rodes es pot explicar dins de la tradició carolíngia i connota un significat; tant el programa iconogràfic com la forma estricta es poden relacionar amb l’arquitectura representada a les grans bíblies de Rodes i de Ripoll, il•lustrades mentre es construïa l’edifici; i el sistema proporcional usa les elaboracions aritmètiques compilades per Boeci al segle VI. Hi ha casos d’un maneig semblant de les descripcions bíbliques i la ciència dels nombres en esglésies anteriors i coetànies. Iconografia i proporció revelen que l’ordre espacial és el resultat de les relacions de posició entre els elements, i no de cap articulació de peces ni repetició de mòduls.Architecturally the church of Sant Pere de Rodes belongs in the carolingian tradition; it connotes a specific meaning; both its iconographic programme and its form may be related to architectural representations in the bibles of Rodes and Ripoll which were drawn while the building was being built; the proportional system uses arithmetic developments compiled in the 6th century by Boethius. Similar uses of biblical descriptions and the science of number may be found in older and contemporary buildings. As Iconography and proportion reveal, the order of space is a result of relations of position among elements and has nothing to do with room articulation or module repetition

El primer arquitecte Sant Pere de Rodes: projectar una església fa deu segles

L’objectiu és determinar què era l’església del monestir de Sant Pere de Rodes en el seu primer estat acabat per a qui la vagi concebre i dirigir. N’hem manejat la historiografia i les dificultats de veure’n la forma, aixecat plànols, trobat la unitat de mesura, estudiat les dimensions en relació amb els coneixements de proporció del moment i les descripcions dels edificis bíblics, seguit les variacions durant la construcció, contextualitzat el vocabulari, descrit l’estructura espacial i el programa iconològic. En resulta que per haver concebut, elaborat i construït l’església calien el quadrivi, la Bíblia, la idea dels sentits múltiples establerta per l’exegesi i un coneixement poc o molt analític d’arquitectura romana i d’arrel romana; i la capacitat de treure’n criteris de decisió de rang equivalent; les columnes superposades de la nau són el moment fort de la constitució de l’edifici en lloc.The aim is to establish what the nature was of the church of the monastery of Sant Pere de Rodes for those in charge of its conception and actual construction when the building was first considered complete. We have examined the historiography and the difficulties encountered in describing the form of the church, measured the building, drawn new plans, found the unit used, related the dimensions to contemporary knowledge on proportion and biblical descriptions, followed changes during the building process, put the vocabulary in context and described both the spatial structure and the iconological program. The church could neither have been conceived, developed nor built without the quadrivium, the Bible, the exegetical idea of multiplicity of senses and an analytical knowledge of Roman or Romanbased architecture; nor without the ability to get equivalent decision criteria from all of them. The superimposed columns make the building into a place.Postprint (published version

Synoptic attributions of extreme precipitation in the Atacama Desert (Chile)

Northern Chile is a region characterised by an extremely dry climate; however, there is a brief rainy season from December to March (austral summer), mainly above 3000 m a.s.l. It is interesting to consider where the humid air masses that generate such rain come from. For this purpose, daily precipitation data from 161 meteorological stations located in this area (18° S–19° S) were considered, and four clusters formed by k-means clustering. For each cluster, days of extreme precipitation (above 90th percentile) were selected to obtain flow strength (F), direction (D), and vorticity (Z) for each event according to the Jenkinson and Collison (JC) method. The back trajectory, for the previous 72 h, of air masses affecting the centroid of each cluster was determined by means of the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model. The analyses were carried out at sea level (1013 hPa) and in the middle (500 hPa) and upper (250 hPa) troposphere. Surface circulation was not a determining factor in the occurrence of extreme events, but it did influence circulation at 500 and 250 hPa. For stations located in the northern Altiplano, moisture advection from the Amazon basin is evident due to the configuration of the Bolivian high—an upper level anticyclone that develops over the Bolivian Altiplano during austral summer. For stations located in the southern part of the study area, the main source of moisture is the Pacific Ocean, and the weather is related to the arrival of frontal systems and to the configuration of cut-off low pressure systems in the mid-troposphere.The authors want to thank the FONDECYT Project 11160059 of the Chilean Government, the Climatology Group (2017SGR1362, Catalan Government) and the CLICES Project (CGL2017-83866-C3-2-R) for the institutional support. R.S.N. is funded by the Spanish Ministry of Science and Innovation (grant no. FJCI-2017-31595)

Observation of activity prior to dielectric breakdown in liquid xenon with the XeBrA experiment

Maintaining the electric fields necessary for the current generation of noble liquid time projection chambers (TPCs), with drift lengths exceeding one meter, requires a large negative voltage applied to their cathode. Delivering such high voltage is associated with an elevated risk of electrostatic discharge and electroluminescence, which would be detrimental to the performance of the TPC. The Xenon Breakdown Apparatus (XeBrA) is a five-liter high-voltage test chamber built to investigate the factors contributing to high voltage breakdown in noble liquids. Area scaling and surface finish were observed to be the dominant factors affecting breakdown. In addition, small electrical activity was frequently observed during high voltage ramps prior to electrostatic discharge. The position of breakdowns was reconstructed with a system of high-speed cameras and good agreement with electric field simulations was found. Based on the results presented in this work, we recommend that the next generation of TPCs should not withstand fields larger than 20 kV/cm on the electrode surfaces.Comment: 29 pages, 13 figures; typo in the author list correcte

CH-01 is a hypoxia-activated prodrug that sensitizes cells to hypoxia/reoxygenation through inhibition of Chk1 and aurora A

The increased resistance of hypoxic cells to all forms of cancer therapy presents a major barrier to the successful treatment of most solid tumors. Inhibition of the essential kinase Checkpoint kinase 1 (Chk1) has been described as a promising cancer therapy for tumors with high levels of hypoxia-induced replication stress. However, as inhibition of Chk1 affects normal replication and induces DNA damage, these agents also have the potential to induce genomic instability and contribute to tumorigenesis. To overcome this problem, we have developed a bioreductive prodrug, which functions as a Chk1/Aurora A inhibitor specifically in hypoxic conditions. To achieve this activity, a key functionality on the Chk1 inhibitor (CH-01) is masked by a bioreductive group, rendering the compound inactive as a Chk1/Aurora A inhibitor. Reduction of the bioreductive group nitro moiety, under hypoxic conditions, reveals an electron-donating substituent that leads to fragmentation of the molecule, affording the active inhibitor. Most importantly, we show a significant loss of viability in cancer cell lines exposed to hypoxia in the presence of CH-01. This novel approach targets the most aggressive and therapy-resistant tumor fraction while protecting normal tissue from therapy-induced genomic instability. © 2013 American Chemical Society

Nuclear recoil response of liquid xenon and its impact on solar 8B neutrino and dark matter searches

Knowledge of the ionization and scintillation responses of liquid xenon (LXe) to nuclear recoils is crucial for LXe-based dark matter experiments. Current calibrations carry large uncertainties in the low-energy region below $\sim3$ keV$_nr$ where signals from dark matter particles of $<$10 GeV/c$^2$ masses are expected. The coherent elastic neutrino-nucleus scattering (CE$\nu$NS) by solar $^8$B neutrinos also results in a continuum of nuclear recoil events below 3.0 keV$_{nr}$ (99\% of events), which further complicates low-mass dark matter searches in LXe experiments. In this paper, we describe a method to quantify the uncertainties of low-energy LXe responses using published calibration data, followed by case studies to evaluate the impact of yield uncertainties on ${^8}$B searches and low-mass dark matter sensitivity in a typical ton-scale LXe experiment. We conclude that naively omitting yield uncertainties leads to overly optimistic limits by factor $\sim2$ for a 6 GeV/c$^2$ WIMP mass. Future nuclear recoil light yield calibrations could allow experiments to recover this sensitivity and also improve the accuracy of solar ${^8}$B flux measurements

RASSF1A–LATS1 signalling stabilizes replication forks by restricting CDK2-mediated phosphorylation of BRCA2

Genomic instability is a key hallmark of cancer leading to tumour heterogeneity and therapeutic resistance. ​BRCA2 has a fundamental role in error-free DNA repair but also sustains genome integrity by promoting ​RAD51 nucleofilament formation at stalled replication forks. ​CDK2 phosphorylates ​BRCA2 (pS3291-​BRCA2) to limit stabilizing contacts with polymerized ​RAD51; however, how replication stress modulates ​CDK2 activity and whether loss of pS3291-​BRCA2 regulation results in genomic instability of tumours are not known. Here we demonstrate that the Hippo pathway kinase ​LATS1 interacts with ​CDK2 in response to genotoxic stress to constrain pS3291-​BRCA2 and support ​RAD51 nucleofilaments, thereby maintaining genomic fidelity during replication stalling. We also show that ​LATS1 forms part of an ​ATR-mediated response to replication stress that requires the tumour suppressor ​RASSF1A. Importantly, perturbation of the ​ATR–​RASSF1A–​LATS1 signalling axis leads to genomic defects associated with loss of ​BRCA2 function and contributes to genomic instability and ‘BRCA-ness’ in lung cancers