Parametric attosecond pulse amplification far from the ionization threshold from high order harmonic generation in He+^+

Parametric amplification of attosecond coherent pulses around 100 eV at the single-atom level is demonstrated for the first time by using the 3D time-dependent Schr{\"o}dinger equation in high-harmonic generation processes from excited states of He$^+$. We present the attosecond dynamics of the amplification process far from the ionization threshold and resolve the physics behind it. The amplification of a particular central photon energy requires the seed XUV pulses to be perfectly synchronized in time with the driving laser field for stimulated recombination to the He$^+$ ground state and is only produced in a few specific laser cycles in agreement with the experimental measurements. Our simulations show that the amplified photon energy region can be controlled by varying the peak intensity of the laser field. Our results pave the way to the realization of compact attosecond pulse intense XUV lasers with broad applications

Towards Ethical AI: Mathematics Influences Human Behavior

Mathematics plays an important role in the linguistic structure of artificial in- telligence (AI). We describe the linguistic process as a unique structure present both in human cognition and in cognitive computing. The close relationship with both AI and human cognition is due to this unique structure, which paves the way for AI to interfere with the behavior of those who interact with it. We highlight the role of mathematicians in designing algorithms—the core of the AI linguistic process—and in defining steps and instructions for AI. Because al- gorithms, through AI, interfere with the thought of those who interact with AI by providing anticipated solutions that prevent users from making free choices, we investigate how we can apply ethical principles to guide interactions between users and intelligent systems in order to address this issue. We contend that by integrating ethical principles in the mathematical modeling of algorithms, we can avoid manipulation, inequality, and black boxes in the protection of individual rights. As such, ethical considerations are highly important for those working with algorithms, which highlights the humanistic side of mathematics

Una experiència d'aprenentatge basat en problemes en enginyeria del software

El departament de Ciències de la Computació imparteix des de fa força anys l'assignatura d'enginyeria del software a les titulacions superior i tècnica d'enginyeria informàtica. Fins el curs passat, la metodologia docent era la "tradicional": classes magistrals de teoria, classes de problemes i pràctiques de laboratori, amb una avaluació en que un examen escrit té el major pes. El nostre convenciment que l'estudiant aprenia molt menys del que era possible i necessari, més les idees aportades per un dels cursos de formació del IDES, ens ha portat a experimentar durant el curs 2005-06 una adaptació de l'enfocament d'aprenentatge basat en resolució de problemes. En aquesta comunicació exposem breument els continguts de la assignatura, els motius d'aquest canvi, el nou mètode docent emprat i la valoració (globalment molt positiva) que en fem tant els professors de la assignatura com els estudiants

Anàlisi econòmica financera del sector vinícola català

Objecte: El present treball reflecteix l'anàlisi econòmica financera de les grans indústries elaboradores de vi a Catalunya en el període 2008-2012. S'ha considerat la indústria vinícola per ser un sector estratègic dintre de l'agroalimentació catalana, considerada primer clúster agroalimentari d'Europa segons dades de l'observatori de clústers de l'Stockholm School of Economics. L'estudi posiciona aquestes indústries dintre del sector agroalimentari català i espanyol i presenta els principals indicadors econòmics i financers per tal de diagnosticar la salut d'aquestes empreses en el període 2008-2012 mitjançant una anàlisi a curt i llarg termini, una anàlisi de resultats i una anàlisi dels canvis patrimonials i dels fluxos d'efectiu de les empreses vinícoles. Disseny/metodologia: Les dades utilitzades provenen dels estats comptables de les indústries vinícoles en el període 2008-2012, en concret, es recull una mostra d'empreses catalanes que elaboren vi amb uns ingressos d'explotació mínims de 5.700.000 € i uns actius mínims de 2.850.000 €, que presenten comptes anuals normals seguint el que disposa el Pla General Comptable en aquest període, i que majoritàriament són grans empreses sobre les que es porta a terme l'anàlisi econòmic financer mitjançant l'estadística descriptiva oportuna arribant a uns resultats i conclusions. Aportacions i resultats: L'estudi permet assenyalar que les empreses vinícoles en aquest període gaudeixen d'una bona salut econòmica i financera, amb un reduït nombre d'empreses que concentren gran part de les vendes. Tot i que les vendes hanaugmentat, s'experimenta una reducció dels resultats econòmics per l'augment de les despeses d'explotació en aquest període. Per tant, no gaudeixen d'una gestió eficient de les despeses. Limitacions: Seria convenient estendre la mostra a petites empreses vinícoles i arribar fins a dades actuals per confirmar els canvis de tendència en l'anàlisi econòmica i financera. Implicacions pràctiques: Permet valorar la projecció d'aquest sector en els últims anys a Catalunya, per prendre les oportunes decisions econòmiques al respecte. Implicacions socials: Els resultats permeten posar de manifest canvis que cal fer en el sector, per tal de que les empreses segueixin ben posicionades. Valor afegit: Per les associacions, cooperatives i empreses vinícoles en general, dóna informacions econòmiques i financeres rellevants de la salut empresarial de les empreses del vi en aquest difícil període, amb indicacions a seguir per assolir els reptes de futur

Modified Periodic Acid-Schiff (PAS) Is an Alternative to Safranin O for Discriminating Bone–Cartilage Interfaces

Cartilage histomorphometry is often performed on decalcified, paraffin-embedded bone sections, which provide versatility in staining applications from basic morphology to immunohistochemistry. Safranin O is a cationic dye that binds to proteoglycans in cartilage and is routinely used to assess growth plate dynamics and/or fracture repair at bone–cartilage interfaces. When used with a counterstain such as fast green, safranin O can offer exquisite differentiation of cartilage from surrounding bone. However, various decalcification and processing methods can deplete proteoglycans, rendering inconsistent, weak, or absent safranin O staining with indiscriminate bone–cartilage boundaries. We sought to develop an alternative staining methodology that preserves the contrast of bone and cartilage in cases of proteoglycan depletion that can be applied when other cartilage stains are unsuccessful. Here, we describe and validate a modified periodic acid-Schiff (PAS) protocol that we developed using Weigert\u27s iron hematoxylin and light green stains as an alternative to safranin O for discriminating bone–cartilage interfaces of skeletal tissues. This method provides a practical solution for differentiating bone and cartilage when safranin O staining is not detected after decalcification and paraffin processing. The modified PAS protocol can be useful for studies in which identification of the bone–cartilage interface is essential but may not be preserved with standard staining approaches

Karst in conglomerates in Catalonia (Spain): morphological forms and sedimentary sequence types recorded on archaeological sites

This article aims to make the karst morphological forms to be found in conglomerate rocks, as well as the sedimentary sequence types recorded in such deposits, more widely known. Particular attention is paid to points where prehistoric occupation has been traced, sites such as: the Font Major Cave (Espluga de Francoli, Tarragona), the Hort de la Boquera, the Filador Rock-shelter and the Colls Rock-shelter (Margalef de Montsant, Tarragona), and the Parco Cave (Alôs de Balaguer, Lleida). By means of this approach the characteristics of karst deposits in conglomerate rocks are analyzed both from an archaeological and a sedimentary point of view

A dynamic pricing algorithm for a network of virtual resources

A service chain is a combination of network services (e.g. network address translation (NAT), a firewall, etc.) that are interconnected to support an application (e.g. video-on-demand). Building a service chain requires a set of specialized hardware devices each of which need to be configured with their own command syntax. By moving management functions out of forwarding hardware into controller software, software-defined networking (SDN) simplifies provisioning and reconfiguration of service chains. By moving the network functions out of dedicated hardware devices into software running on standard x86 servers, network function virtualization (NFV) turns the deployment of a service chain into a more (cost)-efficient and flexible process. In an SDN/NFV-based architecture, those service chains are composed of virtual network functions (VNFs) that need to be mapped to physical network components. In literature, several algorithmic approaches exist to do so efficiently and cost-effectively. However, once mapped, a simple revenue model is used for pricing the requested substrate resources. This often leads to a loss of revenue for the infrastructure provider. In this paper, we propose a more advanced, dynamic pricing algorithm for pricing the requested substrate resources. The proposed algorithm increases the infrastructure provider's revenue based on historic data, current infrastructure utilization levels and the pricing of competitors. Our experimental evaluation shows that the proposed algorithm increases the revenue of the infrastructure provider significantly, independent of the average network utilization.Peer Reviewe

Development and structural validation of a scale to assess regulation of anger and sadness in interpersonal situations

The purpose of this research was to develop and validate a new instrument to assess the regulation of anger and sadness in interpersonal situations, covering a wide range of emotion regulation strategies. Two studies were carried out, both of them using purposively selected samples. In Study 1 we created a set ofitems based on previous studies of emotion regulation, applied a preliminary version of this scale to a pilot sample of undergraduate students (n = 400), and then selected, using exploratory factor analysis (EFA), the best 28 items to include in a brief version of the instrument, the Scale of Emotion Regulation in Interpersonal Situations (SERIS). In Study 2 we tested the resulting scale ina new sample of undergraduate students (n = 259) by means of confirmatory factor analysis. Study 2 validated the factor structure identified in the EFA. Results showed that the scale has adequate internal consistency and psychometric properties. The new scale also identifies the strategies that are most frequently used in the anger and sadness scenarios, showing differential patterns which are consistent with previous literature on emotion regulation. We discuss the limitations of the study and acknowledge that future studies addressing the scale's convergent and discriminant validity are now required

Review of multivariate survival data

Document de recerca publicat per la UPC. Departament d'Estadística i Investigació operativaThis paper reviews some of the main contributions in the area of multivariate survival data and proposes some possible extensions. In particular, we have concentrated our search and study on those papers that are relevant to the situation where two (or more) consecutive variables are followed until a common day of analysis and subject to informative censoring. The paper reviews bivariate nonparametric approaches and extend some of them to the case of two nonconsecutive times. We introduce the notation and construct the likelihood for the general problem of more than two consecutive survival times. We formulate the time dependencies and trends via a Bayesian approach. Finally, three regression models for multivariate survival times are discussed together with the differences among them which will be useful when the main interest is on the effect of covariates on the risk of failure.Postprint (author’s final draft