Bott-Chern Harmonic Forms on Stein Manifolds

Let $M$ be an $n$-dimensional $d$-bounded Stein manifold $M$, i.e., a complex $n$-dimensional manifold $M$ admitting a smooth strictly plurisubharmonic exhaustion $\rho$ and endowed with the K\"ahler metric whose fundamental form is $\omega=i\partial\overline{\partial}\rho$, such that $i\overline{\partial}\rho$ has bounded $L^\infty$ norm. We prove a vanishing result for $W^{1,2}$ harmonic forms with respect to the Bott-Chern Laplacian on $M$.Comment: 11 page

Forecasting transitions in systems with high dimensional stochastic complex dynamics: A Linear Stability Analysis of the Tangled Nature Model

We propose a new procedure to monitor and forecast the onset of transitions in high dimensional complex systems. We describe our procedure by an application to the Tangled Nature model of evolutionary ecology. The quasi-stable configurations of the full stochastic dynamics are taken as input for a stability analysis by means of the deterministic mean field equations. Numerical analysis of the high dimensional stability matrix allows us to identify unstable directions associated with eigenvalues with positive real part. The overlap of the instantaneous configuration vector of the full stochastic system with the eigenvectors of the unstable directions of the deterministic mean field approximation is found to be a good early-warning of the transitions occurring intermittently.Comment: 4 pages and 4 figures - The new version contains a corrected Figure

Methodological interests and the teaching of research methods in Latin America

This article analyzes a series of historical processes related to the development of shared methodological interests within the community of Latin American social scientist. First, it illustrates how a specific methodological field emerged as part of the institutionalization and professionalization of the social sciences, especially in the US, and how the methodological concerns and debates changed over time. On the other hand, it describes the repercussions of these processes in Latin America, particularly for the emergence of a "scientific" sociology, and how the accumulation of experiences related to the methodological field led to the establishment of specialized institutions in the region, such as the Latin American Network of Social Science Methodology (RedMet). With regard to the methodological interests of Latin American academics, the article focuses on those that have been put forward in the regional congresses of social science methodology (ELMECS) organized biannually by RedMet and, in particular, on the problem of the teaching and learning of research methods, that has been a core concern in all the different countries and institutions. Within this broad interest related to the teaching of methodology, special attention is paid to the results of empirical research conducted on how methods are actually taught in varius PhD programs of different Latin American universities from Argentina, Brazil and Mexico.Documento incorporado en 2018 en el marco del "Programa de becas de experiencia laboral" de la Biblioteca Profesor Guillermo Obiols para estudiantes de Bibliotecología, a partir de un procedimiento técnico de captura de datos desarrollado por el personal del IdIHCS.Facultad de Humanidades y Ciencias de la Educació

Determinants Of Drug Utilisation During Childhood

Paediatric pharmacology is a neglected area in terms of rational use of drugs. Wide differences have been observed in children’s exposure to drugs between and within countries and regions. The aim of the current thesis is to investigate the determinants of drug prescription in paediatrics. Pharmacoepidemiology and the use of administrative databases can be a useful tool for this scope. Data collected in regional and multiregional administrative prescription databases were analysed. Prevalence data by sex and age were calculated by dividing the number of drug users by the total number of male and female residents in each age group. Univariable and multivariable analyses were performed with the aim to identify the determinants of drug prescriptions. The studies showed quantitative and qualitative differences in drug prescription to children and adolescents among Italian regions and within regions. The prescription of a great number of different, redundant, active substances, even among experienced paediatricians, was found. A North-South trend was found in antiasthmatic and antibiotic prevalence, with an important association with average income at the area level. A confirmation of the high prevalence of these drugs and poor qualitative profile was also found. Large heterogeneity was found in psychotropic drug prevalence among different Italian regions. Psychotropic drugs were scantly prescribed and some of the most used drugs were prescribed off-label. The analyses of the prescription of generic antibiotics showed that generic formulations are scantly prescribed by Italian paediatricians, and the lowest prescription rate of generic drugs was found in paediatricians who prescribe more antibiotics. Some quality indicators for antibiotic prescribing were developed at the paediatrician level. The youngest paediatricians and those who were not exposed to educational interventions showed a significantly worse quality of prescribing. The thesis provide some useful data for policy makers in order to improve the rational drug use in children

Testing the homology of metazoan larvae using single cell sequencing data

Members of at least 15 animal phyla have a bi-phasic lifecycle composed of a pelagic larval stage which metamorphoses into a benthic adult. This lifecycle enables larvae to disperse in the ocean to colonise new environments. Although bi-phasic life cycles are widespread across Metazoa, it is unclear if marine larvae were present in the common ancestor or have evolved multiple times as an adaptation to a common selective pressure. Answering this question is fundamental if we are to reconstruct the lifecycle of the last common ancestor of animals. Many marine larvae are at least superficially similar, they are small, swim through beating of ciliated bands and sense the environment with an apical organ structure. Most animals with such larvae belong to the superclade of Lophotrochozoa and this thesis will concentrate on this group. To assess the homology of larvae, authors have compared the early development and expression profile of similar larval organs across phyla and shown that, generally, these are conserved. However, these studies only compared a handful of species and genes and a more thorough approach is needed. In this work I have used single cell sequencing to characterise the cells present in two lophotrochozoan marine larvae (mollusc’s trochophore larva and polyclad flatworms’ Mueller’s larva). I have performed in situ hybridisation and hybridisation chain reaction to identify cells belonging to different structures (including the ciliary bands and apical organ). Subsequently, I have compared the expression of orthologous genes in cell types of the two larvae. I have found that ciliary cells, neurons, muscles and proliferative cells co-express a large number of orthologous genes (>600) of which many are transcription factors (>30). 4 These results hint at a likely homology of lophotrochozoan larvae and set the basis to expand comparative work to more larvae across Bilateria and possibly Metazoa

De objeto a método: notas históricas sobre estatística e pesquisa social

Este artigo analisa o complexo processo histórico, social e cultural que acompanhou as mudan as de sentido do termo “estatística” (de objeto a método): desde o estudo comparativo dos Estados, no século XVIII, a descri o quantitativa da sociedade, no século XIX, ate sua concep o como conjunto de instrumentos conceituais e operacionais para a analise quantitativa de dados a partir do século XX. Neste marco se reconstroem três tradi es intelectuais cujas origens remontam a meados do século XVII – a aritmética politica inglesa, a estatística universitária alem e a teoria matemática das probabilidades francesa – com a finalidade de esclarecer as raízes profundas da teoria estatística moderna no pensamento cientifico europeu e por em evidencia como o entrela amento dessas tradi es, ao longo do tempo, foi redefinindo o sentido da estatística e sua rela o com a pesquisa social empírica.Fil: Piovani, Juan Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Instituto de Investigaciones en Humanidades y Ciencias Sociales; Argentin

Relating high dimensional stochastic complex systems to low-dimensional intermittency

We evaluate the implication and outlook of an unanticipated simplification in the macroscopic behavior of two high-dimensional sto-chastic models: the Replicator Model with Mutations and the Tangled Nature Model (TaNa) of evolutionary ecology. This simplification consists of the apparent display of low-dimensional dynamics in the non-stationary intermittent time evolution of the model on a coarse-grained scale. Evolution on this time scale spans generations of individuals, rather than single reproduction, death or mutation events. While a local one-dimensional map close to a tangent bifurcation can be derived from a mean-field version of the TaNa model, a nonlinear dynamical model consisting of successive tangent bifurcations generates time evolution patterns resembling those of the full TaNa model. To advance the interpretation of this finding, here we consider parallel results on a game-theoretic version of the TaNa model that in discrete time yields a coupled map lattice. This in turn is represented, a la Langevin, by a one-dimensional nonlinear map. Among various kinds of behaviours we obtain intermittent evolution associated with tangent bifurcations. We discuss our results.Comment: arXiv admin note: text overlap with arXiv:1604.0024

Single-cell transcriptomics refuels the exploration of spiralian biology

Spiralians represent the least studied superclade of bilaterian animals, despite exhibiting the widest diversity of organisms. Although spiralians include iconic organisms, such as octopus, earthworms and clams, a lot remains to be discovered regarding their phylogeny and biology. Here, we review recent attempts to apply single-cell transcriptomics, a new pioneering technology enabling the classification of cell types and the characterisation of their gene expression profiles, to several spiralian taxa. We discuss the methodological challenges and requirements for applying this approach to marine organisms and explore the insights that can be brought by such studies, both from a biomedical and evolutionary perspective. For instance, we show that single-cell sequencing might help solve the riddle of the homology of larval forms across spiralians, but also to better characterise and compare the processes of regeneration across taxa. We highlight the capacity of single-cell to investigate the origin of evolutionary novelties, as the mollusc shell or the cephalopod visual system, but also to interrogate the conservation of the molecular fingerprint of cell types at long evolutionary distances. We hope that single-cell sequencing will open a new window in understanding the biology of spiralians, and help renew the interest for these overlooked but captivating organisms

Styles of academic production in the Argentine social sciences: Heterogeneity and heterodoxy

Argentina is an appealing case for analyzing the social science system. In recent years (until 2015) there has been a robust increase in public funding, giving way to the expansion of research, the recruitment of hundreds of new full-time researchers and the consolidation of scholarships for PhD students. All this, in turn, has resulted in a remarkable increase in publications. Although these processes have occurred in the midst of professionalization (which implies higher levels of adherence to international academic standards), recent studies have shown that two contesting models within the social sciences continue to prevail in Argentina: one that conforms to international standards and practices, and another of a more endogenous nature, with its own logic for knowledge production, evaluation and circulation. In order to examine the impact of international standards in the Argentine social sciences, in this paper I analyze the styles of academic production. This implies the study of three closely related dimensions: research processes and models (theoretical foundations, methods, techniques, etc.); writing formats (structure and organization of academic texts); and publication logics (types of publications, profiles of the journals where the articles are published, etc.). The analysis is based on a large sample of publications selected by other researchers in order to carry out a comprehensive review of Argentine literature with regard to six key themes of the social sciences. These publications were also used to produce a dataset with several variables related to the three above-mentioned dimensions. In particular, this paper focuses on the publications grounded in empirical research, and compares qualitative with quantitative research and the various types of publications (journal articles, book chapters and conference papers). The results show that regardless of the recent process of professionalization, “heterodox models” of academic production are still largely pervasive within the Argentine social sciences.Fil: Piovani, Juan Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones en Humanidades y Ciencias Sociales. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación. Instituto de Investigaciones en Humanidades y Ciencias Sociales; Argentin