Causal deep learning models for studying the Earth system

Earth is a complex non-linear dynamical system. Despite decades of research and considerable scientific and methodological progress, many processes and relations between Earth system variables remain poorly understood. Current approaches for studying relations in the Earth system rely either on numerical simulations or statistical approaches. However, there are several inherent limitations to existing approaches, including high computational costs, uncertainties in numerical models, strong assumptions about linearity or locality, and the fallacy of correlation and causality. Here, we propose a novel methodology combining deep learning (DL) and principles of causality research in an attempt to overcome these limitations. On the one hand, we employ the recent idea of training and analyzing DL models to gain new scientific insights into relations between input and target variables. On the other hand, we use the fact that a statistical model learns the causal effect of an input variable on a target variable if suitable additional input variables are included. As an illustrative example, we apply the methodology to study soil-moisture–precipitation coupling in ERA5 climate reanalysis data across Europe. We demonstrate that, harnessing the great power and flexibility of DL models, the proposed methodology may yield new scientific insights into complex non-linear and non-local coupling mechanisms in the Earth system.</p

A transitividade de verbos de elocução à luz do Funcionalismo.

Esta dissertação aborda o fenômeno da transitividade em notas sociais, com vistas a entender melhor o comportamento de verbos de elocução comumente usados nesses textos. Para dar conta do estudo que pretendemos empreender, partimos das proposições tradicionais no que tange à transitividade, também consideramos as abordagens descritivas e elegemos como referencial teórico a perspectiva funcionalista da linguagem, dentro da qual encontra-se uma concepção de transitividade formulada por Hopper e Thompson (1980). Ao relacionar as referidas vertentes teóricas, percebemos a necessidade de ampliar, ou até atualizar, a maneira como a transitividade é concebida. Diante disso, a empreitada assumida por nós se justifica, pois propomos um estudo da transitividade para além do olhar normativo e objetivamos compreender melhor o funcionamento dos verbos de elocução e a transitividade das orações que os abrigam em um contexto de uso. O corpus elegido para este estudo foram as notas sociais publicadas na seção Planeta Pop, do caderno AT2, do jornal A Tribuna, que são pequenos textos noticiando alguma informação sobre a vida de pessoas famosas no meio artístico e de nacionalidade estrangeira, tendo os verbos de elocução como um componente essencial. A metodologia adotada foi a de observar, descrever e analisar o fenômeno eleito para nossa investigação. Dessa forma, após reunirmos os dados, visualizamos as ocorrências dos verbos de elocução, buscando descrever o ambiente em que se inserem para, então, aferirmos a transitividade das orações e demonstrarmos, por meio de alguns exemplos, a dinâmica de uso desses verbos e das orações em relação à transitividade. A pesquisa revelou um alto grau de transitividade nas cláusulas que formam as notas sociais e que os verbos de elocução não revelam um objeto sintático paciente, ou seja, que sofre a transferência da ação verbal, o que justifica o fato de, no que se refere aos Parâmetros de Transitividade de Hopper e Thompson (1980), não identificarmos, em nenhuma das orações analisadas, o afetamento e a individuação do objeto

X ray absorption spectroscopy of TiO2 nanoparticles in water using a holey membrane based flow cell

Many applications of TiO2 nanoparticles, such as photocatalytic water splitting or water remediation, occur in aqueous environment. However, the impact of solvation on TiO2 electronic structure remains unclear because only few experimental methods are currently available to probe nanoparticle water interface. Soft X ray absorption spectroscopy has been extensively used to characterize the electronic structure of TiO2 materials, but so far only in vacuum conditions. Here, oxygen K edge and titanium L edge X ray absorption spectroscopy characterization of TiO2 nanoparticles measured directly in aqueous dispersion is presented. For this purpose, a new method to probe nanomaterials in liquid using a holey membrane based flow cell is introduced. With this approach, the X ray transmission of the membrane is increased, especially in the water window, compared to solid membrane

Optimal control theory for unitary transformations

The dynamics of a quantum system driven by an external field is well described by a unitary transformation generated by a time dependent Hamiltonian. The inverse problem of finding the field that generates a specific unitary transformation is the subject of study. The unitary transformation which can represent an algorithm in a quantum computation is imposed on a subset of quantum states embedded in a larger Hilbert space. Optimal control theory (OCT) is used to solve the inversion problem irrespective of the initial input state. A unified formalism, based on the Krotov method is developed leading to a new scheme. The schemes are compared for the inversion of a two-qubit Fourier transform using as registers the vibrational levels of the $X^1\Sigma^+_g$ electronic state of Na$_2$. Raman-like transitions through the $A^1\Sigma^+_u$ electronic state induce the transitions. Light fields are found that are able to implement the Fourier transform within a picosecond time scale. Such fields can be obtained by pulse-shaping techniques of a femtosecond pulse. Out of the schemes studied the square modulus scheme converges fastest. A study of the implementation of the $Q$ qubit Fourier transform in the Na$_2$ molecule was carried out for up to 5 qubits. The classical computation effort required to obtain the algorithm with a given fidelity is estimated to scale exponentially with the number of levels. The observed moderate scaling of the pulse intensity with the number of qubits in the transformation is rationalized.Comment: 32 pages, 6 figure

Characterisation, expression and ontogeny of interleukin-6 and its receptors in zebrafish (Danio rerio)

10 páginas, 8 figuras, 2 tablasInterleukin-6 (IL-6) is one of the most pleiotropic cytokines due to its importance in both innate and adaptive immune responses and other physiological processes. In this study, we identified the zebrafish (Danio rerio) IL-6 homologue by investigating the synteny between the human (Homo sapiens), the fugu (Takifugu rubripes) and the zebrafish genome. Although zebrafish IL-6 showed a low sequence homology with other IL-6 sequences in other species, it presented a high structural similarity to human IL-6. We also analysed IL-6 expression in several different tissues, along with analysis of the expression of the genes that form the IL-6 receptor complex, IL-6R and gp130. After treatment with bacterial or viral stimuli, zebrafish IL-6 expression was modulated in a manner similar to that of other proinflammatory molecules, such as IL-1β and TNF-α. The expression of IL-6, IL-6R and gp130 was also studied during the ontogeny of zebrafish larvae using quantitative PCR and in situ hybridisation. Our results indicated that the transcripts were detected very early, increased during the first week of life and were predominantly expressed in the head, epidermis and neuromasts of the anterior and posterior lateral line system, suggesting their involvement in the normal development of these tissues.We want to thank the funding from the project CSD2007-00002 “Aquagenomics” of the program Consolider-Ingenio 2010 from the Spanish Ministerio de Ciencia e Innovación. M. Varela gratefully acknowledges the JAE Program, co financed by CSIC and European Social Funds, for a predoctoral grant.Peer reviewe

High brightness inductively coupled plasma source for high current focused ion beam applications

A high brightnessplasmaion source has been developed to address focused ion beam(FIB) applications not satisfied by the liquid metal ion source (LMIS) based FIB. The plasmaFIB described here is capable of satisfying applications requiring high mill rates (>100μm³/s) with non-gallium ions and has demonstrated imaging capabilities with sub- 100-nm resolution. The virtual source size, angular intensity, mass spectra, and energy spread of the source have been determined with argon and xenon. This magnetically enhanced, inductively coupled plasmasource has exhibited a reduced brightness(βr) of 5.4×10³Am⁻²sr⁻¹V⁻¹, with a full width half maximum axial energy spread (ΔE) of 10eV when operated with argon. With xenon, βr=9.1×10³Am⁻²sr⁻¹V⁻¹ and ΔE=7eV. With these source parameters, an optical column with sufficient demagnification is capable of forming a sub-25-nm spot size at 30keV and 1pA. The angular intensity of this source is nominally three orders of magnitude greater than a LMIS making the source more amenable to creating high current focused beams, in the regime where spherical aberration dominates the LMIS-FIB. The source has been operated on a two lens ion column and has demonstrated a current density that exceeds that of the LMIS-FIB for current greater than 50nA. Source lifetime and current stability are excellent with inert and reactive gases. Additionally, it should be possible to improve both the brightness and energy spread of this source, such that the (βr/ΔE₂) figure-of-merit could be within an order of magnitude of a LMIS

Helping education undergraduates to use appropriate criteria for evaluating accounts of motivation

The aim of the study was to compare students in a control group with those in a treatment group with respect to evaluative comments on psychological accounts of motivation. The treatment group systematically scrutinized the nature and interpretation of evidence that supported different accounts, and the assumptions, logic, coherence and clarity of accounts. Content analysis of 74 scripts (using three categories) showed that the control group students made more assertions than either evidential or evaluative points, whereas the treatment group used evaluative statements as often as they used assertion. The findings provide support for privileging activities that develop understanding of how knowledge might be contested, and suggest a need for further research on pedagogies to serve this end. The idea is considered that such understanding has a pivotal role in the development of critical thinking

Identifying chemokines as therapeutic targets in renal disease: Lessons from antagonist studies and knockout mice

Chemokines, in concert with cytokines and adhesion molecules, play multiple roles in local and systemic immune responses. In the kidney, the temporal and spatial expression of chemokines correlates with local renal damage and accumulation of chemokine receptor-bearing leukocytes. Chemokines play important roles in leukocyte trafficking and blocking chemokines can effectively reduce renal leukocyte recruitment and subsequent renal damage. However, recent data indicate that blocking chemokine or chemokine receptor activity in renal disease may also exacerbate renal inflammation under certain conditions. An increasing amount of data indicates additional roles of chemokines in the regulation of innate and adaptive immune responses, which may adversively affect the outcome of interventional studies. This review summarizes available in vivo studies on the blockade of chemokines and chemokine receptors in kidney diseases, with a special focus on the therapeutic potential of anti-chemokine strategies, including potential side effects, in renal disease. Copyright (C) 2004 S. Karger AG, Basel