In recent years, the question of the reliability of Machine Learning (ML) methods has acquired significant importance, and the analysis of the associated uncertainties has motivated a growing amount of research. However, most of these studies have applied standard error analysis to ML models—and in particular Deep Neural Network (DNN) models—which represent a rather significant departure from standard scientific modelling. It is therefore necessary to integrate the standard error analysis with a deeper epistemological analysis of the possible differences between DNN models and standard scientific modelling and the possible implications of these differences in the assessment of reliability. This article offers several contributions. First, it emphasises the ubiquitous role of model assumptions (both in ML and traditional science) against the illusion of theory-free science. Secondly, model assumptions are analysed from the point of view of their (epistemic) complexity, which is shown to be language-independent. It is argued that the high epistemic complexity of DNN models hinders the estimate of their reliability and also their prospect of long term progress. Some potential ways forward are suggested. Thirdly, this article identifies the close relation between a model’s epistemic complexity and its interpretability, as introduced in the context of responsible AI. This clarifies in which sense—and to what extent—the lack of understanding of a model (black-box problem) impacts its interpretability in a way that is independent of individual skills. It also clarifies how interpretability is a precondition for a plausible assessment of the reliability of any model, which cannot be based on statistical analysis alone. This article focuses on the comparison between traditional scientific models and DNN models. However, Random Forest (RF) and Logistic Regression (LR) models are also briefly considered.

Está demostrado en diversos estudios que los avances en el diagnóstico microbiológico reduce el tiempo de entrega de resultados y posee un impacto clínico evidente. Hoy en día, las técnicas basadas en amplificación de ácidos nucleicos nos permiten hacer diagnóstico directamente de la muestra y sumar la posibilidad de detectar más de un agente. Esto impacta tanto en el control de la MMR como en el inicio de una terapéutica apropiada. La implementación de un sistema de PCR múltiple rápido para neumonía puede ser útil en áreas críticas donde son frecuentes las infecciones respiratorias agudas (IRA) y el tiempo es un condicionante del éxito terapéutico. El objetivo de nuestro proyecto fue evaluar la implementación del diagnóstico sindrómico rápido por PCR múltiple para neumonía en el manejo del tratamiento de IRA en una Unidad de Cuidados Intensivos. La conducta terapéutica fue la variable relevante. Este nuevo diagnóstico nos proporcionó una herramienta ágil, con un tiempo de respuesta de 3 a 4 horas. La ausencia o presencia de genes de resistencia y el microorganismo identificado, fue lo que condujo a la conducta terapéutica acertada en el 75% de los casos. Constituyó una herramienta importante para el control de la multirresistencia bacteriana y aumentó la oportunidad de éxito terapéutico.

By employing a twisted mass term, we compare recent results from lattice calculations of Nf = 2 dynamical Wilson fermions with Wilson Chiral Perturbation Theory (WChPT). The final goal is to determine some combinations of Gasser-Leutwyler Low Energy Constants (LECs). A wide set of data with different lattice spacings (a ∼ 0.2 − 0.12 fm), different gauge actions (Wilson plaquette, DBW2) and different quark masses (down to the lowest pion mass allowed by lattice artifacts and including negative quark masses) provide a strong check of the applicability of WChPT in this regime and the scaling behaviours in the continuum limit.

It is mostly agreed that Popper's criterion of falsifiability fails to provide a useful demarcation between science and pseudo-science, because ad-hoc assumptions are always able to save any theory that conflicts with the empirical data (a.k.a. the Duhem-Quine problem), and a characterization of ad-hoc assumptions is lacking. Moreover, adding some testable predictions is not very difficult. It should be emphasized that these problems do not simply make Popper's demarcation approximate (if it were so, all our problems would be solved!), they make it totally useless. More in general, no philosophical criterion of demarcation is presently able to rule out even some of the most blatant cases of pseudo-science, not even approximatively (in any well defined sense of approximation). This is in sharp contrast with our firm belief that some theories are clearly not scientific. Where does this belief come from? In this paper I argue that it is necessary and possible to recognize the notion of syntactic simplicity that is able to tell the difference between empirically equivalent scientific and non-scientific theories, with a confidence that is adequate to many important practical purposes, and it fully agrees with the judgments generally held in the scientific community.

I argue that the key to understand many fundamental issues in philosophy of science lies in understanding the subtle relation between the non-empirical cognitive values used in science (often implicitly, but crucially) and the constraints imposed by measurability. In fact, although we are not able to fix the interpretation of a scientific theory through its formulation, I show that measurability puts constraints that can at least exclude some implausible interpretations. This turns out to be enough to define at least one cognitive value (conciseness) that is able to penalize, without damages, precisely those bad features that deceive purely empirical assessments. This leads to the formulation of a simple model of scientific progress, that is based only on empirical accuracy and conciseness. The model is confronted here with many possible objections and with challenging cases of real progress. Although I cannot exclude that the model might be incomplete, it includes all the cases of genuine progress examined here, and no spurious one. In this model, I stress the role of the state of the art, which is the collection of all the theories that are the only legitimate source of scientific predictions. Progress is a global upgrade of the state of the art.

We propose an efficient method to compute the so-called residual phase that appears when performing Monte Carlo calculations on a Lefschetz thimble. The method is stochastic and its cost scales linearly with the physical volume, linearly with the number of stochastic estimators and quadratically with the length of the extra dimension along the gradient flow. This is a drastic improvement over previous estimates of the cost of computing the residual phase. We also report on basic tests of correctness and scaling of the code.

We review the status of an ongoing long-term lattice investigation of the spectrum and structure of tetraquark candidates. We focus on the light scalar meson a(0)(980). First steps regarding the study of a possibly existing cc (c) over bar(c) over bar tetraquark are also outlined.

We present a lattice QCD calculation of the up, down, strange and charm quark masses performed using the gauge configurations produced by the European Twisted Mass Collaboration with Nf=2+1+1 dynamical quarks, which include in the sea, besides two light mass degenerate quarks, also the strange and charm quarks with masses close to their physical values. The simulations are based on a unitary setup for the two light quarks and on a mixed action approach for the strange and charm quarks. The analysis uses data at three values of the lattice spacing and pion masses in the range 210–450 MeV, allowing for accurate continuum limit and controlled chiral extrapolation. The quark mass renormalization is carried out non-perturbatively using the RI′-MOM method. The results for the quark masses converted to the MS¯ scheme are: mud(2 GeV)=3.70(17) MeV, ms(2 GeV)=99.6(4.3) MeV and mc(mc)=1.348(46) GeV. We obtain also the quark mass ratios ms/mud=26.66(32) and mc/ms=11.62(16). By studying the mass splitting between the neutral and charged kaons and using available lattice results for the electromagnetic contributions, we evaluate mu/md=0.470(56), leading to mu=2.36(24) MeV and md=5.03(26) MeV.

We present an overview of recent developments in the tmLQCD software suite. We summarise the features of the code, including actions and operators implemented. In particular, we discuss the optimisation efforts for modern architectures using the Blue Gene/Q system as an example.

In these proceedings, we summarize the Lefschetz thimble approach to the sign problem of Quantum Field Theories. In particular, we review its motivations, and we summarize the results of the application of two different algorithms to two test models.

We present lattice results for the a_0(980) state using a variational approach with a variety of creation operators: quark-antiquark, mesonic molecule, diquark-antidiquark as well as two-meson type. Focus is put on recent technical advances, in particular the computation of singly disconnected diagrams.

We study the light scalar mesons a_0(980) and kappa using N_f = 2+1+1 flavor lattice QCD. In order to probe the internal structure of these scalar mesons, and in particular to identify, whether a sizeable tetraquark component is present, we use a large set of operators, including diquark-antidiquark, mesonic molecule and two-meson operators. The inclusion of disconnected diagrams, which are technically rather challenging, but which would allow us to extend our work to e.g. the f_0(980) meson, is introduced and discussed.

In this contribution, a first look at simulations using maximally twisted mass Wilson fermions at the physical point is presented. A lattice action including clover and twisted mass terms is presented and the Monte Carlo histories of one run with two mass-degenerate flavours at a single lattice spacing are shown. Measurements from the light and heavy-light pseudoscalar sectors are compared to previous $N_f = 2$ results and their phenomenological values. Finally, the strategy for extending simulations to $N_f = 2 + 1 + 1$ is outlined.

We study light scalar mesons with particular focus on the a_0(980) using lattice QCD with 2+1+1 dynamical quark flavors. To investigate the structure of these scalar mesons and to identify, whether a sizeable tetraquark component is present, we use a large set of operators, including diquark-antidiquark, mesonic molecule and two-meson operators. We find that the low-lying states overlap essentially exclusively with two-meson states. This indicates that in the channels investigated no tightly bound four-quark states of either molecular or diquark-antidiquark type exist.

Introduccion: La gonorrea es una Infeccion de Transmision sexual (ITS), causada por Neisseria gonorrhoeae (Ng), microorganismo capaz de desarrollar resistencia (R) a todos los antimicrobianos utilizados para su tratamiento: penicilinas (PEN), tetraciclinas (TET) y ciprofloxacina (CIP). En la actualidad el tratamiento incluye las cefalosporinas de 3ra. generacion (C3G): ceftriaxona (CRO) y cefixima (CFM). La OMS ha emitido un alerta epidemiologico sobre cepas de Ng multirresistentes (MR). La perdida de las cefalosporinas de 3° generacion para el tratamiento de la gonorrea no complicada seria un problema de Salud Publica. Es de fundamental importancia la vigilancia epidemiologica para guiar las decisiones terapeuticas y contener la diseminacion de la resistencia. Objetivos: Evaluar la susceptibilidad a ciprofloxacina y ceftriaxona para orientar el tratamiento empirico inicial en pacientes que concurrieron al Laboratorio de Microbiologia, con diagnostico de ITS. Lugar de aplicacion y diseno: Hospital de Agudos J.M Penna, Ciudad Autonoma de Buenos Aires, Argentina. Estudio retrospectivo, descriptivo. Materiales y metodos: Se analizaron los aislamientos de Neisseria gonorrhoeae entre 01/01/2012 y 15/09/2013, la identificacion de Neisseria gonorrhoeae se realizo por pruebas bioquimicas y sistema Vitek 2C (BioMerieux®) y en el antibiograma se probaron: penicilina, tetraciclina, ciprofloxaciona, ceftriaxona y cefixima. Resultados: Se recuperaron 26 cepas de Neisseria gonorrhoeae, provenientes de exudados uretrales masculinos (23), exudados cervicales (2) y liquido de cavidad peritoneal (1), en una paciente con diagnostico clinico de enfermedad pelvica inflamatoria. Del total de aislamientos, 13/26 (50%) presentaron resistencia a penicilina, 4/26 (15%) fueron productoras de betalactamas, 15/26 (58%) presentaron resistencia a tetraciclina y 17/26 (65%) resistencia a ciprofloxacina. Todas fueron sensibles a ceftriaxona y cefixima. Se considero multirresistencia a la resistencia de 3 o mas antibioticos, siendo el 42% (11/26) de nuestros aislamientos multirresistente. Conclusiones: Los altos niveles de resistencia hallados sugieren que penicilina, tetraciclina y ciprofloxacina no deberian emplearse en la terapeutica inicial. Las cefalosporinas de 3° generacion mantienen aun su efectividad y serian de primera eleccion. Creemos que es importante estudiar a todos los pacientes sintomaticos y realizar cultivo de vigilancia a la poblacion asintomatica en riesgo en forma sistematica para: controlar la transmision de la infeccion gonococica, detectar la emergencia de las cepas multirresistentes y alertar en forma temprana sobre cambios en el tratamiento empirico de la gonorrea no complicada.

Introducción: La gonorrea es una Infección de Transmisión sexual (ITS), causada por Neisseria gonorrhoeae (Ng), microorganismo capaz de desarrollar resistencia (R) a todos los antimicrobianos utilizados para su tratamiento: penicilinas (PEN), tetraciclinas (TET) y ciprofloxacina (CIP). En la actualidad el tratamiento incluye las cefalosporinas de 3ra. generación (C3G): ceftriaxona (CRO) y cefixima (CFM). La OMS ha emitido un alerta epidemiológico sobre cepas de Ng multirresistentes (MR). La pérdida de las cefalosporinas de 3° generación para el tratamiento de la gonorrea no complicada sería un problema de Salud Pública. Es de fundamental importancia la vigilancia epidemiológica para guiar las decisiones terapéuticas y contener la diseminación de la resistencia. Objetivos: Evaluar la susceptibilidad a ciprofloxacina y ceftriaxona para orientar el tratamiento empírico inicial en pacientes que concurrieron al Laboratorio de Microbiología, con diagnóstico de ITS. Lugar de aplicación y diseño: Hospital de Agudos J.M Penna, Ciudad Autónoma de Buenos Aires, Argentina. Estudio retrospectivo, descriptivo. Materiales y métodos: Se analizaron los aislamientos de Neisseria gonorrhoeae entre 01/01/2012 y 15/09/2013, la identificación de Neisseria gonorrhoeae se realizó por pruebas bioquímicas y sistema Vitek 2C (BioMerieux®) y en el antibiograma se probaron: penicilina, tetraciclina, ciprofloxaciona, ceftriaxona y cefixima. Resultados: Se recuperaron 26 cepas de Neisseria gonorrhoeae, provenientes de exudados uretrales masculinos (23), exudados cervicales (2) y líquido de cavidad peritoneal (1), en una paciente con diagnóstico clínico de enfermedad pélvica inflamatoria. Del total de aislamientos, 13/26 (50%) presentaron resistencia a penicilina, 4/26 (15%) fueron productoras de betalactamas, 15/26 (58%) presentaron resistencia a tetraciclina y 17/26 (65%) resistencia a ciprofloxacina. Todas fueron sensibles a ceftriaxona y cefixima. Se consideró multirresistencia a la resistencia de 3 o más antibióticos, siendo el 42% (11/26) de nuestros aislamientos multirresistente. Conclusiones: Los altos niveles de resistencia hallados sugieren que penicilina, tetraciclina y ciprofloxacina no deberían emplearse en la terapéutica inicial. Las cefalosporinas de 3° generación mantienen aún su efectividad y serían de primera elección. Creemos que es importante estudiar a todos los pacientes sintomáticos y realizar cultivo de vigilancia a la población asintomática en riesgo en forma sistemática para: controlar la transmisión de la infección gonocócica, detectar la emergencia de las cepas multirresistentes y alertar en forma temprana sobre cambios en el tratamiento empírico de la gonorrea no complicada.

Simple assumptions represent a decisive reason to prefer one theory to another in everyday scientific praxis. But this praxis has little philosophical justification, since there exist many notions of simplicity, and those that can be defined precisely strongly depend on the language in which the theory is formulated. The language dependence is a natural feature—to some extent—but it is also believed to be a fatal problem, because, according to a common general argument, the simplicity of a theory is always trivial in a suitably chosen language. But, this trivialization argument is typically either applied to toy-models of scientific theories or applied with little regard for the empirical content of the theory. This paper shows that the trivialization argument fails, when one considers realistic theories and requires their empirical content to be preserved . In fact, the concepts that enable a very simple formulation, are not necessarily measurable, in general. Moreover, the inspection of a theory describing a chaotic billiard shows that precisely those concepts that naturally make the theory extremely simple are provably not measurable. This suggests that—whenever a theory possesses sufficiently complex consequences—the constraint of measurability prevents too simple formulations in any language. This explains why the scientists often regard their assessments of simplicity as largely unambiguous. In order to reveal a cultural bias in the scientists’ assessment, one should explicitly identify different characterizations of simplicity of the assumptions that lead to different theory selections. General arguments are not sufficient.

We propose a new algorithm based on the Metropolis sampling method to perform Monte Carlo integration for path integrals in the recently proposed formulation of quantum field theories on the Lefschetz thimble. The algorithm is based on a mapping between the curved manifold defined by the Lefschetz thimble of the full action and the flat manifold associated with the corresponding quadratic action. We discuss an explicit method to calculate the residual phase due to the curvature of the Lefschetz thimble. Finally, we apply this new algorithm to a simple one-plaquette model where our results are in perfect agreement with the analytic integration. We also show that for this system the residual phase does not represent a sign problem.

We present the first practical Monte Carlo calculations of the recently proposed Lefschetz thimble formulation of quantum field theories. Our results provide strong evidence that the numerical sign problem that afflicts Monte Carlo calculations of models with complex actions can be softened significantly by changing the domain of integration to the Lefschetz thimble or approximations thereof. We study the interacting complex scalar field theory (relativistic Bose gas) in lattices of size up to 8^4 using a computationally inexpensive approximation of the Lefschetz thimble. Our results are in excellent agreement with known results. We show that - at least in the case of the relativistic Bose gas - the thimble can be systematically approached and the remaining residual phase leads to a much more tractable sign problem (if at all) than the original formulation. This is especially encouraging in view of the wide applicability - in principle - of our method to quantum field theories with a sign problem. We believe that this opens up new possibilities for accurate Monte Carlo calculations in strongly interacting systems of sizes much larger that previously possible.