PP-persistent homology of finite topological spaces

Let $P$ be a finite poset. We will show that for any reasonable $P$-persistent object $X$ in the category of finite topological spaces, there is a $P-$ weighted graph, whose clique complex has the same $P$-persistent homology as $X$

Construction of and efficient sampling from the simplicial configuration model

Simplicial complexes are now a popular alternative to networks when it comes to describing the structure of complex systems, primarily because they encode multi-node interactions explicitly. With this new description comes the need for principled null models that allow for easy comparison with empirical data. We propose a natural candidate, the simplicial configuration model. The core of our contribution is an efficient and uniform Markov chain Monte Carlo sampler for this model. We demonstrate its usefulness in a short case study by investigating the topology of three real systems and their randomized counterparts (using their Betti numbers). For two out of three systems, the model allows us to reject the hypothesis that there is no organization beyond the local scale.Comment: 6 pages, 4 figure

A comprehensive study for the validation of a LC/MS/MS method for the determination of free and total forms of urinary cortisol and its metabolites

Several pathological conditions can be related to the alteration of the urinary levels of cortisol (F) and itsmetabolites. The determination of each of them in the free and free plus conjugated form can provide adeeper insight into the impaired activity of the cortisol metabolism enzymes, thus improving the diag-nosis protocol currently based only on the determination of total amount of urinary cortisol metabolites.In that view, an LC–MS/MS method for the determination of the free and total amount of urinary F, cor-tisone (E), tetrahydrocortisol (THF), allo-tetrahydrocortisol (A-THF) and tetrahydrocortisone (THE) wasthus developed and validated. Deconjugation of glucocorticoids was carried out by enzymatic hydroly-sis. Analytes were extracted by solid phase extraction, separated by liquid chromatography and analyzedvia electro-spray ionization (negative ion mode) triple-quadrupole mass spectrometry in the selectedreaction monitoring mode using a stable isotope-labeled internal standard.Baseline separation for all compounds, in particular the two stereoisomers A-THF and THF, wasobtained. Matrix effects, not reported so far, were observed and minimized for the determination ofurinary free E and THE. Validated range was 0.5–1000 ng/mL for A-THF and THF, 5–800 ng/mL for E andTHE and 1–1000 ng/mL for F, with R2values greater than 0.9981. The LOD and LOQ of the describedmethod ranged from 0.1 to 3.0 ng/mL, while the extraction recoveries resulted close to 100% for all theglucocorticoids determined. Precision and accuracy were well within ±10%. As suggested by the resultsobtained in the preliminary study on polycystic ovary syndrome (PCOS) urine samples, the method canbe used to support clinical diagnosis of pathologies related to cortisol metabolism. In fact, levels of freeand total glucocorticoids in control subjects were in agreement with previously reported data, as well asfree and total A-THF/THF ratio in PCOS patients. Conversely, in the latter free F/E and A-THF + THF/THEratios were lower than in control subjects (P < 0.01), suggesting a possible alteration of 11-HSD1 and11-HSD2 activity, to be further investigated

P-persistent homology of finite topological spaces

Let P be a finite poset. We will show that for any reasonable P-persistent object X in the category of finite topological spaces, there is a P− weighted graph, whose clique complex has the same P-persistent homology as X

the shape of collaborations

Abstract The structure of scientific collaborations has been the object of intense study both for its importance for innovation and scientific advancement, and as a model system for social group coordination and formation thanks to the availability of authorship data. Over the last years, complex networks approach to this problem have yielded important insights and shaped our understanding of scientific communities. In this paper we propose to complement the picture provided by network tools with that coming from using simplicial descriptions of publications and the corresponding topological methods. We show that it is natural to extend the concept of triadic closure to simplicial complexes and show the presence of strong simplicial closure. Focusing on the differences between scientific fields, we find that, while categories are characterized by different collaboration size distributions, the distributions of how many collaborations to which an author is able to participate is conserved across fields pointing to underlying attentional and temporal constraints. We then show that homological cycles, that can intuitively be thought as hole in the network fabric, are an important part of the underlying community linking structure

Persistent Homology analysis of Phase Transitions

Persistent homology analysis, a recently developed computational method in algebraic topology, is applied to the study of the phase transitions undergone by the so-called XY-mean field model and by the phi^4 lattice model, respectively. For both models the relationship between phase transitions and the topological properties of certain submanifolds of configuration space are exactly known. It turns out that these a-priori known facts are clearly retrieved by persistent homology analysis of dynamically sampled submanifolds of configuration space.Comment: 10 pages; 10 figure

Clauser-Horne-Shimony-Holt Bell inequality test in an optomechanical device

We propose here a scheme, based on the measurement of quadrature phase coherence, aimed at testing the Clauser-Horne-Shimony-Holt Bell inequality in an optomechanical setting. Our setup is constituted by two optical cavities dispersively coupled to a common mechanical resonator. We show that it is possible to generate EPR-like correlations between the quadratures of the output fields of the two cavities, and, depending on the system parameters, to observe the violation of the Clauser-Horne-Shimony-Holt inequality.Comment: 13 pages and 5 figures (typo fixed

Homological scaffold via minimal homology bases

The homological scaffold leverages persistent homology to construct a topologically sound summary of a weighted network. However, its crucial dependency on the choice of representative cycles hinders the ability to trace back global features onto individual network components, unless one provides a principled way to make such a choice. In this paper, we apply recent advances in the computation of minimal homology bases to introduce a quasi-canonical version of the scaffold, called minimal, and employ it to analyze data both real and in silico. At the same time, we verify that, statistically, the standard scaffold is a good proxy of the minimal one for sufficiently complex networks

The addition of simvastatin administration to cold storage solution of explanted whole liver grafts for facing ischemia/reperfusion injury in an area with a low rate of deceased donation: a monocentric randomized controlled double-blinded phase 2 study.

BACKGROUND: Liver transplantation is the best treatment for end-stage liver disease. The interruption of the blood supply to the donor liver during cold storage damages the liver, affecting how well the liver will function after transplant. The drug Simvastatin may help to protect donor livers against this damage and improve outcomes for transplant recipients. The aim of this study is to evaluate the benefits of treating the donor liver with Simvastatin compared with the standard transplant procedure. PATIENT AND METHODS: We propose a prospective, double-blinded, randomized phase 2 study of 2 parallel groups of eligible adult patients. We will compare 3-month, 6-month, and 12-month graft survival after LT, in order to identify a significant relation between the two homogenous groups of LT patients. The two groups only differ by the Simvastatin or placebo administration regimen while following the same procedure, with identical surgical instruments, and medical and nursing skilled staff. To reach these goals, we determined that we needed to recruit 106 patients. This sample size achieves 90% power to detect a difference of 14.6% between the two groups survival using a one-sided binomial test. DISCUSSION: This trial is designed to confirm the effectiveness of Simvastatin to protect healthy and steatotic livers undergoing cold storage and warm reperfusion before transplantation and to evaluate if the addition of Simvastatin translates into improved graft outcomes. TRIAL REGISTRATION: ISRCTN27083228

Kinanthropometry and Anatomical Body Composition of Elite Soccer Players in Argentina: The FUTREF Project

Introduction: Anthropometric references for sports enable researchers and sports nutrition professionals to accurately assess body composition in an economical and efficient manner. The objective of this study was to provide an extensive anthropometric profile of elite soccer players divided by playing position. Seven hundred fifty-two players (age 24.0 ± 4.4 years) from 18 different Argentine teams were involved in the FUTREF project and measured according to the protocol defined by the International Society for the Advancement of Kinanthropometry (ISAK). Methods: Raw anthropometric parameters were reported and used to calculate somatotype and body mass components according to molecular (two-components) and anatomical (five-components) models. Results: Statistically significant differences (p&gt;0.01) were identified for anthropometric parameters among different playing positions and between players selected and not selected for the senior national team. The 5th, 25th, 50th, 75th, and 95th percentiles for the muscle-to-bone ratio were provided. Furthermore, the use of different equations showed different outputs in predicting body composition. Conclusion: This study provides anthropometric reference data for evaluating body composition in elite soccer players.Las referencias antropométricas para el deporte permiten a los investigadores y profesionales de la nutrición deportiva evaluar con precisión la composición corporal de una manera económica y eficiente. El objetivo de este estudio fue proporcionar un perfil antropométrico extenso de jugadores de fútbol de élite dividido por posición de juego. En el proyecto FUTREF participaron setecientos cincuenta y dos jugadores (edad 24,0 ± 4,4 años) de 18 equipos argentinos diferentes, medidos según el protocolo definido por la Sociedad Internacional para el Avance de la Cineantropometría (ISAK). Métodos: Se informaron parámetros antropométricos brutos y se utilizaron para calcular los componentes del somatotipo y la masa corporal según modelos moleculares (dos componentes) y anatómicos (cinco componentes). Resultados: Se identificaron diferencias estadísticamente significativas (p&gt;0,01) para los parámetros antropométricos entre las diferentes posiciones de juego y entre jugadores seleccionados y no seleccionados para la selección absoluta. Se proporcionaron los percentiles 5, 25, 50, 75 y 95 para la relación músculo-hueso. Además, el uso de diferentes ecuaciones mostró diferentes resultados en la predicción de la composición corporal. Conclusión: Este estudio proporciona datos antropométricos de referencia para evaluar la composición corporal en jugadores de fútbol de élite