Group-Wise Principal Component Analysis for Exploratory Intrusion Detection

Intrusion detection is a relevant layer of cybersecurity to prevent hacking and illegal activities from happening on the assets of corporations. Anomaly-based Intrusion Detection Systems perform an unsupervised analysis on data collected from the network and end systems, in order to identify singular events. While this approach may produce many false alarms, it is also capable of identifying new (zeroday) security threats. In this context, the use of multivariate approaches such as Principal Component Analysis (PCA) provided promising results in the past. PCA can be used in exploratory mode or in learning mode. Here, we propose an exploratory intrusion detection that replaces PCA with Group-wise PCA (GPCA), a recently proposed data analysis technique with additional exploratory characteristics. A main advantage of GPCA over PCA is that the former yields simple models, easy to understand by security professionals not trained in multivariate tools. Besides, the workflow in the intrusion detection with GPCA is more coherent with dominant strategies in intrusion detection. We illustrate the application of GPCA in two case studies.This work was supported in part by the Spanish Government-MINECO (Ministerio de Economía y Competitividad), using the Fondo Europeo de Desarrollo Regional (FEDER), under Projects TIN2014-60346-R and Project TIN2017-83494-R

Discussing the physical meaning of the absorption feature at 2.1 keV in 4U 1538–52

High resolution X-ray spectroscopy is a powerful tool for studying the nature of the matter surrounding the neutron star in X-ray binaries and its interaction between the stellar wind and the compact object. In particular, absorption features in their spectra could reveal the presence of atmospheres of the neutron star or their magnetic field strength. Here we present an investigation of the absorption feature at 2.1 keV in the X-ray spectrum of the high mass X-ray binary 4U 1538–52 based on our previous analysis of the XMM-Newton data. We study various possible origins and discuss the different physical scenarios in order to explain this feature. A likely interpretation is that the feature is associated with atomic transitions in an O/Ne neutron star atmosphere or of hydrogen and helium like Fe or Si ions formed in the stellar wind of the donor.This work was supported by the Spanish Ministry of Education and Science “De INTEGRAL a IXO: binarias de rayos X y estrellas activas”, project number AYA2010-15431, partially by GV2014/088 and MIF/14G04. JJRR acknowledges the support by the Spanish Ministerio de Educación y Ciencia under grant PR2009-0455 and by the Vicerectorat d’Investigació, Desenvolupament i Innovació de la Universitat d’Alacant under grant GRE12-35

Orbital phase-resolved spectroscopy of 4U 1538−52 with MAXI

Context. 4U 1538−52, an absorbed high mass X-ray binary with an orbital period of ~3.73 days, shows moderate orbital intensity modulations with a low level of counts during the eclipse. Several models have been proposed to explain the accretion at different orbital phases by a spherically symmetric stellar wind from the companion. Aims. The aim of this work is to study both the light curve and orbital phase spectroscopy of this source in the long term. In particular, we study the folded light curve and the changes in the spectral parameters with orbital phase to analyse the stellar wind of QV Nor, the mass donor of this binary system. Methods. We used all the observations made from the Gas Slit Camera on board MAXI of 4U 1538−52 covering many orbits continuously. We obtained the good interval times for all orbital phase ranges, which were the input for extracting our data. We estimated the orbital period of the system and then folded the light curves, and we fitted the X-ray spectra with the same model for every orbital phase spectrum. We also extracted the averaged spectrum of all the MAXI data available. Results. The MAXI spectra in the 2–20 keV energy range were fitted with an absorbed Comptonisation of cool photons on hot electrons. We found a strong orbital dependence of the absorption column density but neither the fluorescence iron emission line nor low energy excess were needed to fit the MAXI spectra. The variation in the spectral parameters over the binary orbit were used to examine the mode of accretion onto the neutron star in 4U 1538−52. We deduce a best value of Ṁ/v∞ = 0.65 × 10-9M⊙ yr-1/ (km s-1) for QV Nor.Part of this work was supported by the Spanish Ministry of Economy and Competitiveness project numbers ESP2013-48637-C2-2P, and ESP2014-53672-C3-3-P, by the Vicerectorat d’Investigació, Desenvolupament i Innovació de la Universitat d’Alacant project number GRE12-35, and by the Generalitat Valenciana project number GV2014/088. This research made use of MAXI data provided by RIKEN, JAXA, and the MAXI team. J.J.R.R. acknowledges the support by the Matsumae International Foundation Research Fellowship No14G04, and also thanks the entire MAXI team for the collaboration and hospitality in RIKEN. The work of A.G.G. has been supported by the Spanish MICINN under FPI Fellowship BES-2011-050874 associated to the project AYA2010-15431. T.M. acknowledges the grant by the Vicerectorat d’Investigació, Desenvolupament i Innovació de la Universitat d’Alacant under visiting researcher programme INV14-11

Preliminary design of d-pinitol production process from carob extract

[EN] D-pinitol is a cyclic polyalcohol, which has become increasingly important in recent years, especially in pharmacology, due to its interesting properties regarding the treatment of certain diseases, such as diabetes. This, in conjunction with the fact that its synthesis process has been proved to be too costly, means that it is a high value-added substance. It has been noted that its content in some plant species can be abundant; however, this is a field that has not yet been extensively developed. In this work, it is studied how to obtain it from a vegetal extract obtained from carob, after the removal of other major components such as sugars. The work proposes an extraction and purification process of D-pinitol obtaining, and describes the start-up of the process at laboratory scale, testing for it several experimental stages, such as biofermentation, liquid-liquid extractions, or thermal operations, among others. The optimal sequence of the different stages is also studied, along with other key parameters like inoculation rates, reaction timing, appropriate temperature range or the solvents¿ influence, comparing the effects of each parameter on the final product¿s characteristics.[ES] El D-pinitol es un polialcohol cíclico que ha ganado interés en los últimos años, especialmente en el sector farmacológico por sus propiedades para el tratamiento de ciertas enfermedades como la diabetes. Esto, junto con su costosa obtención por medio de síntesis, le confieren un elevado valor añadido. Se ha observado que su presencia en ciertas especies vegetales puede llegar a ser bastante importante, sin embargo, éste todavía es un campo que no ha sido desarrollado ampliamente. En este trabajo se estudia cómo llevar a cabo su obtención a partir de un extracto vegetal obtenido de la algarroba, tras la separación de otros componentes mayoritarios como los azúcares. En el trabajo se propone un proceso de extracción y purificación de D-pinitol, y se describe su puesta a punto a escala de laboratorio, probando para ello diversas etapas, como una biofermentación, extracciones líquido-líquido o procesos térmicos, entre otras. Se estudia además el orden óptimo de las operaciones, y otros parámetros característicos como tasas de inoculación y tiempos de reacción, rangos de temperatura de operación adecuados, o la influencia del disolvente, comparando el efecto de cada modificación con las características del producto final.Giménez García, I.; Arnal Arnal, JM.; Sancho, M.; García-Fayos, B. (2019). Diseño preliminar de un proceso de obtención de d-pinitol a partir del extracto de algarroba. AEIPRO. 778-790. http://hdl.handle.net/10251/181233S77879

Comparative Analysis of Chromatin-Delivered Biomarkers in the Monitoring of Sepsis and Septic Shock: A Pilot Study

[EN] Sepsis management remains one of the most important challenges in modern clinical practice. Rapid progression from sepsis to septic shock is practically unpredictable, hence the critical need for sepsis biomarkers that can help clinicians in the management of patients to reduce the proba-bility of a fatal outcome. Circulating nucleoproteins released during the inflammatory response to infection, including neutrophil extracellular traps, nucleosomes, and histones, and nuclear pro-teins like HMGB1, have been proposed as markers of disease progression since they are related to inflammation, oxidative stress, endothelial damage, and impairment of the coagulation response, among other pathological features. The aim of this work was to evaluate the actual potential for decision making/outcome prediction of the most commonly proposed chromatin-related bi-omarkers (i.e., nucleosomes, citrullinated H3, and HMGB1). To do this, we compared different ELISA measuring methods for quantifying plasma nucleoproteins in a cohort of critically ill pa-tients diagnosed with sepsis or septic shock compared to nonseptic patients admitted to the inten-sive care unit (ICU), as well as to healthy subjects. Our results show that all studied biomarkers can be used to monitor sepsis progression, although they vary in their effectiveness to separate sepsis and septic shock patients. Our data suggest that HMGB1/citrullinated H3 determination in plasma is potentially the most promising clinical tool for the monitoring and stratification of septic patients.This activity received funding from the European Institute of Innovation and Technology (EIT). This body of the European Union receives support from the European Union's Horizon 2020 research and innovation program. C.R-M. thanks GVA for starting grant (GV/2018/127) and Spanish Ministry of Science and Innovation for research project (PID2020-119127RA-I00); J.B-G thanks ISCIII, AES2018 for iPFIS fellowship (IFI18/00015) and GVA for APOTI fellowship (APOTIP/2017/012); CG thanks Spanish Ministry of Universities for fellowship FPU18/03969; J.L.G-G and F.V.P thank INCLIVA, GVA and AES2016 and AES2019 (ISCIII) for starting grant (GV/2014/132), project PI16/01036 and PI19/00994 and project DTS17/00132 (co-financed by the ERDF). The project leading to these results has received funding from "la Caixa" Foundation (ID 100010434), under agreement CI18-0009. C.R-M., F.V.P. and A.M. thank Grand Challenges Canada. : We want to particularly acknowledge the patients and the INCLIVA Biobank (PT17/0015/0049; B.000768 ISCIII) integrated in the Valencian Biobanking Network and the Spanish National Biobanks Network for their collaboration.Beltrán-García, J.; Manclus Ciscar, JJ.; García-López, EM.; Carbonell, N.; Ferreres, J.; Rodríguez-Gimillo, M.; Garcés, C.... (2021). Comparative Analysis of Chromatin-Delivered Biomarkers in the Monitoring of Sepsis and Septic Shock: A Pilot Study. International Journal of Molecular Sciences. 22(18):1-15. https://doi.org/10.3390/ijms22189935115221

Searching for unknown counterparts in X-ray binary systems using Virtual Observatory tools

In the framework of an ongoing programme, we have developed strategies to discover and characterize optical/infrared unknown counterparts to X-ray binary systems using the standard tools of the Virtual Observatory. First, we have selected some potential candidates from different X-ray catalogues. Then we have used the Virtual Observatory tools to search for optical and infrared point data sources that were coincident with the position of the X-ray source. In this work we present some examples of our ongoing programme showing the potential of the Virtual Observatory as a discovery tool.Part of this work was supported by the Spanish Ministry of Education and Science project number AYA2010-15431, by the Vicerectorat d'Investigació, Desenvolupament i Innovació de la Universitat d'Alacant project number GRE12-35, and by the Generalitat Valenciana project number GV2014/088. JJRR acknowledges the support by the Matsumae International Foundation Research Fellowship program 2014, No14G04

An XMM-Newton view of FeKα in high-mass X-ray binaries

We present a comprehensive analysis of the whole sample of available XMM-Newton observations of high-mass X-ray binaries (HMXBs) until August 2013, focusing on the FeKα emission line. This line is key to better understanding the physical properties of the material surrounding the X-ray source within a few stellar radii (the circumstellar medium). We collected observations from 46 HMXBs and detected FeKα in 21 of them. We used the standard classification of HMXBs to divide the sample into different groups. We find that (1) different classes of HMXBs display different qualitative behaviours in the FeKα spectral region. This is visible especially in SGXBs (showing ubiquitous Fe fluorescence but not recombination Fe lines) and in γ Cass analogues (showing both fluorescent and recombination Fe lines). (2) FeKα is centred at a mean value of 6.42 keV. Considering the instrumental and fits uncertainties, this value is compatible with ionization states that are lower than Fe xviii. (3) The flux of the continuum is well correlated with the flux of the line, as expected. Eclipse observations show that the Fe fluorescence emission comes from an extended region surrounding the X-ray source. (4) We observe an inverse correlation between the X-ray luminosity and the equivalent width of FeKα (EW). This phenomenon is known as the X-ray Baldwin effect. (5) FeKα is narrow (σline< 0.15 keV), reflecting that the reprocessing material does not move at high speeds. We attempt to explain the broadness of the line in terms of three possible broadening phenomena: line blending, Compton scattering, and Doppler shifts (with velocities of the reprocessing material V ~ 1000 km s-1). (6) The equivalent hydrogen column (NH) directly correlates to the EW of FeKα, displaying clear similarities to numerical simulations. It highlights the strong link between the absorbing and the fluorescent matter. (7) The observed NH in supergiant X-ray binaries (SGXBs) is in general higher than in supergiant fast X-ray transients (SFXTs). We suggest two possible explanations: different orbital configurations or a different interaction compact object – wind. (8) Finally, we analysed the sources IGR J16320-4751 and 4U 1700-37 in more detail, covering several orbital phases. The observed variation in NH between phases is compatible with the absorption produced by the wind of their optical companions. The results clearly point to a very important contribution of the donor’s wind in the FeKα emission and the absorption when the donor is a supergiant massive star.The work of A.G.G. has been supported by the Spanish MICINN under FPI Fellowship BES-2011-050874 associated to the project AYA2010-15431. This work was supported partially by the Generalitat Valenciana project number GV2014/088 and by the Vicerectorat d’Investigació, Desenvolupament i Innovació de la Universitat d’Alacant under grant GRE12-35. J.J.R.R. acknowledges the support by the Matsumae International Foundation fellowship No14G04

An XMM-Newton view of FeKα in High Mass X-rays Binaries

We present a comprehensive analysis of the whole sample of available XMM-Newton observations of High Mass X-ray Binaries (HMXBs) until August, 2013, focusing on the FeKα emission line. This line is a key tool to better understand the physical properties of the material surrounding the X-ray source within a few stellar radii (the circumstellar medium). We have collected observations from 46 HMXBs, detecting FeKα in 21 of them. We have used the standard classification of HMXBs to divide the sample in different groups. We find that: (1) FeKα is centred at a mean value of 6.42 keV. Considering the instrumental and fits uncertainties, this value is compatible with ionization states lower than Fe XVIII. (2) The flux of the continuum is well correlated with the flux of the line, as expected. Eclipse observations show that the Fe fluorescence emission comes from an extended region surrounding the X-ray source. (3) FeKα is narrow (σ_{line}<0.15 keV), reflecting that the reprocessing material does not move at high speeds. We attempt to explain the broadness of the line in terms of three possible broadening phenomena: line blending, Compton scattering and Doppler shifts (with velocities of the reprocessing material V ∼ 1000 km/s). (4) The equivalent hydrogen column (N_H) directly correlates with the EW of FeKα, displaying clear similarities to numerical simulations. It highlights the strong link between the absorbing and the fluorescent matter. The obtained results clearly point to a very important contribution of the donor's wind in the FeKα emission and the absorption when the donor is a supergiant massive star.Based on observations obtained with XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA member states and the USA (NASA). This research has made use of software obtained from NASA’s High Energy Astrophysics Science Archive Research Center (HEASARC). The work of AGG has been supported by the Spanish MICINN under FPI Fellowship BES-2011-050874 associated to the project AYA2010-15431