Modeling phone call durations via switching Poisson processes with applications in mental health

Poster of: IEEE 30th International Workshop on Machine Learning for Signal Processing (MLSP 2020 ), 21-24 September 2020, Espoo, FinlandThis work models phone call durations via switching Poisson point processes. This kind of processes is composed by two intertwined intensity functions: one models the start of a call, whereas the other one models when the call ends. Thus, the call duration is obtained from the inverse of the intensity function of finishing a call. Additionally, to model the circadian rhythm present in human behavior, we shall use a (pos-itive) truncated Fourier series as the parametric form of the intensities. Finally, the maximum likelihood estimates of the intensity functions are obtained using a trust region method and the performance is evaluated on synthetic and real data, showing good results.This work was supported by the Ministerio de Ciencia, Innovación y Universidades under grant TEC2017-92552-EXP (aMBITION), by the Ministerio de Ciencia, Innovación y Universidades, jointly with the European Commission (ERDF), under grants TEC2017-86921-C2-2-R (CAIMAN) and RTI2018-099655-BI00 (CLARA), by the Comunidad de Madrid under grant Y2018/TCS-4705 (PRACTICO-CM), and by Fundación BBVA under project Deep-DARWIN

Mixtures of heterogeneous Poisson processes for the assessment of e-social activity in mental health

Proceeding of: NeurIPS 2019 Workshop: Learning with Temporal Point Processes (part of the 33rd Conference on Neural Information Processing Systems), Vancouver, December 14, 2019 (Visit: https://nips.cc/Conferences/2019/Schedule?showEvent=13166 and https://sites.google.com/view/tpp-neurips-2019)This work introduces a novel method to assess the social activity maintained by psychiatric patients using information and communication technologies. In particular, we jointly model using point processes the e-social activity patterns from two heterogeneous sources: the usage of phone calls and social and communication apps. We propose a nonhomogeneous Poisson mixture model with periodic (circadian) intensity function using a truncated Fourier series expansion, which is inferred using a trust-region algorithm, and it is able to cope with the different daily patterns of a person. The analysis of the usage of phone calls and social and communication apps of a cohort of 164 patients reveals that 25 patterns suffice to characterize their daily behavior.This work was supported by the Ministerio de Ciencia, Innovación y Universidades under grant TEC2017-92552-EXP (aMBITION), by the Ministerio de Ciencia, Innovación y Universidades, jointly with the European Commission (ERDF), under grants TEC2017-86921-C2-2-R (CAIMAN) and RTI2018-099655-BI00 (CLARA), and by The Comunidad de Madrid under grant Y2018/TCS-4705 (PRACTICO-CM)

STM-driven transition from rippled to buckled graphene in a spin-membrane model

We consider a simple spin-membrane model for rippling in graphene. The model exhibits transitions from a flat but rippled membrane to a buckled one. At high temperature the transition is second order, but it is first order at low temperature for appropriate strength of the spin-spin coupling. Driving the system across the first-order phase transition in nonequilibrium conditions that mimic interaction of the graphene membrane with a scanning tunneling microscopy (STM) tip explains recent experiments. In particular, we observe a reversible behavior for small values of the STM current and an irreversible transition from a flat rippled membrane to a rigid buckled membrane when the current surpasses a critical value. This work makes it possible to test the mechanical properties of graphene under different temperature and electrostatic conditions.Ministerio de Economía y Competitividad MTM2014-56948- C2-2-

Bone marrow-derived mesenchymal stem cells transplantation produces a tissue recovery in hydrocephalic mice

In congenital hydrocephalus, cerebrospinal fluid accumulation is associated to ischemia/hypoxia, metabolic impairment, neuronal damage and astrocytic reaction, which cause significant mortality and life-long neurological complications. Currently, there are no effective therapies for congenital hydrocephalus. Bone marrow-derived mesenchymal stem cells (BM-MSC) are considered as a potential therapeutic tool for neurodegenerative diseases due to their ability for migrating and producing neuroprotector factors when they are transplanted. The aim of this research was to study the ability of BM-MSC to reach the degenerated regions and to detect their neuroprotector effects, using an animal model of congenital hydrocephalus, the hyh mouse. Fluorescent BM-MSC were analyzed by flow-cytometry and multilineage cell differentiation. BM-MSC were brain-ventricle injected into hyh mice. Wild-type and saline-injected hyh mice were used as controls. Inmunohistochemical, RT-PCR and High Resolution Magic Angle Spinning spectroscopy (HRMAS) analyses were carried out. After administration, integrated BM-MSC were identified inside the periventricular astrocyte reaction. They were detected producing glial-derived neuroprotector factor (GDNF), neural growth factor (NGF), and brain-derived neuroprotector factor (BDNF). Tissue recovery was detected with a reduction of apoptotic cells in the periventricular walls and of the levels of glutamate, glutamine, taurine, and creatine, all of them markers of tissue damage in hydrocephalus.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. ISCIII PI15/00619 y FEDE

Long-time effects of an experimental therapy with mesenchymal stem cells in congenital hydrocephalus

Introduction: Bone marrow-derived mesenchymal stem cells (BM-MSC) are a potential therapeutic tool due to their ability for migrating and producing neuroprotector factors when they are transplanted in other neurodegenerative diseases. Moreover, some investigations have shown that BM-MSC are able to modulate astrocyte activation and neuroprotector factor production. The aim of this study was to evaluate the long-time effects of a BM-MSC experimental therapy in the hyh mouse model of congenital hydrocephalus. Methods: BM-MSC were characterized in vitro and then transplanted into the ventricles of young hydrocephalic hyh mice, before they develop the severe hydrocephalus. Non-hydrocephalic normal mice (wt) and hydrocephalic hyh mice sham-injected (sterile saline serum) were used as controls. Samples were studied by analyzing and comparing mRNA, protein level expressions and immunoreaction related with the progression and severity of hydrocephalus. Results: Fourteen days after transplantation, hydrocephalic hyh mice with BM-MSC showed lower ventriculomegaly. In these animals, BM-MSC were found undifferentiated and spread into the periventricular astrocyte reaction. There, BM-MSC were detected producing several neuroprotector factors (BDNF, GDNF, NGF, VEGF), in the same way as reactive astrocytes. Total neocortical levels of NGF, TGF-β and VEGF were found increased in hydrocephalic hyh mice transplanted with BM-MSC. Furthermore, astrocytes showed increased expressions of aquaporin-4 (water channel protein) and Slit-2 (neuroprotective and anti-inflammatory molecule). Conclusions: BM-MSC seem to lead to recovery of the severe neurodegenerative conditions associated to congenital hydrocephalus mediated by reactive astrocytes.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. PI15/0619 (ISCIII/FEDER

A metabolite profile reveals the presence of neurodegenerative conditions according to severity of hydrocephalus

Introduction: In obstructive congenital hydrocephalus, cerebrospinal fluid accumulation is associated with high intracranial pressure (ICP), ischemia/hypoxia, metabolic impairment, neuronal damage and astrocytic reaction. The hyh mutant mice exhibit two different forms of hydrocephalus evolution: severe and moderate. A study was carried out in hyh mice to detect a metabolite profile that define the tissue response in each hydrocephalus form. Methods: Metabolites levels in brain cortex were analyzed with 1H High Resolution Magic Angle Spinning Nuclear Magnetic Resonance (1H HR-MAS) spectroscopy. The study was complemented with ICP recording and histopathological analysis. Results: Mice with severe hydrocephalus were found to have higher ICP and stronger astrocytic reaction. Several metabolites including glutamate and glutamine were found to correlate with the severity of hydrocephalus. The whole metabolite profile may be explained based in differential astrocyte reactions, neurodegenerative and ischemic conditions. The glutamate transporter EAAT2 and the metabolite taurine were found as key histopathological markers for the damaged parenchyma. Conclusions: Spectroscopy allowed the detection of a metabolite profile related to intracranial pressure and hydrocephalus severity, and therefore can be useful to monitor the efficacy of experimental therapies. Supported by Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech, and PI15/0619 (ISCIII/FEDER).Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. Supported by Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech, and PI15/0619 (ISCIII/FEDER)

Bone marrow-derived mesenchymal stem cells characterization and transplantation in an animal model of congenital hydrocephalus

Congenital hydrocephalus is a disorder presenting a degeneration of the periventricular cerebral parenchyma and the white matter, which causes significant mortality and life-long neurological complications. There are currently no effective therapies for congenital hydrocephalus. Bone marrow-derived mesenchymal stem cells (BM-MSC) are considered as a potential therapeutic tool in neurodegenerative diseases, due to their ability to migrate to degenerated tissues and the production of growth factors. In the present study, using an animal model of congenital hydrocephalus, the hyh mouse, it has been studied the capacity of the BM-MSC to reach the degenerated regions exhibiting glial reactions and their probable neuroprotector effects. The BM-MSC were isolated from two different sources: a) transgenic mice expressing the monomeric red fluorescent protein (mRFP1); b) wild type mice. In the second case, the BM-MSC were labelled in vitro using bromodeoxyuridine, a fluorescent cell tracker and the lipophilic DiR. Before application, the cells were analysed using flow cytometry and immunofluorescence. The BM-MSC were injected into the retro-orbital sinus or into the lateral ventricle of hyh mice. After 24/96 hours of administration, the BM-MSC were detected under light, confocal and electron microscopes. The injected BM-MSC reached the degenerated periventricular regions and the disrupted neurogenic niches. They were detected in the periventricular parenchyma, around periventricular blood vessels and in the ventral meninges. Most of the applied BM-MSC expressed the glial cell-derived neurotrophic factor (GDNF), in the same way as the periventricular reactive astrocytes, suggesting a possible neuroprotector effect.FIS (Instituto de Salud Carlos III)-FEDER a AJJ. Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

Characterization and administration of bone marrow-derived mesenchymal stem cells in an animal model of congenital hydrocephalus

Bone marrow-derived mesenchymal stem cells (BM-MSC) are considered as a potential therapeutic tool in neurodegenerative diseases, due to their ability to migrate to degenerated tissues and the production of growth factors. Congenital hydrocephalus is a disorder characterized by a degeneration of the periventricular cerebral parenchyma and the white matter. In the present study, using an animal model of congenital hydrocephalus, the hyh mouse, it has been studied the capacity of the BM-MSC to reach the degenerated regions exhibiting glial reactions and their probable neuroprotector effects. The BM-MSC were isolated from two sources: a) transgenic mice expressing the monomeric red fluorescent protein (mRFP1); b) wild type mice. In the second case, the BM-MSC were labelled in vitro using bromodeoxyuridine, a fluorescent cell tracker and the lipophilic DiR. Before application, the cells were analysed using flow cytometry and immunofluorescence. The BM-MSC were injected into the retro-orbital sinus or into the lateral ventricle of hyh mice. After 24/96 hours of administration, they were detected under light, confocal and electron microscopes. The injected BM-MSC reached the degenerated periventricular regions and the disrupted neurogenic niches. They were detected in the periventricular parenchyma, around periventricular blood vessels and in the ventral meninges. Most of the applied BM-MSC expressed the glial cell-derived neurotrophic factor (GDNF), in the same way as the periventricular reactive astrocytes, suggesting a possible neuroprotector effect.Universidad de Málaga, Campus de Excelencia Internacional Andalucía Tech. Instituto de Salud Carlos III, PI12/0631 con cofinanciación FEDER

Assessment of Variability in Irregularly Sampled Time Series: Applications to Mental Healthcare

Variability is defined as the propensity at which a given signal is likely to change. There are many choices for measuring variability, and it is not generally known which ones offer better properties. This paper compares different variability metrics applied to irregularly (nonuniformly) sampled time series, which have important clinical applications, particularly in mental healthcare. Using both synthetic and real patient data, we identify the most robust and interpretable variability measures out of a set 21 candidates. Some of these candidates are also proposed in this work based on the absolute slopes of the time series. An additional synthetic data experiment shows that when the complete time series is unknown, as it happens with real data, a non-negligible bias that favors normalized and/or metrics based on the raw observations of the series appears. Therefore, only the results of the synthetic experiments, which have access to the full series, should be used to draw conclusions. Accordingly, the median absolute deviation of the absolute value of the successive slopes of the data is the best way of measuring variability for this kind of time series