Spike Train Statistics from Empirical Facts to Theory: The Case of the Retina

International audienceThis chapter focuses on methods from statistical physics and probability theory allowing the analysis of spike trains in neural networks. Taking as an example the retina we present recent works attempting to understand how retina ganglion cells encode the information transmitted to the visual cortex via the optical nerve, by analyzing their spike train statistics. We compare the maximal entropy models used in the literature of retina spike train analysis to rigorous results establishing the exact form of spike train statistics in conductance-based Integrate-and-Fire neural networks

Determinación del nivel de filtración que tiene la cáscara de plátano, para reducir metales pesados presentes en agua residual en la empresa weatherford, cantón Francisco de Orellana, provincia de Orellana, periodo 2014

Banana's peel consists substances and specific qualities which ones allow metals heavy reduction as possible. About shell composition we can emphasize the hydroxylated and carboxylated pectin presence; these substances are able to absorb heavy metals, and there are studies to ensure compounds organic absorption. Based on previous explanation, the present investigation was conducted with the main objective to determine filtration level that has the banana's peel to reduce heavy metals in water, specifically Barium, Cadmium, Chromium, Lead, Nickel and Vanadium. Therefore, physical and chemical analyzes were performed in an accredited laboratory by the Ecuadorian Accreditation Organization (OAE), industry Weatherford effluent, thus to know if there is metals heavy presence in laboratory studio. Laboratory reports out a high presence of these pollutants in the effluent, but these low levels do not stop being a notorious problem for tools, equipment and piping, which ones are washed with this industrial effluent, after this water industrial system has passed a treatment currently given by the company and corrosion is almost immediate….La cáscara de plátano está compuesta por sustancias y cualidades específicas que permiten que la reducción de los metales pesados sea posible. Entre la composición de la cáscara podemos recalcar la presencia de Hidroxila y Carboxila de Pectina; estas sustancias son capaces de absorber metales pesados e incluso hay estudios que aseguran la absorción de compuestos orgánicos. En base a lo anteriormente mencionado, la presente investigación se la realizo con la finalidad de determinar el nivel de filtración que tiene la cáscara de plátano para reducir metales pesados presentes en agua, específicamente: Bario, Cadmio, Cromo, Plomo, Níquel y Vanadio. Para esto se realizaron análisis físico químicos en un laboratorio acreditado por el Organismo de Acreditación Ecuatoriano (OAE), al efluente industria de Weatherford, para de esta manera conocer si existe la presencia de los metales pesados en estudio…

Gender inequality in Latin American Neuroscience community

Gender bias in Science, Technology, Engineering, and Mathematics (STEM) has been identified since a long time ago. However, gender imbalance in neuroscience has not yet been adequately explored worldwide. Here we report the first study on the development of the careers of men and women neuroscientists in Latin America in relation to family life and their perceptions of obstacles to success. Apart from revealing gender inequality in the neuroscience field, distinctive Latin American traits have become evident, thus providing novel insights into the global comprehension of gender imbalance in the region, which is required for guiding future actions, including the design of public policies in the region.Fil: Silva, Ana. International Brain Research Organization. Latin American Regional Committee; Uruguay. Universidad de la República; UruguayFil: Tomassini, Cecilia. International Brain Research Organization. Latin American Regional Committee; Uruguay. Universidad de la República; UruguayFil: Zurbrigg, Julieta. Economic Commission for Latin America and the Caribbean in Montevideo; UruguayFil: Palacios, Adrian. Centro Interdisciplinario de Neurociencia de Valparaíso; Chile. International Brain Research Organization. Latin American Regional Committee; UruguayFil: Amarante, Verónica. Economic Commission for Latin America and the Caribbean; UruguayFil: Bouzat, Cecilia Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; Argentina. International Brain Research Organization. Latin American Regional Committee; Urugua

Parametric estimation of spike train statistics by Gibbs distributions : an application to bio-inspired and experimental data

We review here the basics of the formalism of Gibbs distributions and its numerical implementation, (its details published elsewhere \cite{vasquez-cessac-etal:10}, in order to characterizing the statistics of multi-unit spike trains. We present this here with the aim to analyze and modeling synthetic data, especially bio-inspired simulated data e.g. from Virtual Retina \cite{wohrer-kornprobst:09}, but also experimental data Multi-Electrode-Array(MEA) recordings from retina obtained by Adrian Palacios. We remark that Gibbs distribution allow us to estimate the spike statistics, given a design choice, but also to compare different models, thus answering comparative questions about the neural code

BPM-SCRUM Integrated Model with Digital Marketing to Increase Patient Recruitment Rate in Mental Health Services

In a pre-pandemic scenario, 350 million people in the world suffer from depression, 60% of whom do not receive treatment. In Peru, every 22 minutes someone tries to take his or her own life. In the world, 800 000 people do so, mainly due to depression. Of the people who suffer from this disease, 75% do not do anything about it. This is due to the barrier of misinformation about mental health, its importance and the services available. In spite of this, in the case of the people who do get treatment, many of them end up abandoning it because it does not meet the special expectations of each patient. Therefore, a redesign of the patient attraction process has been proposed using BPM and Scrum Methodology. This proposal will also apply Digital Marketing to launch a web platform that automates the entire patient recruitment process. The current patient acquisition rate is 50% of the industry standard and the rate of digital tools usage is 60%. After the implementation of the proposed model, these rates increased to 76% and 100%, respectively. Keywords—BPM, SCRUM, digital marketing, mental health service, recruitment rat

Tax Exemptions for SMEs in Colombia in the Period 2010 - 2023

El presente artículo tiene como objetivo principal analizar las exenciones tributarias otorgadas a las PYMES en Colombia durante el periodo comprendido entre 2010 y 2023, mediante una metodología cualitativa de revisión bibliográfica. Entender las exenciones tributarias puede proporcionar información valiosa para el diseño de políticas públicas dirigidas al fortalecimiento y promoción de las PYMES en el país, las PYMES están clasificadas legalmente por el Decreto 957 de 2019 y la Ley 1314 de 2009. La relevancia de este artículo de revisión radica en la necesidad de fomentar un entorno empresarial favorable para las PYMES en Colombia. A pesar de su papel vital en la economía (aportan el 40% al PIB y son el 96% de las empresas nacionales1 ), estas empresas enfrentan desafíos significativos, como barreras financieras, limitaciones de acceso al crédito y una carga tributaria que puede afectar su capacidad para invertir, crecer y competir en el mercado nacional e internacional, así mismo, como afirman Ángel y Córdoba (2019), “el desconocimiento de la norma tributaria por parte de las nuevas compañías PYMES hace necesario que el gobierno implemente estrategias tributarias para apoyar a sus proyectos emprendedores” (p. 9). Por lo anterior mencionado, se investigará al respecto de este tema, teniendo en cuenta los beneficios y desafíos que presentan las PYMES en materia tributaria, para abarcarlo de mejor manera, se dividen también los hallazgos en los últimos tres periodos presidenciales de Colombia (teniendo en cuenta el actual para el año 2023), haciendo así un recorrido por los cambios que se han realizado en los años recientes. 1 Dato citado por Acosta et. al. en su artículo, de los autores Paz Juvinado & Serge Lario, 2019. 2 Esta investigación contribuirá al conocimiento académico y a la toma de decisiones en el ámbito de las políticas públicas relacionadas con las PYMES en Colombia, ya que, además, son el tipo de empresa que más se crea en el país. Los resultados obtenidos permitirán evaluar la efectividad de las exenciones tributarias existentes y proporcionarán recomendaciones para mejorar su diseño y aplicación. Asimismo, se generarán evidencias que respalden la importancia de mantener y fortalecer las políticas de apoyo a las PYMES, en línea con los objetivos de crecimiento económico y desarrollo sostenible del país.Universidad Libre Seccional Pereira -- Facultad de Ciencias Económicas, Administrativas y Contables -- Especialización en gestión tributaria y aduaneraThe main objective of this article is to analyze the tax exemptions granted to SMEs in Colombia during the period between 2010 and 2023, through a qualitative methodology of literature review. Understanding tax exemptions can provide valuable information for the design of public policies aimed at strengthening and promoting SMEs in the country, SMEs are legally classified by Decree 957 of 2019 and Law 1314 of 2009. The relevance of this review article lies in the need to foster a favorable business environment for SMEs in Colombia. Despite their vital role in the economy (they contribute 40% to the GDP and are 96% of national companies ), these companies face significant challenges, such as financial barriers, limitations in access to credit and a tax burden that may affect their ability to invest, grow and compete in the national and international market, likewise, as stated by Angel and Cordoba (2019), "the lack of knowledge of the tax regulations by new SME companies makes it necessary for the government to implement tax strategies to support their entrepreneurial projects" (p. 9). For the above mentioned, research will be conducted on this topic, taking into account the benefits and challenges presented by SMEs in tax matters, to better cover it, the findings are also divided into the last three presidential terms in Colombia (taking into account the current one for the year 2023), thus making a tour of the changes that have been made in recent years. This research will contribute to academic knowledge and decision-making in the field of public policies related to SMEs in Colombia, since they are also the type of company that is most created in the country. The results obtained will make it possible to evaluate the effectiveness of existing tax exemptions and will provide recommendations for improving their design and application. Evidence will also be generated to support the importance of maintaining and strengthening policies to support SMEs, in line with the country's economic growth and sustainable development objectives. Keywords— Tax exemptions, SMEs, income, tax treatment, taxation in Colombia

Dimensionality Reduction in spatio-temporal MaxEnt models and analysis of Retinal Ganglion Cell Spiking Activity in experiments

International audienceRetinal spike response to stimuli is constrained, on one hand by short range correlations (receptive field overlap) and on the other hand by lateral connectivity (cells connectivity). This last effect is difficult to handle fromstatistics because it requires to consider spatio-temporal correlations with a time delay long enough to take into account the time of propagation along synapses. Although MaxEnt model are useful to fit optimal model(maximizing entropy) under the constraints of reproducing observed correlations, they do address spatio-temporal correlations in their classical form (Ising or higher order interactions but without time delay). Binning insuch models somewhat integrates propagation effects, but in an implicit form, and increasing binning severely bias data [1]. To resolve this issue we have considered spatio-temporal MaxEnt model formerly developed e.g.by Vasquez et al. [2]. The price to pay, however is a huge set of parameters that must be fitted to experimental data to explain the observed spiking patterns statistics. There is no a priori knowledge of which parameters arerelevant and which ones are contributing to overfitting. We propose here a method of dimension reduction, i.e. a projection on a relevant subset of parameters, relying on the so-called Susceptibility matrix closely related tothe Fisher information. In contrast to standard methods in information geometry though, this matrix handle space and time correlations.We have applied this method for retina data obtained in a diurnal rodent (Octodon degus, having 30% of cones photoreceptors) and a 252-MEA system. Three types of stimuli were used: spatio-temporal uniform light, whitenoise and a natural movie. We show the role played by time-delayed pairwise interactions in the neural response to stimuli both for close and distant cells. Our conclusion is that, to explain the population spiking statisticswe need both short-distance interactions as well as long-distance interactions, meaning that the relevant functional correlations are mediated not only by common input (i.e. receptive field overlap, electrical coupling;spillover) but also by long range connections

Dimensionality Reduction on Maximum Entropy Models on Spiking Networks

Maximum entropy models (MEM) have been widely used in the last 10 years formodelling, explaining and predicting the statistics of networks of spiking neurons.However, as the network size increases, the number of model parameters increasesrapidily, hindering its interpretation and fast computation. However, these parametersare not necessarily independent from each other; when some of them are related byhidden dependencies, their number can be reduced, allowing to map the MEM into alower dimensional space. Here, we present a novel framework for MEM dimensionalityreduction that uses the geometrical properties of MEM to find the subset of dimensionsthat best captures the network high-order statistics, without fitting the model to data.This allows us define a parameter somehow representing the degree of compressibility ofthe code. The method was tested on synthetic data where the underlying statistics isknown and on retinal ganglion cells (RGC) data recorded using multi-electrode arrays(MEA) under different stimuli. We found that MEM dimensionality reduction dependson the interdependences between the network activity, the density of the raster and thenumber of observed events. For RGC data we found that the activity is highlyinterdependent, with a dimensionality reduction of almost 50%, compared to a randomraster, showing that the network activity is highly compressible, possibly due to thenetwork redundancies. This dimensionality reduction depends on the stimuli statistics,supporting the idea that sensory networks adapts to stimuli statistics, modifying thelevel of redundancy, i.e. the coding strategy

Parametric estimation of spike train statistics by Gibbs distributions : an application to bio-inspired and experimental data

We review here the basics of the formalism of Gibbs distributions and its numerical implementation, (its details published elsewhere \cite{vasquez-cessac-etal:10}, in order to characterizing the statistics of multi-unit spike trains. We present this here with the aim to analyze and modeling synthetic data, especially bio-inspired simulated data e.g. from Virtual Retina \cite{wohrer-kornprobst:09}, but also experimental data Multi-Electrode-Array(MEA) recordings from retina obtained by Adrian Palacios. We remark that Gibbs distribution allow us to estimate the spike statistics, given a design choice, but also to compare different models, thus answering comparative questions about the neural code

Implementation of a psychological online intervention for low to moderate depression in primary care: study protocol

Background: Depression affects millions of people all over the world and implies a great socioeconomic burden. Despite there are different effective evidence-based interventions for treating depression, only a small proportion of these patients receives an appropriate treatment. In this regard, information and communication technologies (ICTs) can be used with therapeutic aims and this can contribute to make interventions more accessible. One example is “Smiling is fun”, an internet-based treatment which has proved to be effective and cost-effective for treating depression in Spanish Primary Care (PC). However, the “know-do gap” between research and clinical settings implies that the actual implementation of such interventions could last up to 20 years. To overcome this obstacle, the implementation research establishes the methodology to implement the advances developed in the laboratories to the health care services maintaining the validity of the intervention and offering specific stra- tegies for the implementation process. Objective: This is the protocol of an implementation study for the Internet-based program “Smiling is fun”, which will be conducted on patients with mild-to-moderate depression of Spanish PC settings. In the implementation study, the feasibility, efficacy, cost-efficacy, acceptability, adoption, appropriateness, fidelity, penetration, normalization, and sustainability will be assessed. Methods: The current investigation is a Hybrid Effectiveness-Implementation Type II design. A Stepped Wedge randomized controlled trial design will be used, with a cohort of 420 adults diagnosed with depression (mild-to- moderate) who will undergo a first control phase (no treatment) followed by the intervention, which will last 16 weeks, and finishing with an optional use of the intervention. All patients will be assessed at baseline, during the treatment, and at post-treatment. The study will be conducted in three Spanish regions: Andalusia, Aragon, and the Balearic Islands. Two primary care centers of each region will participate, one located in the urban setting and the other in the rural setting. The primary outcome will be implementation success of the intervention assessing the reach, clinical effect, acceptability, appropriateness, adoption, feasibility, fidelity, penetration, implementation costs and sustainability services. Discussion: “Smiling is Fun”, which has already been established as effective and cost-effective, will be adapted according to users' experiences and opinions, and the efficacy and cost-efficacy of the program will again be assessed. The study will point out barriers and facilitators to consider in the implementation process of internet- based psychological interventions in health services. The ultimate goal is to break the research-to-practice split, which would undoubtedly contribute to reduce the high burden of depression in our societ