Implementación en VLSI de un modelo de aprendizaje con plasticidad basado en calcio

Descargue el texto completo en el repositorio institucional de la Universität Bielefeld: https://pub.uni-bielefeld.de/record/2919341Los sistemas autónomos deben poder adaptarse a un entorno en constante cambio. Esta adaptabilidad requiere importantes recursos computacionales dedicados al aprendizaje, sin embargo, los sistemas artificiales actuales carecen de estos recursos en comparación con los humanos y los animales. Nuestro objetivo es producir redes neuronales con spikes con VLSI que presenten estructuras de aprendizaje similares a las de la biología con el objetivo de lograr el rendimiento y la eficiencia de los sistemas naturales. La literatura de neurociencia sugiere que los iones de calcio juegan un papel clave en la explicación de la dependencia de la plasticidad sináptica a largo plazo de múltiples factores, como el tiempo de los spikes y la frecuencia de los estímulos. Aquí presentamos una implementación VLSI novedosa de un modelo de plasticidad sináptica basado en calcio, comparaciones entre el modelo y las simulaciones de circuito, y mediciones del circuito fabricado.This thesis aims at the implementation of biologically inspired learning algorithm to be embedded in full-custom VLSI spiking neural networks with the goal of constructing compact real-time low-power learning systems with potential application in computational neuroscience basic research investigation, and applications where input data is ambiguous such as in patter recognition. The starting point of this research is based on recent studies that demonstrated a key role of calcium ions for long term synaptic plasticity. These experimental results have inspired mathematical models and hardware implementations of calcium based learning algorithms. Here I present two prototypes of a novel Very-large-scale Integration (VLSI) implementation of a recently proposed calcium-based learning algorithm, its circuital and computation model simulation results and comparison with the mathematical model. The second improved circuit corrects errors observed in the first chip and it is connected to a low-power neuron in a small array. The elaboration of this learning system embedded in a chip provides insight and significant progress in the complex task to understand how to build brain-like integrated systems. This system can be used also as a tool for validating hypotheses arising from experimental observations of biological systems and computational models.Alemania. Center of Excellence - Cognitive Interaction Technology. Beca CITe

Identify. Quantify. Predict. Why immunologists should widely use molecular imaging for Coronavirus Disease 2019

Molecular imaging using PET/CT or PET/MRI has evolved from an experimental imaging modality at its inception in 1972 to an integral component of diagnostic procedures in oncology, and, to lesser extent, in cardiology and neurology, by successfully offerin

Evaluación de riesgo por flujo de detrito en la ciudad de Calca – Cusco (2018)

The present document shows the result from the study “Risk Assessment for Detritus flow in the City of Calca- Cusco (2018)”, elaborated before the possibility of occurrence from this natural phenomenon, with the purpose of proposing control measures that lead to reduce the risk of a disaster in this city. The study is made according to the methodological requirements established by the National Center for Disaster Risk Estimation, Prevention and Reduction. (CENEPRED).El presente documento expone el resultado del estudio “Evaluación de Riesgo por Flujo de Detrito en la ciudad de Calca – Cusco (2018)”, elaborado ante la posibilidad de ocurrencia de este fenómeno natural, con el propósito de plantear medidas de control que conduzcan a reducir el riesgo de un desastre en esta ciudad. El estudio está hecho según los requisitos metodológicos establecidos por el Centro Nacional de Estimación, Prevención y Reducción del Riesgo de Desastres (CENEPRED).Este documento apresenta os resultados do estudo "Risk Assessment for Debris Flow in the City of Calca - Cusco (2018)", preparado no caso da possibilidade da ocorrência deste fenômeno natural, com o objetivo de propor medidas de controle que levem a reduzir o risco de um desastre nesta cidade. O estudo é feito de acordo com os requisitos metodológicos estabelecidos pelo Centro Nacional de Estimação, Prevenção e Redução de Riscos de Desastres (CENEPRED)

Caudal y diseño del sistema de drenaje superficial para la protección de un depósito de desmontes de mina en el departamento de La Libertad, 2022

La investigación se realizó en Lima, en la Universidad Cesar Vallejo, se determinó el caudal y diseño del sistema de drenaje superficial para la protección de un depósito de desmontes de mina, durante el desarrollo de la tesis se usó un diseño no experimental, el muestreo fue no probabilístico, por juicio; las técnicas usadas para la recolección de datos fueron la observación directa y el análisis de documento, los instrumentos usados fueron las fichas de recolección de datos 1 y 2, las fichas de registro 1, 2 y 3, asimismo el método de análisis de datos usado fue la estadística descriptiva, el problema se centra en saber cuál es el caudal de un área determinada, para realizar el diseño de un sistema de drenaje superficial como método de control de escorrentía superficial, evitando riesgo de colapso del depósito de desmontes, riesgo de afectación a vías cercanas, pérdidas de vidas por colapsos, perdidas de ecosistemas circundantes, contaminación de aguas de escorrentía pluvial y generación de drenaje ácido, el caudal determinado fue de 15.80 m3 /s, finalmente se concluyó que el tiempo de vida útil del sistema de drenaje proyectado fue de 100 años con una precipitación de 111.31 mm

VLSI implementation of a calcium-based plasticity learning model

Maldonado Huayaney FL. VLSI implementation of a calcium-based plasticity learning model. Bielefeld: Universität Bielefeld; 2018.A key feature of autonomous systems is the ability to solve computationally intensive tasks while adapting to changes in the environment; therefore, in these systems learning is needed to predict the responses of the environment to the system actions, thus guiding the system to achieve its goals. However, the learning capabilities required for this feature are underdeveloped in artificial systems, especially when compared to those of humans and animals. Highly-computational processors are embedded in chip technology (i.e. CPU and GPU) which every year uses lower dimension transistors yielding high speed, low leakage power, and low cost per transistor. However, the conventional approach to computation, based on the von Neumann architecture with separate units for information storage and processing, is still outperformed in energy efficiency by biological nervous systems in cognitive tasks, such as classification and prediction, where the input data is characterized by ambiguity and uncertainty. In this sense neuromorphic engineering solves specific tasks which are easily performed by biological systems using computational models discovered in biological organisms and where classical processors' architecture would have difficulties. This thesis aims at the implementation of biologically inspired learning algorithm to be embedded in full-custom VLSI spiking neural networks with the goal of constructing compact real-time low-power learning systems with potential application in computational neuroscience basic research investigation, and applications where input data is ambiguous such as in patter recognition. The starting point of this research is based on recent studies that demonstrated a key role of calcium ions for long term synaptic plasticity. These experimental results have inspired mathematical models and hardware implementations of calcium based learning algorithms. Here I present two prototypes of a novel Very-large-scale Integration (VLSI) implementation of a recently proposed calcium-based learning algorithm, its circuital and computation model simulation results and comparison with the mathematical model. The second improved circuit corrects errors observed in the first chip and it is connected to a low-power neuron in a small array. The elaboration of this learning system embedded in a chip provides insight and significant progress in the complex task to understand how to build brain-like integrated systems. This system can be used also as a tool for validating hypotheses arising from experimental observations of biological systems and computational models

Superconducting gap and vortex lattice of the heavy fermion compound CeCu_2Si_2

The order parameter and pairing mechanism for superconductivity in heavy fermion compounds are still poorly understood. Scanning tunneling microscopy and spectroscopy at ultra-low temperatures can yield important information about the superconducting order parameter and the gap structure. Here, we study the first heavy fermion superconductor, CeCu_2Si_2. Our data show the superconducting gap which is not fully formed and exhibits features that point to a multi-gap order parameter. Spatial mapping of the zero bias conductance in magnetic field reveals the vortex lattice, which allows us to unequivocally link the observed conductance gap to superconductivity in CeCu_2Si_2. The vortex lattice is found to be predominantly triangular with distortions at fields close to \sim 0.7 H_{c2}.Comment: 6 pages, 4 figures, revised version accepted for publication in PR

Enhanced health event detection and influenza surveillance using a joint Veterans Affairs and Department of Defense biosurveillance application

<p>Abstract</p> <p>Background</p> <p>The establishment of robust biosurveillance capabilities is an important component of the U.S. strategy for identifying disease outbreaks, environmental exposures and bioterrorism events. Currently, U.S. Departments of Defense (DoD) and Veterans Affairs (VA) perform biosurveillance independently. This article describes a joint VA/DoD biosurveillance project at North Chicago-VA Medical Center (NC-VAMC). The Naval Health Clinics-Great Lakes facility physically merged with NC-VAMC beginning in 2006 with the full merger completed in October 2010 at which time all DoD care and medical personnel had relocated to the expanded and remodeled NC-VAMC campus and the combined facility was renamed the Lovell Federal Health Care Center (FHCC). The goal of this study was to evaluate disease surveillance using a biosurveillance application which combined data from both populations.</p> <p>Methods</p> <p>A retrospective analysis of NC-VAMC/Lovell FHCC and other Chicago-area VAMC data was performed using the ESSENCE biosurveillance system, including one infectious disease outbreak (Salmonella/Taste of Chicago-July 2007) and one weather event (Heat Wave-July 2006). Influenza-like-illness (ILI) data from these same facilities was compared with CDC/Illinois Sentinel Provider and Cook County ESSENCE data for 2007-2008.</p> <p>Results</p> <p>Following consolidation of VA and DoD facilities in North Chicago, median number of visits more than doubled, median patient age dropped and proportion of females rose significantly in comparison with the pre-merger NC-VAMC facility. A high-level gastrointestinal alert was detected in July 2007, but only low-level alerts at other Chicago-area VAMCs. Heat-injury alerts were triggered for the merged facility in June 2006, but not at the other facilities. There was also limited evidence in these events that surveillance of the combined population provided utility above and beyond the VA-only and DoD-only components. Recorded ILI activity for NC-VAMC/Lovell FHCC was more pronounced in the DoD component, likely due to pediatric data in this population. NC-VAMC/Lovell FHCC had two weeks of ILI activity exceeding both the Illinois State and East North Central Regional baselines, whereas Hines VAMC had one and Jesse Brown VAMC had zero.</p> <p>Conclusions</p> <p>Biosurveillance in a joint VA/DoD facility showed potential utility as a tool to improve surveillance and situational awareness in an area with Veteran, active duty and beneficiary populations. Based in part on the results of this pilot demonstration, both agencies have agreed to support the creation of a combined VA/DoD ESSENCE biosurveillance system which is now under development.</p

Left subclavian artery coverage during thoracic endovascular aortic aneurysm repair does not mandate revascularization

ObjectiveThis study assessed the risk of left subclavian artery (LSA) coverage and the role of revascularization in a large population of patients undergoing thoracic endovascular aortic aneurysm repair.MethodsA retrospective multicenter review of 1189 patient records from 2000 to 2010 was performed. Major adverse events evaluated included cerebrovascular accident (CVA) and spinal cord ischemia (SCI). Subgroup analysis was performed for noncovered LSA (group A), covered LSA (group B), and covered/revascularized LSA (group C).ResultsOf 1189 patients, 394 had LSA coverage (33.1%), and 180 of these patients (46%) underwent LSA revascularization. In all patients, emergency operations (9.5% vs 4.3%; P = .001), renal failure (12.7% vs 5.3%; P = .001), hypertension (7% vs 2.3%; P = .01), and number of stents placed (1 = 3.7%, 2 = 7.4%, ≥3 = 10%; P = .005) were predictors of SCI. History of cerebrovascular disease (9.6% vs 3.5%; P = .002), chronic obstructive pulmonary disease (9.5% vs 5.4%; P = .01), coronary artery disease (8.5% vs 5.3%; P = .03), smoking (8.9% vs 4.2%) and female gender (5.3% men vs 8.2% women; P = .05) were predictors of CVA. Subgroup analysis showed no significant difference between groups B and C (SCI, 6.3% vs 6.1%; CVA, 6.7% vs 6.1%). LSA revascularization was not protective for SCI (7.5% vs 4.1%; P = .3) or CVA (6.1% vs 6.4%; P = .9). Women who underwent revascularization had an increased incidence of CVA event compared with all other subgroups (group A: 5.6% men, 8.4% women, P = .16; group B: 6.6% men, 5.3% women, P = .9; group C: 2.8% men, 11.9% women, P = .03).ConclusionsLSA coverage does not appear to result in an increased incidence of SCI or CVA event when a strategy of selective revascularization is adopted. Selective LSA revascularization results in similar outcomes among the three cohorts studied. Revascularization in women carries an increased risk of a CVA event and should be reserved for select cases

Efecto de la cotización internacional del cobre en la recaudación del impuesto a la renta empresarial del sector minero

Objective: Establish the effect of the international copper price’s quote on the corporate income tax collection (RIRE) of the Peruvian mining sector for the period 2004-2020. Method: The design was non-experimental, retrospective, cross-sectional and analytical, with a quantitative, descriptive, correlational, and explanatory approach. In this sense, inferential statistics were used, applying the Shapiro Wilk normality test, as well as hypothesis tests to determine the relationship between the study variables and regression analysis to establish the impact between them. Result: There is a positive relationship between the international copper price and the corporate income tax collection of the Peruvian mining sector, with a correlation degree of 86,9% and a determination coefficient of 75,52%, at a confidence level of 99%. Conclusion: The international copper price did affect the corporate income tax collection of the Peruvian mining sector in the period 2004-2020.Objetivo: Establecer el efecto de la cotización internacional del precio del cobre en la recaudación del impuesto a la renta empresarial (RIRE) del sector minero peruano correspondiente al periodo 2004-2020. Método: El diseño fue no experimental, retrospectivo, transversal y analítico, con enfoque cuantitativo, de tipo descriptivo, correlacional y explicativo. En ese sentido, se recurrió a la estadística inferencial, aplicando la prueba de normalidad de Shapiro Wilk, así como a pruebas de hipótesis para determinar la relación entre las variables de estudio y el análisis de regresión para establecer el impacto entre las mismas. Resultado: Existe una relación positiva entre la cotización internacional del precio del cobre y la RIRE del sector minero peruano, con un grado de correlación de 86,9% y un coeficiente de determinación de 75,52%, a un nivel de confianza de 99%. Conclusión: La cotización internacional del precio del cobre sí afectó en la RIRE del sector minero peruano en el periodo 2004-2020

Endovascular-first approach is not associated with worse amputation-free survival in appropriately selected patients with critical limb ischemia

ObjectiveEndovascular interventions for critical limb ischemia are associated with inferior limb salvage (LS) rates in most randomized trials and large series. This study examined the long-term outcomes of selective use of endovascular-first (endo-first) and open-first strategies in 302 patients from March 2007 to December 2010.MethodsEndo-first was selected if (1) the patient had short (5-cm to 7-cm occlusions or stenoses in crural vessels); (2) the disease in the superficial femoral artery was limited to TransAtlantic Inter-Society Consensus II A, B, or C; and (3) no impending limb loss. Endo-first was performed in 187 (62%), open-first in 105 (35%), and 10 (3%) had hybrid procedures.ResultsThe endo-first group was older, with more diabetes and tissue loss. Bypass was used more to infrapopliteal targets (70% vs 50%, P = .031). The 5-year mortality was similar (open, 48%; endo, 42%; P = .107). Secondary procedures (endo or open) were more common after open-first (open, 71 of 105 [68%] vs endo, 102 of 187 [55%]; P = .029). Compared with open-first, the 5-year LS rate for endo-first was 85% vs 83% (P = .586), and amputation-free survival (AFS) was 45% vs 50% (P = .785). Predictors of death were age >75 years (hazard ratio [HR], 3.3; 95% confidence interval [CI], 1.7-6.6; P = .0007), end-stage renal disease (ESRD) (HR, 3.4; 95% CI, 2.1-5.6; P < .0001), and prior stroke (HR, 1.6; 95% CI, 1.03-2.3; P = .036). Predictors of limb loss were ESRD (HR, 2.5; 95% CI, 1.2-5.4; P = .015) and below-the-knee intervention (P = .041). Predictors of worse AFS were older age (HR, 2.03; 95% CI, 1.13-3.7; P = .018), ESRD (HR, 3.2; 95% CI, 2.1-5.11; P < .0001), prior stroke (P = .0054), and gangrene (P = .024).ConclusionsAt 5 years, endo-first and open-first revascularization strategies had equivalent LS rates and AFS in patients with critical limb ischemia when properly selected. A patient-centered approach with close surveillance improves long-term outcomes for both open and endo approaches