Truncated Variational Sampling for "Black Box" Optimization of Generative Models

We investigate the optimization of two probabilistic generative models with binary latent variables using a novel variational EM approach. The approach distinguishes itself from previous variational approaches by using latent states as variational parameters. Here we use efficient and general purpose sampling procedures to vary the latent states, and investigate the "black box" applicability of the resulting optimization procedure. For general purpose applicability, samples are drawn from approximate marginal distributions of the considered generative model as well as from the model's prior distribution. As such, variational sampling is defined in a generic form, and is directly executable for a given model. As a proof of concept, we then apply the novel procedure (A) to Binary Sparse Coding (a model with continuous observables), and (B) to basic Sigmoid Belief Networks (which are models with binary observables). Numerical experiments verify that the investigated approach efficiently as well as effectively increases a variational free energy objective without requiring any additional analytical steps

Validity of rapid estimates of household wealth and income for health surveys in rural Africa

Drawing data from four different integrated household surveys in rural areas of Mali, Malawi, and two national surveys in Côte d'Ivoire, this paper tests the validity of proxy measures of household wealth and income that can be readily implemented in health surveys in rural Africa. The assumptions underlying the choice of wealth proxy are described, and correlations with the true value are assessed in two different settings. The expenditure proxy is developed and then tested for replicability in two independent data sets representing the same population. The study found that in both Mali and Malawi, the wealth proxy correlated highly (r $ 0.74) with the more complex monetary value method. For rural areas of Côte d'Ivoire, it was possible to generate a list of just 10 expenditure items, the values of which, when summed, correlated highly with expenditures on all items combined (r = 0.74, development data set; r = 0.72, validation data set). Total household expenditure is an accepted alternative measure of household wealth and income in developing country settings. This paper thus shows that it can be feasible to approximate both household wealth and expenditures in rural African settings without dramatically lengthening questionnaires whose primary focus is on health.Africa Rural conditions. ,Household surveys. ,Income Rural areas Africa. ,Health surveys. ,

Content addressable memory project

A parameterized version of the tree processor was designed and tested (by simulation). The leaf processor design is 90 percent complete. We expect to complete and test a combination of tree and leaf cell designs in the next period. Work is proceeding on algorithms for the computer aided manufacturing (CAM), and once the design is complete we will begin simulating algorithms for large problems. The following topics are covered: (1) the practical implementation of content addressable memory; (2) design of a LEAF cell for the Rutgers CAM architecture; (3) a circuit design tool user's manual; and (4) design and analysis of efficient hierarchical interconnection networks

From time-series to complex networks: Application to the cerebrovascular flow patterns in atrial fibrillation

A network-based approach is presented to investigate the cerebrovascular flow patterns during atrial fibrillation (AF) with respect to normal sinus rhythm (NSR). AF, the most common cardiac arrhythmia with faster and irregular beating, has been recently and independently associated with the increased risk of dementia. However, the underlying hemodynamic mechanisms relating the two pathologies remain mainly undetermined so far; thus the contribution of modeling and refined statistical tools is valuable. Pressure and flow rate temporal series in NSR and AF are here evaluated along representative cerebral sites (from carotid arteries to capillary brain circulation), exploiting reliable artificially built signals recently obtained from an in silico approach. The complex network analysis evidences, in a synthetic and original way, a dramatic signal variation towards the distal/capillary cerebral regions during AF, which has no counterpart in NSR conditions. At the large artery level, networks obtained from both AF and NSR hemodynamic signals exhibit elongated and chained features, which are typical of pseudo-periodic series. These aspects are almost completely lost towards the microcirculation during AF, where the networks are topologically more circular and present random-like characteristics. As a consequence, all the physiological phenomena at microcerebral level ruled by periodicity - such as regular perfusion, mean pressure per beat, and average nutrient supply at cellular level - can be strongly compromised, since the AF hemodynamic signals assume irregular behaviour and random-like features. Through a powerful approach which is complementary to the classical statistical tools, the present findings further strengthen the potential link between AF hemodynamic and cognitive decline.Comment: 12 pages, 10 figure

Cardiac-specific Conditional Knockout of the 18-kDa Mitochondrial Translocator Protein Protects from Pressure Overload Induced Heart Failure.

Heart failure (HF) is characterized by abnormal mitochondrial calcium (Ca2+) handling, energy failure and impaired mitophagy resulting in contractile dysfunction and myocyte death. We have previously shown that the 18-kDa mitochondrial translocator protein of the outer mitochondrial membrane (TSPO) can modulate mitochondrial Ca2+ uptake. Experiments were designed to test the role of the TSPO in a murine pressure-overload model of HF induced by transverse aortic constriction (TAC). Conditional, cardiac-specific TSPO knockout (KO) mice were generated using the Cre-loxP system. TSPO-KO and wild-type (WT) mice underwent TAC for 8 weeks. TAC-induced HF significantly increased TSPO expression in WT mice, associated with a marked reduction in systolic function, mitochondrial Ca2+ uptake, complex I activity and energetics. In contrast, TSPO-KO mice undergoing TAC had preserved ejection fraction, and exhibited fewer clinical signs of HF and fibrosis. Mitochondrial Ca2+ uptake and energetics were restored in TSPO KO mice, associated with decreased ROS, improved complex I activity and preserved mitophagy. Thus, HF increases TSPO expression, while preventing this increase limits the progression of HF, preserves ATP production and decreases oxidative stress, thereby preventing metabolic failure. These findings suggest that pharmacological interventions directed at TSPO may provide novel therapeutics to prevent or treat HF

Intercorelation of Turbidty with Primary Productivity and Nutrient in the Water East Sungaitohor of Sub-district of East Tebingtinggi, District of Kepulauan Meranti, Province of Riau

The objective of the research is to find out water quality condition in most coastal water in East Sungaitohor especially turbidity and its effect toward water primary productivity and its nutrient. This research has been conducted in Sungaitohor waters, district of Kepulauan Meranti. The methods used is purposive sampling. Sampling has been conducted on March 4th, 2017 and nitrate, phospate analysis and turbidity conducted in Marine Chemistry Laboratory and phytoplankton identification has been conducted in Marine Biology in March 10th, 2017. The result shows that the range of turbidity in the waters around 32,07-190 NTU, nitrate consentration is about 2,325-2,4291 mg/L and phospate consentration around -0,5 – 5 mgC/m2/day. Corelation between turbidity and primary productivity, phitoplankton, nitrate, and phospate respectively shows very weak, moderate, moderate, and weak