Structural time series: computational efficiency in estimating economic parameters in industry

A growing field is related to automatized Time Series analysis, through complicated due to the dependence of observed and hidden dimensions often presented in these data types. In this report the problem is motivated by a Brazilian financial company interested in unraveling relation structure explanation of the Japanese' CPI ex-fresh Food \& Energy across 157 economical exogenous variables, with very limiting data. The problem becomes more complex when considering that each variable can enter the model with lags of 0 to 8 periods, as well as an additional restriction of admitting only a positive relationship. This report discusses three possible treatments involving models for structured time series, the most relevant approach found in this study is a Dynamic Regression Model combined with a Stepwise algorithm, which allows the most relevant variables, as well as their respective lags, to be found and inserted in the model with low computational cost.

Influence of the Landscape Template on Chemical and Physical Habitat for Brown Trout Within a Boreal Stream Network

We used the distribution of stream-dwelling brown trout (Salmo trutta) in a 67 km2 boreal catchment to explore the importance of environmental organizing factors at a range of spatial scales, including whole-catchment characteristics derived from map data, and stream reach chemical and physical characteristics. Brown trout were not observed at any sites characterized by pH < 5.0 during the spring snowmelt episode, matching published toxicity thresholds. Brown trout distributions were patchy even in less acidic regions of the stream network, positively associated with glaciofluvial substrate and negatively associated with fine sand/silty sediments. A multivariate model including only whole-catchment characteristics explained 43% of the variation in brown trout densities, while models with local site physical habitat characteristics or local stream chemistry explained 33 and 25%, respectively. At the stream reach scale, physical habitat apparently played a primary role in organizing brown trout distributions in this stream network, with acidity placing an additional restriction by excluding brown trout from acidic headwater streams. Much of the strength of the catchment characteristics-fish association could be explained by the correlation of catchment-scale landscape characteristics with local stream chemistry and site physical characteristics. These results, consistent with the concept of multiple hierarchical environmental filters regulating the distribution of this fish species, underline the importance of considering a range of spatial scales and both physical and chemical environments when attempting to manage or restore streams for brown trout.

Compositional optimizations for CertiCoq

Compositional compiler verification is a difficult problem that focuses on separate compilation of program components with possibly different verified compilers. Logical relations are widely used in proving correctness of program transformations in higher-order languages; however, they do not scale to compositional verification of multi-pass compilers due to their lack of transitivity. The only known technique to apply to compositional verification of multi-pass compilers for higher-order languages is parametric inter-language simulations (PILS), which is however significantly more complicated than traditional proof techniques for compiler correctness. In this paper, we present a novel verification framework for lightweight compositional compiler correctness . We demonstrate that by imposing the additional restriction that program components are compiled by pipelines that go through the same sequence of intermediate representations , logical relation proofs can be transitively composed in order to derive an end-to-end compositional specification for multi-pass compiler pipelines. Unlike traditional logical-relation frameworks, our framework supports divergence preservation—even when transformations reduce the number of program steps. We achieve this by parameterizing our logical relations with a pair of relational invariants . We apply this technique to verify a multi-pass, optimizing middle-end pipeline for CertiCoq, a compiler from Gallina (Coq’s specification language) to C. The pipeline optimizes and closure-converts an untyped functional intermediate language (ANF or CPS) to a subset of that language without nested functions, which can be easily code-generated to low-level languages. Notably, our pipeline performs more complex closure-allocation optimizations than the state of the art in verified compilation. Using our novel verification framework, we prove an end-to-end theorem for our pipeline that covers both termination and divergence and applies to whole-program and separate compilation, even when different modules are compiled with different optimizations. Our results are mechanized in the Coq proof assistant.

On factorizations into coprime parts

Let [Formula: see text] and [Formula: see text] be the number of unordered and ordered factorizations of [Formula: see text] into integers larger than one. Let [Formula: see text] and [Formula: see text] have the additional restriction that the factors are coprime. We establish asymptotic bounds for the sums of [Formula: see text] and [Formula: see text] up to [Formula: see text] for all real [Formula: see text] and the asymptotic bounds for [Formula: see text] and [Formula: see text] for all negative [Formula: see text].

Pressure Activated Sealant to Restore Tubing Integrity – Case Study of Well Tn-X in Mahakam

Pressure activated sealant is used to repair tubing leak and restore tubing integrity without the need to install downhole devices which yield additional restriction inside tubing and reduce tubing ID. Leak on tubing was detected in early production phase from the continuous increase of A annulus pressure. The leak point was indicated from Production Logging Tool (PLT) at 183 m suspected from tubing thread connection, with annulus pressure buildup rate 435 psi/24 hrs. Pressure activated sealant was selected as the means to cure the leak. Retrievable plug was set below the leak point and sealant was pumped on top of plug, followed by inhibited water. Then pressure was applied at surface to squeeze and activate the sealant. The remaining fluid inside tubing remained liquid, allowing the plug to be retrieved. A total of 59 L sealant mixture and 750 L of inhibited water was pumped to the well. Hesitation pressure was performed to activate the sealant, and got indication of chemical sealing at 1000 psi. The tubing was then pressure tested to 5000 psi and pressure was holding in 1 hour, indicating positive isolation has been established between tubing-annulus. From continuous annulus pressure monitoring, pressure in A annulus has been stable at ~40 psi for the last 8 months after sealant injection has been performed. Pressure activated sealant is proven as a reliable method to cure small leak in tubing. Since the sealant will only be hardened inside the leaking point, there will be no additional restriction in the tubing, thus Internal Diameter (ID) reduction will not be a concern for future well intervention operations. Pressure activated sealant could become one of the alternatives to cure tubing leaks, especially in the cases where tubing ID reduction is not favored.

Brain responses to watching food commercials compared with nonfood commercials: a meta-analysis on neuroimaging studies

Objective: This study aimed to identify and meta-analyse the neuroimaging data and hence synthesise a brain map showing the neural correlates of watching food commercials. Design: Published studies were retrieved and included into the analysis if they evaluated brain responses to food commercials with functional MRI and reported results based on whole-brain analysis in standard brain coordinates. Setting: No additional restriction was placed on the search, such as the publication year and age of participants. Participants: Seven papers that composed of a total of 442 participants fulfilled the inclusion criteria. All of them recruited children or adolescents. Results: Food commercials caused larger brain responses than nonfood counterparts in the cuneus on both hemispheres, which played a role in dietary self-control and modulation of food craving. Other brain regions involved in food commercials processing included the left culmen, left middle occipital gyrus and the right superior parietal lobule, which could be related to reward, emotional responses and habit formation. Conclusion: These neural correlates may help explain the food choice and eating behaviours of children and adolescents that might be relevant to the development of obesity.

The Incidence of Some Voting Paradoxes Under Domain Restrictions

Voting paradoxes have played an important role in the theory of voting. They typically say very little about the circumstances in which they are particularly likely or unlikely to occur. They are basically existence findings. In this article we study some well known voting paradoxes under the assumption that the underlying profiles are drawn from the Condorcet domain, i.e. a set of preference profiles where a Condorcet winner exists. The motivation for this restriction is the often stated assumption that profiles with a Condorcet winner are more likely than those without it. We further restrict the profiles by assuming that the starting point of our analysis is that the Condorcet winner coincides with the choice of the voting rule under scrutiny. The reason for making this additional restriction is that—intuitively—the outcomes that coincide with the Condorcet winner make those outcomes stable and, thus, presumably less vulnerable to various voting paradoxes. It will be seen that this is, indeed, the case for some voting rules and some voting paradoxes, but not for all of them.

Combined non-Orthodox Therapy in the Management of Treatment-Resistant Infections due to Helicobacter Pylori, Giardia Duodenalis and Microsporidium sp. In a Patient with Chronic Diarrhea, Wasting Synd

we resume a clinical case submitted to the Medical Microbiology Unit due to the complexity of etiological diagnosis and previous health issues of the patient, and with the additional restriction in the use of anti-infective treatments for a severe allergic reaction record.

Establishment of a Plasmid-Based Reverse Genetics System for the Cell Culture-Adapted Hepatitis E Virus Genotype 3c Strain 47832c

The hepatitis E virus (HEV) causes acute and chronic hepatitis in humans. Investigation of HEV replication is hampered by the lack of broadly applicable, efficient cell culture systems and tools for site-directed mutagenesis of HEV. The cell culture-adapted genotype 3c strain 47832c, which represents a typical genotype predominantly detected in Europe, has previously been used for several basic and applied research studies. Here, a plasmid-based reverse genetics system was developed for this strain, which efficiently rescued the infectious virus without the need for in vitro RNA transcription. The cotransfection of T7 RNA polymerase-expressing BSR/T7 cells with one plasmid encoding the full-length viral genome and two helper plasmids encoding vaccinia virus capping enzymes resulted in the production of infectious HEV, which could be serially passaged on A549/D3 cells. The parental and recombinant virus exhibited similar replication kinetics. A single point mutation creating an additional restriction enzyme site could be successfully introduced into the virus genome of progeny virus, indicating that the system is suitable for site-directed mutagenesis. This system is the first plasmid-based HEV reverse genetics system, as well as the first reverse genetics system for HEV genotype 3c, and should therefore be of broad use for basic and applied HEV research.

Search for binary code sequences with low autocorrelation sidelobes by the evolutionary method

Introduction: The parameters chosen for complex coded signals used in active radar systems of aircraft for detecting objects largelydetermines their qualitative characteristics and the possibility of covert operation. An important task in the design of such on-boardsystems is the formation of ensembles of pseudorandom-noise binary code sequences of a fixed length with predefined characteristics.Purpose: Search for PRN binary code sequences of a given length, optimal by the criterion of the minimum level of the sidelobes of theaperiodic autocorrelation function. Results: A procedure of search for binary code sequences with specified parameters based on theevolutionary approach is proposed. The minimum level of positive sidelobes of the autocorrelation function is used as a criterion forthe selection of code sequences. An additional restriction is imposed on the length of a substring of codes of the same character. Thepossibility of forming a representative array of sequences with the best ratio of the main peak of the aperiodic autocorrelation functionto its maximum positive sidelobe is shown on the example of 31-bit code sequences. An algorithm is proposed for generating a PRNseries of signals using the code sequences found. The Hamming distance is used as a measure of the difference between two binary codesequences in the series. The proposed approach is advantageous as compared to the well-known method of generating PRN signals basedon pseudorandom m-sequences. Practical relevance: The results obtained can be used in algorithms of airborne radar systems with ahigh range resolution to detect physical objects on the background of an underlying surface, for example, objects on the water surface.