469 research outputs found

    Does the catechol-O-methyltransferase (COMT) Val158Met human polymorphism in influence procrastination?

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    Genetic studies are enlightening how the expression of several genes influences neuronal activity and all facets of human normal and abnormal behaviour. Among these, a growing body of information shows that a few key genes regulating activity of central neurotransmitters have specific roles in cognitive and/or emotional processes, as ‘procrastination’. We investigated the association of the 5-HTTLPR and COMT Val158Met polymorphisms with students’ procrastination in an academic writing task. Results: showed no relationship between procrastination and the 5-HTT polymorphism but they revealed an association with the COMT Val158Met one. Particularly, the presence of the Met158 allele was found to be significantly associated with the tendency to initiate and complete the assigned task. We hypothesize that the role of central monoamines and of dopamine already identified in impulsive behaviour, extends to procrastination. Since the 158Met allele provides neurons with significantly higher basal dopamine levels when compared to the 158Val allele, our observation suggests that under normal conditions the 158Met allele provides carriers with increased inhibitory control, resulting in an increased tendency to adhere to a planned schedule and therefore reducing procrastination. On the other hand, the Val158 allele may result more effective in increasing carriers’ performances under stress conditions, namely when the schedule deadline is approaching, and dopamine release is increased. This would result in a higher tendency to procrastinate. This hypothesis can readily be tested by applying the experimental approach here employed to various samples of subjects belonging to different categories and extending the analysis to other putative neuron-expressed gene

    Virtual Environment for Next Generation Sequencing Analysis

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    Next Generation Sequencing technology, on the one hand, allows a more accurate analysis, and, on the other hand, increases the amount of data to process. A new protocol for sequencing the messenger RNA in a cell, known as RNA- Seq, generates millions of short sequence fragments in a single run. These fragments, or reads, can be used to measure levels of gene expression and to identify novel splice variants of genes. The proposed solution is a distributed architecture consisting of a Grid Environment and a Virtual Grid Environment, in order to reduce processing time by making the system scalable and flexibl

    A Cloud Infrastructure for Optimization of a Massive Parallel Sequencing Workflow

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    Massive Parallel Sequencing is a term used to describe several revolutionary approaches to DNA sequencing, the so-called Next Generation Sequencing technologies. These technologies generate millions of short sequence fragments in a single run and can be used to measure levels of gene expression and to identify novel splice variants of genes allowing more accurate analysis. The proposed solution provides novelty on two fields, firstly an optimization of the read mapping algorithm has been designed, in order to parallelize processes, secondly an implementation of an architecture that consists of a Grid platform, composed of physical nodes, a Virtual platform, composed of virtual nodes set up on demand, and a scheduler that allows to integrate the two platform

    Optimizing Splicing Junction Detection in Next Generation Sequencing Data on a Virtual-GRID Infrastructure

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    The new protocol for sequencing the messenger RNA in a cell, named RNA-seq produce millions of short sequence fragments. Next Generation Sequencing technology allows more accurate analysis but increase needs in term of computational resources. This paper describes the optimization of a RNA-seq analysis pipeline devoted to splicing variants detection, aimed at reducing computation time and providing a multi-user/multisample environment. This work brings two main contributions. First, we optimized a well-known algorithm called TopHat by parallelizing some sequential mapping steps. Second, we designed and implemented a hybrid virtual GRID infrastructure allowing to efficiently execute multiple instances of TopHat running on different samples or on behalf of different users, thus optimizing the overall execution time and enabling a flexible multi-user environmen

    Markov chain approximations to stochastic differential equations by recombination on lattice trees

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    We revisit the classical problem of approximating a stochastic differential equation by a discrete-time and discrete-space Markov chain. Our construction iterates Caratheodory's theorem over time to match the moments of the increments locally. This allows to construct a Markov chain with a sparse transition matrix where the number of attainable states grows at most polynomially as time increases. Moreover, the MC evolves on a tree whose nodes lie on a "universal lattice" in the sense that an arbitrary number of different SDEs can be approximated on the same tree. The construction is not tailored to specific models, we discuss both the case of uni-variate and multi-variate case SDEs, and provide an implementation and numerical experiments

    Grid-free computation of probabilistic safety with Malliavin Calculus

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    This work concerns continuous-time, continuous-space stochastic dynamical systems described by stochastic differential equations (SDE). It presents a new approach to compute probabilistic safety regions, namely sets of initial conditions of the SDE associated to trajectories that are safe with a probability larger than a given threshold. The approach introduces a functional that is minimised at the border of the probabilistic safety region, then solves an optimisation problem using techniques from Malliavin Calculus, which computes such region. Unlike existing results in the literature, the new approach allows one to compute probabilistic safety regions without gridding the state space of the SDE

    Carathéodory sampling for stochastic gradient descent

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    Many problems require to optimize empirical risk functions over large data sets. Gradient descent methods that calculate the full gradient in every descent step do not scale to such datasets. Various flavours of Stochastic Gradient Descent (SGD) replace the expensive summation that computes the full gradient by approximating it with a small sum over a randomly selected subsample of the data set that in turn suffers from a high variance. We present a different approach that is inspired by classical results of Tchakaloff and Carathéodory about measure reduction. These results allow to replace an empirical measure with another, carefully constructed probability measure that has a much smaller support, but can preserve certain statistics such as the expected gradient. To turn this into scalable algorithms we firstly, adaptively select the descent steps where the measure reduction is carried out; secondly, we combine this with Block Coordinate Descent so that measure reduction can be done very cheaply. This makes the resulting methods scalable to high-dimensional spaces. Finally, we provide an experimental validation and comparison

    Innovative algorithms and data structures for signal treatment applied to ISO/IEC/IEEE 21451 smart transducers

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    2014 - 2015Technologies and, in particular sensors, permeate more and more application sectors. From energy management, to the factories one, to houses, environments, infrastructure, and building monitoring, to healthcare and traceability systems, sensors are more and more widespread in our daily life. In the growing context of the Internet of Things capabilities to acquire magnitudes of interest, to elaborate and to communicate data is required to these technologies. These capabilities of acquisition, elaboration, and communication can be integrated on a unique device, a smart sensor, which integrates the sensible element with a simple programmable logic device, capable of managing elaboration and communication. An efficient implementation of communication is required to these technologies, in order to better exploit the available bandwidth, minimizing energy consumption. Moreover, these devices have to be easily interchangeable (plug and play) in such a way that they could be easily usable. Nowadays, smart sensors available on the market reveal several problems such as programming complexity, for which depth knowledge is required, and limited software porting capability. The family of standards IEEE 1451 is written with the aim to define a set of common communication interfaces. These documents come from the Institute of Electric and Electronic Engineers (IEEE) with the aim to create a standard interface which allows devices interoperability produced from different manufacturers, but it is not concerned with problems related to bandwidth, management, elaboration and programming. For this family of standards, now under review, it is expected a further development, with the aim to renew applicable standards, and to add new layers of standardization. The draft of the ISO/IEC/IEEE 21451.001 proposes to solve problems related to the bandwidth and the elaboration management, relocating a part of processing in the point of acquisition, taking advantage of elaboration capabilities of smart sensors. This proposal is based on a Real Time Segmentation and Labeling algorithm, a new sampling technique, which allows to reduce the high number of samples to be transferred, with the same information content. This algorithm returns a data structure, according to which the draft expects two elaboration layers: a first layer, in order to elaborate basic information of the signal processing, and a second layer, for more complex elaboration. [edited by author]XIV n.s

    Sonoelastography in the diagnosis of tendinopathies: An added value

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    BACKGROUND: sonoelastography helps in the detection of abnormalities not yet evident on B-mode exam. METHODS: in this observational study, we report a collection of cases of symptomatic patients without alterations at ultrasound imaging but with evidence of pathological findings at sonoelastography. Patients, with clinical history suggestive for tendinopathies or surgically treated, and negative at the ultrasound exam, were submitted to sonoelastography. Out of 846, 632 patients with positive ultrasound exam were excluded. Sonoelastography was therefore performed in the remaining 214. RESULTS: the examination was positive in 168 cases: 78 patients were affected with shoulder diseases, while elbow pathology was observed in 31 subjects; patellar, Achilles and plantar fascia disorders were reported in 19, 27, and 13 patients, respectively. CONCLUSION: sonoelastography can reveal tendon abnormalities of clinical relevance in a high percentage of cases, where the ultrasound exam was negative, making the method a complementary tool to ultrasound evaluation

    Successful role of adjuvant radiotherapy in a rare case of tracheal inflammatory myofibroblastic tumor: a case report

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    BACKGROUND:: Inflammatory myofibroblastic tumor (IMT) is a rare benign cancer that can express a more aggressive phenotype related to the genetic mutation of the anaplastic lymphoma kinase receptor (ALK). Involvement of trachea is extremely rare and due to the clinical and radiologic nonspecificity, the definitive diagnosis is based on the histologic evaluation of tissue specimens. Total surgical excision is curative and chemotherapy or radiotherapy has been employed in the treatment of unresectable tumors or as adjuvant therapies. CASE PRESENTATION:: The case described here is being reported because of the rare tracheal location and the atypical treatment approach used for an ALK-positive IMT. A 7-week pregnant woman voluntary interrupted pregnancy and underwent total surgical excision that resulted to have close margins. Although ALK-positive expression indicated the use of ALK inhibitors, she refused any type of adjuvant therapy that could affect ovarian function. Thus, 3D conformational external beam radiotherapy was performed with a daily dose of 180 cGy, 5 times per week, up to 45 Gy at the level of trachea. A total of 62 months of follow-up showed and no signs of disease recurrence or late radiation therapy-related toxicity. CONCLUSIONS: This report describes an extremely rare case of a tracheal IMT, underlying the key role of radiotherapy as adjuvant treatment able to definitively cure IMT, limiting systemic chemotherapy-related toxicity
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