Multidimensional random motion with uniformly distributed changes of direction and Erlang steps

In this paper we study transport processes in Rⁿ, n≥1, having non-exponential distributed sojourn times or non-Markovian step durations. We use the idea that the probabilistic properties of a random vector are completely determined by those of its projection on a fixed line, and using this idea we avoid many of the difficulties appearing in the analysis of these problems in higher dimensions. As a particular case, we find the probability density function in three dimensions for 2-Erlang distributed sojourn times.Дослiджено процеси переносу в Rⁿ, n≥1, що мають неекспоненцiально розподiлений час перебування або немарковську тривалiсть крокiв. Використано iдею про те, що ймовiрнiснi властивостi випадкового вектора цiлком визначаються такими самими властивостями його проекцiй на фiксовану пряму. Цей пiдхiд дозволив уникнути багатьох складностей, що з’являються при дослiдженнi цих проблем у вимiрностях вищого порядку. Як окремий випадок, знайдено функцiю щiльностi ймовiрностi у тривимiрному випадку для часу перебування з 2-розподiлом Ерланга

Solution of systems of partial differential equations by using properties of monogenic functions on commutative algebras

Some systems of differential equations with partial derivatives are studied by using the properties of Gateaux differentiable functions on commutative algebras. The connection between solutions of systems of partial differential equations and components of monogenic functions on the corresponding commutative algebras is shown.We also give some examples of systems of partial differential equations and find their solutions

Brain fog in neuropathic postural tachycardia syndrome may be associated with autonomic hyperarousal and improves after water drinking.

Brain fog is a common and highly disturbing symptom for patients with neuropathic postural tachycardia syndrome (POTS). Cognitive deficits have been measured exclusively in the upright body position and mainly comprised impairments of higher cognitive functions. The cause of brain fog is still unclear today. This study aimed to investigate whether increased autonomic activation might be an underlying mechanism for the occurrence of brain fog in neuropathic POTS. We therefore investigated cognitive function in patients with neuropathic POTS and a healthy control group depending on body position and in relation to catecholamine release as a sensitive indicator of acute stress. The second aim was to test the effect of water intake on cardiovascular regulation, orthostatic symptoms, cognitive function and catecholamine release. Thirteen patients with neuropathic POTS and 15 healthy control subjects were included. All participants completed a total of four rounds of cognitive testing: two before and two after the intake of 500 ml still water, each first in the supine position and then during head-up tilt. At the end of each cognitive test, a blood sample was collected for determination of plasma catecholamines. After each head-up tilt phase participants were asked to rate their current symptoms on a visual analogue scale. Working memory performance in the upright body position was impaired in patients, which was associated with self-reported symptom severity. Patients had elevated plasma norepinephrine independent of body position and water intake that increased excessively in the upright body position. The excessive increase of plasma norepinephrine was related to heart rate and symptom severity. Water intake in patients decreased norepinephrine concentrations and heart rate, and improved symptoms as well as cognitive performance. Brain fog and symptom severity in neuropathic POTS are paralleled by an excessive norepinephrine secretion. Bolus water drinking down-regulates norepinephrine secretion and improves general symptom severity including brain fog

Solutions of some partial differential equations with variable coefficients by properties of monogenic functions

In this paper we study some partial differential equations by using properties of Gateaux differentiable functions on commutative algebra. It is proved that components of differentiable functions satisfy some partial differential equations with coefficients related with properties of bases of subspaces of the corresponding algebra

Variabilidad en la presentación del Síndrome de Brown-McLean

Case report: We report two aphakic patients with Brown-McLean syndrome. Discussion: One patient was affected by Marfan syndrome, after having undergone lens subluxation surgery and aphakia 23 years previously. The other patient was aphakic due to cataract surgery with complications three years before. Our cases demonstrate that this syndrome can show a variety of clinical characteristics, but peripheral corneal edema is always present. A full understanding of the clinical signs of presentation is of great importance in order to detect this syndrom

Bayesian nonparametric models for name disambiguation and supervised learning

This thesis presents new Bayesian nonparametric models and approaches for their development, for the problems of name disambiguation and supervised learning. Bayesian nonparametric methods form an increasingly popular approach for solving problems that demand a high amount of model flexibility. However, this field is relatively new, and there are many areas that need further investigation. Previous work on Bayesian nonparametrics has neither fully explored the problems of entity disambiguation and supervised learning nor the advantages of nested hierarchical models. Entity disambiguation is a widely encountered problem where different references need to be linked to a real underlying entity. This problem is often unsupervised as there is no previously known information about the entities. Further to this, effective use of Bayesian nonparametrics offer a new approach to tackling supervised problems, which are frequently encountered. The main original contribution of this thesis is a set of new structured Dirichlet process mixture models for name disambiguation and supervised learning that can also have a wide range of applications. These models use techniques from Bayesian statistics, including hierarchical and nested Dirichlet processes, generalised linear models, Markov chain Monte Carlo methods and optimisation techniques such as BFGS. The new models have tangible advantages over existing methods in the field as shown with experiments on real-world datasets including citation databases and classification and regression datasets. I develop the unsupervised author-topic space model for author disambiguation that uses free-text to perform disambiguation unlike traditional author disambiguation approaches. The model incorporates a name variant model that is based on a nonparametric Dirichlet language model. The model handles both novel unseen name variants and can model the unknown authors of the text of the documents. Through this, the model can disambiguate authors with no prior knowledge of the number of true authors in the dataset. In addition, it can do this when the authors have identical names. I use a model for nesting Dirichlet processes named the hybrid NDP-HDP. This model allows Dirichlet processes to be clustered together and adds an additional level of structure to the hierarchical Dirichlet process. I also develop a new hierarchical extension to the hybrid NDP-HDP. I develop this model into the grouped author-topic model for the entity disambiguation task. The grouped author-topic model uses clusters to model the co-occurrence of entities in documents, which can be interpreted as research groups. Since this model does not require entities to be linked to specific words in a document, it overcomes the problems of some existing author-topic models. The model incorporates a new method for modelling name variants, so that domain-specific name variant models can be used. Lastly, I develop extensions to supervised latent Dirichlet allocation, a type of supervised topic model. The keyword-supervised LDA model predicts document responses more accurately by modelling the effect of individual words and their contexts directly. The supervised HDP model has more model flexibility by using Bayesian nonparametrics for supervised learning. These models are evaluated on a number of classification and regression problems, and the results show that they outperform existing supervised topic modelling approaches. The models can also be extended to use similar information to the previous models, incorporating additional information such as entities and document titles to improve prediction

Substrate Flexibility of a Mutated Acyltransferase Domain and Implications for Polyketide Biosynthesis

SummaryPolyketides are natural products frequently used for the treatment of various diseases, but their structural complexity hinders efficient derivatization. In this context, we recently introduced enzyme-directed mutasynthesis to incorporate non-native extender units into the biosynthesis of erythromycin. Modeling and mutagenesis studies led to the discovery of a variant of an acyltransferase domain in the erythromycin polyketide synthase capable of accepting a propargylated substrate. Here, we extend molecular rationalization of enzyme-substrate interactions through modeling, to investigate the incorporation of substrates with different degrees of saturation of the malonic acid side chain. This allowed the engineered biosynthesis of new erythromycin derivatives and the introduction of additional mutations into the AT domain for a further shift of the enzyme's substrate scope. Our approach yields non-native polyketide structures with functional groups that will simplify future derivatization approaches, and provides a blueprint for the engineering of AT domains to achieve efficient polyketide synthase diversification

Strategies and options for increasing and sustaining fisheries and aquaculture production to benefit poorer households in Asia [PDF in letter standard]

The last three decades have wi tnessed dramatic changes in the structure of supply and demand for fish, especially in Asia. This WorldFish research study sponsored by the Asian Development Bank focussed on nine developing countries û Bangladesh, China, India, Indonesia, Malaysia, the Philippines, Sri Lanka, Thailand, and Vietnam, all active players in the transformation of global fish supply and demand. The study, broken into five components and reported here, considered: 1) the profile of key aquaculture technologies and fishing practices; 2) analysis of policies, institutions and support services; 3) socioeconomic profile of major stakeholders in the fisheries sector; 4) projections of fish demand and supply in the nine Asian countries; and 5) formulation of national action plans based on the findings and recommendations of the study.Research, Fisheries, Economic analysis, Aquaculture, Fish consumption, Trade, Policies, Socioeconomic aspects, Technology, Fishery products, Asia, China, People's Rep., Bangladesh, India, Indonesia, Malaysia, Philippines, Malaysia, Sri Lanka, Thailand, Vietnam,

The human eye-movement response to maintained surface galvanic vestibular stimulation

Contains fulltext : 141356.pdf (publisher's version ) (Closed access