A matter of time: Implicit acquisition of recursive sequence structures

A dominant hypothesis in empirical research on the evolution of language is the following: the fundamental difference between animal and human communication systems is captured by the distinction between regular and more complex non-regular grammars. Studies reporting successful artificial grammar learning of nested recursive structures and imaging studies of the same have methodological shortcomings since they typically allow explicit problem solving strategies and this has been shown to account for the learning effect in subsequent behavioral studies. The present study overcomes these shortcomings by using subtle violations of agreement structure in a preference classification task. In contrast to the studies conducted so far, we use an implicit learning paradigm, allowing the time needed for both abstraction processes and consolidation to take place. Our results demonstrate robust implicit learning of recursively embedded structures (context-free grammar) and recursive structures with cross-dependencies (context-sensitive grammar) in an artificial grammar learning task spanning 9 days. Keywords: Implicit artificial grammar learning; centre embedded; cross-dependency; implicit learning; context-sensitive grammar; context-free grammar; regular grammar; non-regular gramma

Marsh woundwort, Stachys palustris L. (Lamiaceae) : an overlooked food plant

The aim of this article is to study the geographical distribution and historical patterns of use of a little known root crop native to Europe-marsh woundwort Stachys palustris L. The species grows in wet grasslands and arable fields. It produces edible tubers. Both ethnographic literature and archival sources were searched. Seventeen reliable references concerning the consumption of S. palustris in southern and south-eastern Poland were found. The tubers were usually dried and powdered, and then added to soups or to bread dough. They were also eaten as raw snacks. The plant was used mainly during food shortages in spring, until the turn of the nineteenth and twentieth century, and later only as an occasional raw snack until the 1970s. Marsh woundwort was also eaten in western Ukraine (one reference). There are many references to the edibility of marsh woundwort in the eighteenth and nineteenth century European economic botany literature, particularly in Sweden and Great Britain. These publications tried to popularize the use of S. palustris as food. However, there is no firm evidence from these countries that marsh woundwort was used as food there. Marsh woundwort was also used, throughout northern and central Europe, as pig fodder and as a medicinal plant, particularly for healing wounds. Further studies on the nutritive value of this forgotten crop should be undertaken, particularly that there is little knowledge of the chemical composition of both marsh woundwort and its Asian relative Stachys affinis widely cultivated in China as a vegetable

Statistical Learning Theory for Control: A Finite Sample Perspective

This tutorial survey provides an overview of recent non-asymptotic advances in statistical learning theory as relevant to control and system identification. While there has been substantial progress across all areas of control, the theory is most well-developed when it comes to linear system identification and learning for the linear quadratic regulator, which are the focus of this manuscript. From a theoretical perspective, much of the labor underlying these advances has been in adapting tools from modern high-dimensional statistics and learning theory. While highly relevant to control theorists interested in integrating tools from machine learning, the foundational material has not always been easily accessible. To remedy this, we provide a self-contained presentation of the relevant material, outlining all the key ideas and the technical machinery that underpin recent results. We also present a number of open problems and future directions.Comment: Survey Paper, Submitted to Control Systems Magazine. Second version contains additional motivation for finite sample statistics and more detailed comparison with classical literatur

Multiple synchrotron self-Compton modeling of gamma-ray flares in 3C 279

The correlation often observed in blazars between optical-to-radio outbursts and gamma-ray flares suggests that the high-energy emission region shall be co-spatial with the radio knots, several parsecs away from the central engine. This would prevent the important contribution at high-energies from the Compton scattering of seed photons from the accretion disk and the broad-line region that is generally used to model the spectral energy distribution of low-frequency peaking blazars. While a pure synchrotron self-Compton model has so far failed to explain the observed gamma-ray emission of a flat spectrum radio quasar like 3C 279, the inclusion of the effect of multiple inverse-Compton scattering might solve the apparent paradox. Here, we present for the first time a physical, self-consistent SSC modeling of a series of shock-waves in the jet of 3C 279. We show that the analytic description of the high-energy emission from multiple inverse-Compton scatterings in the Klein-Nishina limit can fairly well account for the observed gamma-ray spectrum of 3C 279 in flaring states.Comment: 6 pages, 3 figures, proceedings of "Beamed and Unbeamed Gamma-rays from Galaxies", 11-15 April 2011, Finland. To be published in the Journal of Physics: Conference Serie

PHENIX measurement of jet properties and their modification in heavy-ion collisions

The properties of jets produced in p+p, d+Au and Au+Au collisions at sqrt{s_NN}=200 GeV are studied using the method of two particle correlations. The trigger particle is assumed to be a leading particle from a high p_T jet while the associated particle is assumed to come from either the same jet or the away jet. From the angular width and yield of the same and away side correlation peaks, the parameters characterizing the jet properties are extracted.Comment: 4 pages, 3 figures, contribution to the proceedings of the 17th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions (Quark Matter, Oakland, January 11-17, 2004). To appear in the proceedings (Journal of Physics G

Sputum quality and diagnostic performance of GeneXpert MTB/RIF among smear-negative adults with presumed tuberculosis in Uganda.

BackgroundIntroduction of GeneXpert MTB/RIF (Xpert) assay has constituted a major breakthrough for tuberculosis (TB) diagnostics. Several patient factors may influence diagnostic performance of Xpert including sputum quality.ObjectiveWe carried out a prospective, observational, cross-sectional study to determine the effect of sputum quality on diagnostic performance of Xpert among presumed TB patients in Uganda.MethodsWe collected clinical and demographic information and two sputum samples from participants. Staff recorded sputum quality and performed LED fluorescence microscopy and mycobacterial culture on each sample. If both smear examinations were negative, Xpert testing was performed. We calculated diagnostic yield, sensitivity, specificity, and other indicators for Xpert for each stratum of sputum quality in reference to a standard of mycobacterial culture.ResultsPatients with salivary sputum showed a trend towards a substantially higher proportion of samples that were Xpert-positive (54/286, 19%, 95% CI 15-24) compared with those with all other sputum sample types (221/1496, 15%, 95% CI 13-17). Blood-stained sputum produced the lowest sensitivity (28%; 95% CI 12-49) and salivary sputum the highest (66%; 95% CI 53-77). Specificity didn't vary meaningfully by sample types. Salivary sputum was significantly more sensitive than mucoid sputum (+13%, 95% CI +1 to +26), while blood-stained sputum was significantly less sensitive (-24%, 95% CI -42 to -5).ConclusionsOur findings demonstrate the need to exercise caution in collecting sputum for Xpert and in interpreting results because sputum quality may impact test yield and sensitivity. In particular, it may be wise to pursue additional testing should blood-stained sputum test negative while salivary sputum should be readily accepted for Xpert testing given its higher sensitivity and potentially higher yield than other sample types. These findings challenge conventional recommendations against collecting salivary sputum for TB diagnosis and could inform new standards for sputum quality

Risk of malignant melanoma in relation to drug intake, alcohol, smoking and hormonal factors.

In a population-based, matched case-control study from southern Sweden of 400 patients with a first diagnosis of malignant melanoma and 640 healthy control subjects aged 15-75 years, the association between commonly prescribed drugs, alcohol, smoking and malignant melanoma was evaluated. In addition, the relation between reproductive and hormonal factors and melanoma in women was studied. It was found that certain specific types of prescribed drugs, i.e. beta-blockers, hydralazines and benzodiazepines, may increase the risk of melanoma development. However, these associations were diminished, at least for benzodiazepines, after controlling for host factors. As these findings are unconfirmed, and may be due to chance or confounding, further studies are warranted. The risk of malignant melanoma was not influenced by alcohol consumption or smoking habits. Our results do not suggest an association between oral contraceptives and melanoma. Furthermore, reproductive factors were not independent risk factors for melanoma. However, increasing number of live births seemed to be protective (P for trend = 0.01). There is a need for further research to be able to draw firm conclusions on the relation between number of live births and melanoma. The results based on histopathological re-examinations and those based on tumour registry data were essentially the same

Risk of cutaneous malignant melanoma in relation to use of sunbeds: further evidence for UV-A carcinogenicity

In a population-based, matched, case–control study from southern Sweden of 571 patients with a first diagnosis of cutaneous malignant melanoma and 913 healthy controls aged 16–80 years, the association between sunbed use and malignant melanoma was evaluated. A total of 250 (44%) cases and 372 (41%) controls reported ever having used sunbeds. A significantly elevated odds ratio for developing malignant melanoma after regular exposure to sunbeds was found, adjusted for hair colour, raised naevi, skin type and number of sunburns (odds ratio (OR) 1.8, 95% confidence interval (CI) 1.2–2.7). A dose–response relationship between total number of sunbed uses and melanoma risk was only found up to the level of 250 times. The OR was higher in individuals younger than age 36 years (adjusted OR 8.1, 95% CI 1.3–49.5 for regular vs never use). The association seemed to be true only for subjects with black/dark brown or light brown hair and among females. Lesions of the extremities showed the strongest association of increased risk with sunbed use. An increased risk was related to commercial exposure and to exposure during the winter. The results substantiate the hypothesis that exposure to sunbeds might increase the risk of developing malignant melanoma. © 2000 Cancer Research Campaig