Divergent and narrower climatic niches characterize polyploid species of European primroses in Primula sect. Aleuritia

Aim It is hypothesized that the ecological niches of polyploids should be both distinct and broader than those of diploids - characteristics that might have allowed the successful colonization of open habitats by polyploids during the Pleistocene glacial cycles. Here, we test these hypotheses by quantifying and comparing the ecological niches and niche breadths of a group of European primroses. Location Europe. Methods We gathered georeferenced data of four related species in Primula sect. Aleuritia at different ploidy levels (diploid, tetraploid, hexaploid and octoploid) and used seven bioclimatic variables to quantify niche overlap between species by applying a series of univariate and multivariate analyses combined with modelling techniques. We also employed permutation-based tests to evaluate niche similarity between the four species. Niche breadth for each species was evaluated both in the multivariate environmental space and in geographical space. Results The four species differed significantly from each other in mono-dimensional comparisons of climatological variables and occupied distinct habitats in the multi-dimensional environmental space. The majority of the permutation-based tests either indicated that the four species differed significantly in their habitat preferences and ecological niches or did not support significant niche similarity. Furthermore, our results revealed narrower niche breadths and geographical ranges in species of P. sect. Aleuritia at higher ploidy levels. Main conclusions The detected ecological differentiation between the four species of P. sect. Aleuritia at different ploidy levels is consistent with the hypothesis that polyploids occupy distinct ecological niches that differ from those of their diploid relative. Contrary to expectations, we find that polyploid species of P. sect. Aleuritia occupy narrower environmental and geographical spaces than their diploid relative. These results on the ecological niches of closely related polyploid and diploid species highlight factors that potentially contribute to the evolution and distribution of polyploid species.

Acylation of chiral alcohols: a simple procedure for chiral GC analysis

The use of iodine as a catalyst and either acetic or trifluoroacetic acid as a derivatizing reagent for determining the enantiomeric composition of acyclic and cyclic aliphatic chiral alcohols was investigated. Optimal conditions were selected according to the molar ratio of alcohol to acid, the reaction time, and the reaction temperature. Afterwards, chiral stability of chiral carbons was studied. Although no isomerization was observed when acetic acid was used, partial isomerization was detected with the trifluoroacetic acid. A series of chiral alcohols of a widely varying structural type were then derivatized with acetic acid using the optimal conditions. The resolution of the enantiomeric esters and the free chiral alcohols was measured using a capillary gas chromatograph equipped with a CP Chirasil-DEX CB column. The best resolutions were obtained with 2-pentyl acetates (α = 3.00) and 2-hexyl acetates (α = 1.95). This method provides a very simple and efficient experimental workup procedure for analyzing chiral alcohols by chiral-phase GC.

Sherali-Adams Relaxations and Indistinguishability in Counting Logics

Two graphs with adjacency matrices $\mathbf{A}$ and $\mathbf{B}$ are isomorphic if there exists a permutation matrix $\mathbf{P}$ for which the identity $\mathbf{P}^{\mathrm{T}} \mathbf{A} \mathbf{P} = \mathbf{B}$ holds. Multiplying through by $\mathbf{P}$ and relaxing the permutation matrix to a doubly stochastic matrix leads to the linear programming relaxation known as fractional isomorphism. We show that the levels of the Sherali--Adams (SA) hierarchy of linear programming relaxations applied to fractional isomorphism interleave in power with the levels of a well-known color-refinement heuristic for graph isomorphism called the Weisfeiler--Lehman algorithm, or, equivalently, with the levels of indistinguishability in a logic with counting quantifiers and a bounded number of variables. This tight connection has quite striking consequences. For example, it follows immediately from a deep result of Grohe in the context of logics with counting quantifiers that a fixed number of levels of SA suffice to determine isomorphism of planar and minor-free graphs. We also offer applications in both finite model theory and polyhedral combinatorics. First, we show that certain properties of graphs, such as that of having a flow circulation of a prescribed value, are definable in the infinitary logic with counting with a bounded number of variables. Second, we exploit a lower bound construction due to Cai, Fürer, and Immerman in the context of counting logics to give simple explicit instances that show that the SA relaxations of the vertex-cover and cut polytopes do not reach their integer hulls for up to $\Omega(n)$ levels, where $n$ is the number of vertices in the graph.

A multi-contrast MRI study of microstructural brain damage in patients with mild cognitive impairment.

OBJECTIVES: The aim of this study was to investigate pathological mechanisms underlying brain tissue alterations in mild cognitive impairment (MCI) using multi-contrast 3 T magnetic resonance imaging (MRI). METHODS: Forty-two MCI patients and 77 healthy controls (HC) underwent T1/T2* relaxometry as well as Magnetization Transfer (MT) MRI. Between-groups comparisons in MRI metrics were performed using permutation-based tests. Using MRI data, a generalized linear model (GLM) was computed to predict clinical performance and a support-vector machine (SVM) classification was used to classify MCI and HC subjects. RESULTS: Multi-parametric MRI data showed microstructural brain alterations in MCI patients vs HC that might be interpreted as: (i) a broad loss of myelin/cellular proteins and tissue microstructure in the hippocampus (p ≤ 0.01) and global white matter (p < 0.05); and (ii) iron accumulation in the pallidus nucleus (p ≤ 0.05). MRI metrics accurately predicted memory and executive performances in patients (p ≤ 0.005). SVM classification reached an accuracy of 75% to separate MCI and HC, and performed best using both volumes and T1/T2*/MT metrics. CONCLUSION: Multi-contrast MRI appears to be a promising approach to infer pathophysiological mechanisms leading to brain tissue alterations in MCI. Likewise, parametric MRI data provide powerful correlates of cognitive deficits and improve automatic disease classification based on morphometric features.

Total synthesis of entecavir

Entecavir (BMS-200475) was synthesized from 4-trimethylsilyl-3-butyn-2-one and acrolein. The key features of its preparation are: (i) a stereoselective boron-aldol reaction to afford the acyclic carbon skeleton of the methylenecylopentane moiety; (ii) its cyclization by a Cp2TiCl-catalyzed intramolecular radical addition of an epoxide to an alkyne; and (iii) the coupling with a purine derivative by a Mitsunobu reaction.

Weakened functional connectivity in patients with psychogenic non-epileptic seizures (PNES) converges on basal ganglia.

BACKGROUND: Psychogenic non-epileptic seizures (PNES) are involuntary paroxysmal events that are unaccompanied by epileptiform EEG discharges. We hypothesised that PNES are a disorder of distributed brain networks resulting from their functional disconnection.The disconnection may underlie a dissociation mechanism that weakens the influence of unconsciously presented traumatising information but exerts maladaptive effects leading to episodic failures of behavioural control manifested by psychogenic 'seizures'. METHODS: To test this hypothesis, we compared functional connectivity (FC) derived from resting state high-density EEGs of 18 patients with PNES and 18 age-matched and gender-matched controls. To this end, the EEGs were transformed into source space using the local autoregressive average inverse solution. FC was estimated with a multivariate measure of lagged synchronisation in the θ, α and β frequency bands for 66 brain sites clustered into 18 regions. A multiple comparison permutation test was applied to deduce significant between-group differences in inter-regional and intraregional FC. RESULTS: The significant effect of PNES-a decrease in lagged FC between the basal ganglia and limbic, prefrontal, temporal, parietal and occipital regions-was found in the α band. CONCLUSION: We believe that this finding reveals a possible neurobiological substrate of PNES, which explains both attenuation of the effect of potentially disturbing mental representations and the occurrence of PNES episodes. By improving understanding of the aetiology of this condition, our results suggest a potential refinement of diagnostic criteria and management principles.

Agentes complexantes: podante, coronante e criptante classificação e nomenclatura

The scientific and practical interest in crown ethers as complexing agents for actions as well as for anions and neutral low molecular species is undeniable. New molecules with crown ether properties are constantly synthesized and new application discovered. This paper presents classification and nomenclature of the classical oligoethers (crown ethers): monocyclic coronands; oligocyclic spherical cryptands; and acyclic podands.

Hückel and Möbius annulenes: relationships between their Hückel-level orbitals and their Hückel-level energies

The problem of convenient access to quantitative Hückel-level descriptions of Möbius and Hückel annulenes for undergraduate lectures about aromaticity is discussed. Frost circle, Zimmerman circle, double circle and Langler semicircular mnemonics are described. The relationship between spectra (complete sets of secular equation roots) for an isoconjugate pair of Hückel and Möbius annulenes and the corresponding acyclic polyene with one less carbon is fully developed. In addition to providing an alternative path to exact spectrum roots, this relationship provides immediate access to almost half of the eigenfunctions for an isoconjugate annulene pair. The remaining eigenfunctions may be obtained very easily.

A structural bridge between alternant and non-alternant hydrocarbons

A simple set of trimethylene-substituted even, fully-pi-bonded, non-alternant monocycles is shown to have several key features in common with acyclic, even alternant polyenes at the Hückel level. These non-alternant molecules provide a bridge between alternant and non-alternant hydrocarbons. This topic might serve as a useful addition to Hückel theory courses targeted at senior undergraduate students.

A Cartan-Eilenberg approach to Homotopical Algebra

In this paper we propose an approach to homotopical algebra where the basic ingredient is a category with two classes of distinguished morphisms: strong and weak equivalences. These data determine the cofibrant objects by an extension property analogous to the classical lifting property of projective modules. We define a Cartan-Eilenberg category as a category with strong and weak equivalences such that there is an equivalence of categories between its localisation with respect to weak equivalences and the relative localisation of the subcategory of cofibrant objects with respect to strong equivalences. This equivalence of categories allows us to extend the classical theory of derived additive functors to this non additive setting. The main examples include Quillen model categories and categories of functors defined on a category endowed with a cotriple (comonad) and taking values on a category of complexes of an abelian category. In the latter case there are examples in which the class of strong equivalences is not determined by a homotopy relation. Among other applications of our theory, we establish a very general acyclic models theorem.

Óleos voláteis de espécies de Myrcia nativas do Rio Grande do Sul

Essential oils from M. richardiana, M. arborescens, M. selloi, M. oligantha, M. rostrata, M. lajeana, M. obtecta, M. pubipetala and M. hatschbachii were obtained by hydrodistillation and analyzed by GC and GC/MS. Sixty-seven compounds have been identified ranging from 90-99% of the oil contents. All analyzed species were rich in cyclic sesquiterpenes (66-99%), mainly those from the cadinane, caryophyllane and germacrane cyclization pathway, among them b-caryophyllene, germacrene D, bicyclogermacrene, d-cadinene, spathulenol, caryophyllene oxide, globulol and a-cadinol. The acyclic sesquiterpene series was well represented by M. lajeana (32.1%), with 25,3% of (E)-nerolidyl acetate.

Síntese de novas amidas graxas a partir da aminólise de ésteres metílicos

Recent biochemical and pharmacological studies have led to the characterization of different fatty acid amides as a new family of biologically active lipids. Here, we describe the synthesis of new amides from C16:0, 18:0, 18:1 and 18:1, OH fatty acids (FFA) families with cyclic and acyclic amines and demonstrate for the first time that these compounds produce citotoxic effects. Application of this method to the synthesis of fatty acid amides was performed using the esters aminolysis as a key step and various carboxylic amides were prepared in good yield from fatty acid methyl esters (FAMEs).

Evaluating multidimensional visualization techniques in data mining tasks

Visual data mining (VDM) tools employ information visualization techniques in order to represent large amounts of high-dimensional data graphically and to involve the user in exploring data at different levels of detail. The users are looking for outliers, patterns and models – in the form of clusters, classes, trends, and relationships – in different categories of data, i.e., financial, business information, etc. The focus of this thesis is the evaluation of multidimensional visualization techniques, especially from the business user’s perspective. We address three research problems. The first problem is the evaluation of projection-based visualizations with respect to their effectiveness in preserving the original distances between data points and the clustering structure of the data. In this respect, we propose the use of existing clustering validity measures. We illustrate their usefulness in evaluating five visualization techniques: Principal Components Analysis (PCA), Sammon’s Mapping, Self-Organizing Map (SOM), Radial Coordinate Visualization and Star Coordinates. The second problem is concerned with evaluating different visualization techniques as to their effectiveness in visual data mining of business data. For this purpose, we propose an inquiry evaluation technique and conduct the evaluation of nine visualization techniques. The visualizations under evaluation are Multiple Line Graphs, Permutation Matrix, Survey Plot, Scatter Plot Matrix, Parallel Coordinates, Treemap, PCA, Sammon’s Mapping and the SOM. The third problem is the evaluation of quality of use of VDM tools. We provide a conceptual framework for evaluating the quality of use of VDM tools and apply it to the evaluation of the SOM. In the evaluation, we use an inquiry technique for which we developed a questionnaire based on the proposed framework. The contributions of the thesis consist of three new evaluation techniques and the results obtained by applying these evaluation techniques. The thesis provides a systematic approach to evaluation of various visualization techniques. In this respect, first, we performed and described the evaluations in a systematic way, highlighting the evaluation activities, and their inputs and outputs. Secondly, we integrated the evaluation studies in the broad framework of usability evaluation. The results of the evaluations are intended to help developers and researchers of visualization systems to select appropriate visualization techniques in specific situations. The results of the evaluations also contribute to the understanding of the strengths and limitations of the visualization techniques evaluated and further to the improvement of these techniques.

Efficacy of geraniol but not of β-ionone or their combination for the chemoprevention of rat colon carcinogenesis

β-ionone (βI), a cyclic isoprenoid, and geraniol (GO), an acyclic monoterpene, represent a promising class of dietary chemopreventive agents against cancer, whose combination could result in synergistic anticarcinogenic effects. The chemopreventive activities of βI and GO were evaluated individually or in combination during colon carcinogenesis induced by dimethylhydrazine in 48 3-week-old male Wistar rats (12 per group) weighing 40-50 g. Animals were treated for 9 consecutive weeks with βI (16 mg/100 g body weight), GO (25 mg/100 g body weight), βI combined with GO or corn oil (control). Number of total aberrant crypt foci (ACF) and of ACF ≥4 crypts in the distal colon was significantly lower in the GO group (66 ± 13 and 9 ± 2, respectively) compared to control (102 ± 9 and 17 ± 3) and without differences in the βI (91 ± 11 and 14 ± 3) and βI+GO groups (96 ± 5 and 19 ± 2). Apoptosis level, identified by classical apoptosis morphological criteria, in the distal colon was significantly higher in the GO group (1.64 ± 0.06 apoptotic cells/mm²) compared to control (0.91 ± 0.07 apoptotic cells/mm²). The GO group presented a 0.7-fold reduction in Bcl-2 protein expression (Western blot) compared to control. Colonic mucosa concentrations of βI and GO (gas chromatography/mass spectrometry) were higher in the βI and GO groups, respectively, compared to the control and βI+GO groups. Therefore, GO, but not βI, represents a potential chemopreventive agent in colon carcinogenesis. Surprisingly, the combination of isoprenoids does not represent an efficient chemopreventive strategy.

Recueil sur les Monnaies.

Contient : « C'est l'avaluation des monnoyes d'or et d'argent estrangères, selon les poix et essay qui en ont esté faictz par nous, Jean L'HUILLIER, seigneur de Boulancourt, président en la Chambre des Comptes, et Jean GROLLIER, seigneur d'Aguisy, trésorier de France, appelez avecques nous maistres Alexandre DE LA TORRETTE, président en la Court des Monnoies, Guillaume MARILLAC, maistre ordinaire en la Chambre desdictz Comptes, Charles PREVOST, auditeur en icelle Chambre, Claude MARCEL, essayeur général desdictes monnoies, et Guillaume LE GRAS, marchant, bourgeois à Paris, suivant les lettres closes du roy » François II ; « faict et arresté à Paris, le XIIIe jour d'avril, l'an 1559, avant Pasques » [1560] ; orig. signé (f. 28) de « Luillier », « Grolier », « de La Tourrete », « Marillac », « Le Prevost », « Marcel » et « Legras » ; Traité sur les monnaies, copie du XVIIe siècle : « Les monoyes ont esté establies non seulement pour éviter les incomoditez de la permutation... »