156 research outputs found

    Espécies do cerrado com potencial para recuperação de áreas degradadas, Gurupi (TO)

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    A cobertura vegetal do Bioma Cerrado vem sendo substituída em decorrência de atividades antrópicas, necessitando de técnicas e estratégias para a recuperação das áreas degradadas. Este trabalho objetivou identificar e recomendar espécies arbustivo-arbóreas da flora de uma área de cerrado sensu stricto, estado do Tocantins, para auxiliar no manejo adequado de áreas similares. Foram instaladas, em área de cerrado sensu stricto da fazenda experimental da UFT, três parcelas amostrais na área experimental, com dimensões de 20 × 50 m cada uma, totalizando 3.000 m². Todos os indivíduos arbustivo-arbóreos com circunferência maior ou igual a 10 cm, a 1,30 cm do solo (CAP), foram amostrados. A fim de obter os parâmetros fitossociológicos, foi utilizado o programa Fitopac versão 2.1. Determinou-se a forma de vida de acordo com a classificação de Raunkiaer para espécies amostradas e identificadas em nível específico. Foram identificados 598 indivíduos, 78 espécies e 39 famílias. A forma de vida predominante entre as espécies identificadas na área de cerrado foram as Fanerófitas. As famílias que apresentaram maior número de indivíduos foram: Vochysiaceae, Myrtaceae, Burseraceae, Malpighiaceae e Fabaceae. As espécies que apresentaram maior valor de cobertura foram Protium heptaphyllum, Myrcia splendens, Qualea multiflora, Tapirira guianensis, Magonia pubescens Copaifera langsdorffii Desf, Psidium guineense Sw, Cordia glabrata (Mart.) A.DC, inferindo que essas espécies possuem grande potencial para áreas degradas do Bioma Cerrado

    Slits Are Chemorepellents Endogenous to Hypothalamus and Steer Thalamocortical Axons into Ventral Telencephalon

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    Thalamocortical axons (TCAs) originate in dorsal thalamus, extend ventrally along the lateral thalamic surface, and as they approach hypothalamus make a lateral turn into ventral telencephalon. In vitro studies show that hypothalamus releases a chemorepellent for TCAs, and analyses of knockout mice indicate that Slit chemorepellents and their receptor Robo2 influence TCA pathfinding. We show that Slit chemorepellents are the hypothalamic chemorepellent and act through Robos to steer TCAs into ventral telencephalon. During TCA pathfinding, Slit1 and Slit2 are expressed in hypothalamus and ventral thalamus and Robo1 and Robo2 are expressed in dorsal thalamus. In collagen gel cocultures of dorsal thalamus and Slit2-expressing cells, axon number and length are decreased on the explant side facing Slit2-expressing cells, overall axon outgrowth is diminished, and axons turn away from the Slit2-expressing cells. Thus, Slit2 is an inhibitor and chemorepellent for dorsal thalamic axons. Collagen gel cocultures of dorsal thalamus with sections of live diencephalon, with and without the hypothalamus portion overlaid with Robo2-fc-expressing cells to block Slit function, identify Slits as the hypothalamic chemorepellent. Thus, Slits are chemorepellents for TCAs endogenous to hypothalamus and steer TCAs from diencephalon into ventral telencephalon, a critical pathfinding event defective in Slit and Robo2 mutant mice

    The Integrated system for Natural Capital Accounting (INCA) in Europe: twelve lessons learned from empirical ecosystem service accounting

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    Open Access Article; Published online: 16 Sep 2022The Integrated system for Natural Capital Accounting (INCA) was developed and supported by the European Commission to test and implement the System of integrated Environmental and Economic Accounting – Ecosystem Accounting (SEEA EA). Through the compilation of nine Ecosystem Services (ES) accounts, INCA can make available to any interested ecosystem accountant a number of lessons learned. Amongst the conceptual lessons learned, we can mention: (i) for accounting purposes, ES should be clustered according to the existence (or not) of a sustainability threshold; (ii) the assessment of ES flow results from the interaction of an ES potential and an ES demand; (iii) the ES demand can be spatially identified, but for an overarching environmental target, this is not possible; ES potential and ES demand could mis-match; (iv) because the demand remains unsatisfied; (v) because the ES is used above its sustainability threshold or (vi) because part of the potential flow is missed; (vii) there can be a cause-and-effect relationship between ecosystem condition and ES flow; (viii) ES accounts can complement the SEEA Central Framework accounts without overlapping or double counting. Amongst the methodological lessons learned, we can mention: (ix) already exiting ES assessments do not directly provide ES accounts, but will likely need some additional processing; (x) ES cannot be defined by default as intermediate; (xi) the ES remaining within ecosystems cannot be reported as final; (xii) the assessment and accounting of ES can be undertaken throughout a fast track approach or more demanding modelling procedures

    An MBO scheme for minimizing the graph Ohta-Kawasaki functional

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    We study a graph based version of the Ohta-Kawasaki functional, which was originally introduced in a continuum setting to model pattern formation in diblock copolymer melts and has been studied extensively as a paradigmatic example of a variational model for pattern formation. Graph based problems inspired by partial differential equations (PDEs) and varational methods have been the subject of many recent papers in the mathematical literature, because of their applications in areas such as image processing and data classification. This paper extends the area of PDE inspired graph based problems to pattern forming models, while continuing in the tradition of recent papers in the field. We introduce a mass conserving Merriman-Bence-Osher (MBO) scheme for minimizing the graph Ohta-Kawasaki functional with a mass constraint. We present three main results: (1) the Lyapunov functionals associated with this MBO scheme Γ-converge to the Ohta-Kawasaki functional (which includes the standard graph based MBO scheme and total variation as a special case); (2) there is a class of graphs on which the Ohta-Kawasaki MBO scheme corresponds to a standard MBO scheme on a transformed graph and for which generalized comparison principles hold; (3) this MBO scheme allows for the numerical computation of (approximate) minimizers of the graph Ohta-Kawasaki functional with a mass constraint

    Language impairment in a case of a complex chromosomal rearrangement with a breakpoint downstream of FOXP2

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    BACKGROUND: We report on a young female, who presents with a severe speech and language disorder and a balanced de novo complex chromosomal rearrangement, likely to have resulted from a chromosome 7 pericentromeric inversion, followed by a chromosome 7 and 11 translocation. RESULTS: Using molecular cytogenetics, we mapped the four breakpoints to 7p21.1-15.3 (chromosome position: 20,954,043-21,001,537, hg19), 7q31 (chromosome position: 114,528,369-114,556,605, hg19), 7q21.3 (chromosome position: 93,884,065-93,933,453, hg19) and 11p12 (chromosome position: 38,601,145-38,621,572, hg19). These regions contain only non-coding transcripts (ENSG00000232790 on 7p21.1 and TCONS_00013886, TCONS_00013887, TCONS_00014353, TCONS_00013888 on 7q21) indicating that no coding sequences are directly disrupted. The breakpoint on 7q31 mapped 200 kb downstream of FOXP2, a well-known language gene. No splice site or non-synonymous coding variants were found in the FOXP2 coding sequence. We were unable to detect any changes in the expression level of FOXP2 in fibroblast cells derived from the proband, although this may be the result of the low expression level of FOXP2 in these cells. CONCLUSIONS: We conclude that the phenotype observed in this patient either arises from a subtle change in FOXP2 regulation due to the disruption of a downstream element controlling its expression, or from the direct disruption of non-coding RNAs

    Quasi-Monte Carlo rules for numerical integration over the unit sphere S2\mathbb{S}^2

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    We study numerical integration on the unit sphere S2R3\mathbb{S}^2 \subset \mathbb{R}^3 using equal weight quadrature rules, where the weights are such that constant functions are integrated exactly. The quadrature points are constructed by lifting a (0,m,2)(0,m,2)-net given in the unit square [0,1]2[0,1]^2 to the sphere S2\mathbb{S}^2 by means of an area preserving map. A similar approach has previously been suggested by Cui and Freeden [SIAM J. Sci. Comput. 18 (1997), no. 2]. We prove three results. The first one is that the construction is (almost) optimal with respect to discrepancies based on spherical rectangles. Further we prove that the point set is asymptotically uniformly distributed on S2\mathbb{S}^2. And finally, we prove an upper bound on the spherical cap L2L_2-discrepancy of order N1/2(logN)1/2N^{-1/2} (\log N)^{1/2} (where NN denotes the number of points). This slightly improves upon the bound on the spherical cap L2L_2-discrepancy of the construction by Lubotzky, Phillips and Sarnak [Comm. Pure Appl. Math. 39 (1986), 149--186]. Numerical results suggest that the (0,m,2)(0,m,2)-nets lifted to the sphere S2\mathbb{S}^2 have spherical cap L2L_2-discrepancy converging with the optimal order of N3/4N^{-3/4}

    Molecular and Electrophysiological Characterization of GFP-Expressing CA1 Interneurons in GAD65-GFP Mice

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    The use of transgenic mice in which subtypes of neurons are labeled with a fluorescent protein has greatly facilitated modern neuroscience research. GAD65-GFP mice, which have GABAergic interneurons labeled with GFP, are widely used in many research laboratories, although the properties of the labeled cells have not been studied in detail. Here we investigate these cells in the hippocampal area CA1 and show that they constitute ∼20% of interneurons in this area. The majority of them expresses either reelin (70±2%) or vasoactive intestinal peptide (VIP; 15±2%), while expression of parvalbumin and somatostatin is virtually absent. This strongly suggests they originate from the caudal, and not the medial, ganglionic eminence. GFP-labeled interneurons can be subdivided according to the (partially overlapping) expression of neuropeptide Y (42±3%), cholecystokinin (25±3%), calbindin (20±2%) or calretinin (20±2%). Most of these subtypes (with the exception of calretinin-expressing interneurons) target the dendrites of CA1 pyramidal cells. GFP-labeled interneurons mostly show delayed onset of firing around threshold, and regular firing with moderate frequency adaptation at more depolarized potentials

    Common variation near ROBO2 is associated with expressive vocabulary in infancy

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    Twin studies suggest that expressive vocabulary at ~24 months is modestly heritable. However, the genes influencing this early linguistic phenotype are unknown. Here we conduct a genome-wide screen and follow-up study of expressive vocabulary in toddlers of European descent from up to four studies of the EArly Genetics and Lifecourse Epidemiology consortium, analysing an early (15–18 months, ‘one-word stage’, NTotal=8,889) and a later (24–30 months, ‘two-word stage’, NTotal=10,819) phase of language acquisition. For the early phase, one single-nucleotide polymorphism (rs7642482) at 3p12.3 near ​ROBO2, encoding a conserved axon-binding receptor, reaches the genome-wide significance level (P=1.3 × 10−8) in the combined sample. This association links language-related common genetic variation in the general population to a potential autism susceptibility locus and a linkage region for dyslexia, speech-sound disorder and reading. The contribution of common genetic influences is, although modest, supported by genome-wide complex trait analysis (meta-GCTA h215–18-months=0.13, meta-GCTA h224–30-months=0.14) and in concordance with additional twin analysis (5,733 pairs of European descent, h224-months=0.20)

    Jugoslavija u međunarodnoj trgovini ribom, ribljim proizvodima i prerađevinama

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    Sulfonamides are profoundly important in pharmaceutical design. C–N cross-coupling of sulfonamides is an effective method for fragment coupling and structure–activity relationship (SAR) mining. However, cross-coupling of the important <i>N</i>-arylsulfonamide pharmacophore has been notably unsuccessful. Here, we present a solution to this problem via oxidative Cu-catalysis (Chan–Lam cross-coupling). Mechanistic insight has allowed the discovery and refinement of an effective cationic Cu catalyst to facilitate the practical and scalable Chan–Lam <i>N</i>-arylation of primary and secondary <i>N</i>-arylsulfonamides at room temperature. We also demonstrate utility in the large scale synthesis of a key intermediate to a clinical hepatitis C virus treatment

    Point sets on the sphere S2\mathbb{S}^2 with small spherical cap discrepancy

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    In this paper we study the geometric discrepancy of explicit constructions of uniformly distributed points on the two-dimensional unit sphere. We show that the spherical cap discrepancy of random point sets, of spherical digital nets and of spherical Fibonacci lattices converges with order N1/2N^{-1/2}. Such point sets are therefore useful for numerical integration and other computational simulations. The proof uses an area-preserving Lambert map. A detailed analysis of the level curves and sets of the pre-images of spherical caps under this map is given
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