1,794 research outputs found
Regression towards the mode
We propose a semi-parametric mode regression estimator for the case in which the variate of interest is continuous and observable over its entire un- bounded support. The estimator is semi-parametric in that the conditional mode is specified as a parametric function, but only mild assumptions are made about the nature of the conditional density of interest. We show that the proposed estimator is consistent and has a tractable asymptotic distribution. Simulation results and an empirical illustration are provided to highlight the practicality and usefulness of the estimator.
Environmental heterogeneity caused by anthropogenic disturbance drives forest structure and dynamics in Brazilian Atlantic Forest
We evaluated how tree community floristic composition, forest structure and dynamics varied over a period of 13 years across a topographic gradient of ravines created by anthropic disturbance in Brazilian Atlantic Forest. The study area is located within a fragment of Atlantic Forest (21° 09' S, 44° 54' W), in Minas Gerais state, Brazil. This work was based on data of tree diameter at 1.3 m from the soil, collected in four inventories. Each individual was recorded as being in one of three stratified topographic classes: hilltop, slope and bottom. We used direct gradient analysis to evaluate floristic compositional changes, phytosociological analysis to evaluate structural variations, and assessed demographic and biomass changes over time through analysis of rates of forest dynamics. The results did not reflect modifications in the patterns of floristic composition and species diversity along the topographic gradient, while differences in forest structural attributes and dynamics may be detected at these smaller spatial scales. Thus, the same species group may employ different strategies against different restrictive environmental factors. Finally, we suggest that floristic composition and species diversity may be less sensitive parameters for post-disturbance responses than forest dynamics and structure
Cissampelos sympodialis (Menispermaceae): A Novel Phytotherapic Weapon Against Allergic Diseases?
Inventário De Moluscos Do Estuário Do Rio Paraíba No Nordeste Do Brasil
Coastal ecosystems of northeastern Brazil have important biodiversity with regard to marine mollusks, which are insufficiently studied. Here we provide an inventory of mollusks from two sites in the estuary of the Paraíba River. Mollusks were collected in 2014 and 2016 on the coast and sandbanks located on the properties of Treze de Maio and Costinha de Santo Antônio. The malacofaunal survey identified 12 families, 20 genera and 21 species of bivalves, 17 families, 19 genera and 20 species of gastropods and one species of cephalopod. Bivalves of the family Veneridae Rafinesque, 1815 were the most representative, with a total of five species. Gastropods of the family Littorinidae Children, 1834 had the greatest species richness. The most abundant species were: Neritina virginea (Linnaeus, 1758), Brachidontes exustus (Linnaeus, 1758), Crassostrea brasiliana (Lamarck, 1819), Cerithium atratum (Born, 1778), Anomalocardia brasiliana (Gmelin, 1791), Parvanachis obesa (C. B. Adams, 1845), Phrontis polygonata (Lamarck, 1822), Littoraria angulifera (Lamarck, 1822), L. flava (King, 1832), Tagelus plebeius (Lightfoot, 1786), Echinolittorina lineolata (d’Orbigny, 1840) and Iphigenia brasiliensis (Lamarck, 1818). The results show that the study area has considerable species richness of Mollusca, requiring environmental monitoring in the region mainly due to the economic importance of some species to the local population. © 2017, Universidade Estadual de Campinas UNICAMP. All rights reserved.17
New bounds for Tsallis parameter in a noncommutative phase-space entropic gravity and nonextensive Friedmann equations
In this paper, we have analyzed the nonextensive Tsallis statistical
mechanics in the light of Verlinde's formalism. We have obtained, with the aid
of a noncommutative phase-space entropic gravity, a new bound for Tsallis
nonextensive (NE) parameter (TNP) that is clearly different from the ones
present in the current literature. We derived the Friedmann equations in a NE
scenario. We also obtained here a relation between the gravitational constant
and the TNP.Comment: 15 pages. Final version to appear in Physica
Different proportion of root cutting and shoot pruning influence the growth of citronella plants
Environment concern, sustainable products demand, and natural components
conscious are currently global movement factors. Related to the global movement factors,
citronella grass (Cymbopogon nardus L.) is being widely used in folk medicine, and has insect
repellent activity, fungal and bactericidal action. Its essential oil has high content of citronellal,
citronellol, geraniol. The essential oil is mostly extracted from leaves which turns this plant with
high commercial demand. However, to obtain the best therapeutic quality and productivity of
medicinal plants, which culminates in greater quantity and quality of the active compounds, the
proper management of the crop is fundamental, as several factors can interfere during its growth
and development. Thus, we analyzed the growth of citronella plants submitted to different levels
of shoot and root cuts. Five different proportions of root pruning (0, 25, 50, 75, 100%), after 145
days of seedling planting and four cuttings in the shoots: blunt; a cut at 145 DAP (days after
planting) along with the root cut; a cut at 228 DAP; and cuts at 145 and 228 DAP (two cuts). Four
harvesting for dry matter accumulation and photoassimilate partition data were performed. The
treatment with 100% root cut, but without leaf cut, increased the total dry mass accumulation of
the plant in relation to the other treatments, for the last analysis period, demonstrating a recovery.
Thus, the application of two leaf cuts or no leaf cutting within the 100% root cut treatment for
leaf dry mass accumulation is more effective when compared to the blunt root treatment
Novel ageing-biomarker discovery using data-intensive technologies
Ageing is accompanied by many visible characteristics. Other biological and physiological markers are also well-described e.g. loss of circulating sex hormones and increased inflammatory cytokines. Biomarkers for healthy ageing studies are presently predicated on existing knowledge of ageing traits. The increasing availability of data-intensive methods enables deep-analysis of biological samples for novel biomarkers. We have adopted two discrete approaches in MARK-AGE Work Package 7 for biomarker discovery; (1) microarray analyses and/or proteomics in cell systems e.g. endothelial progenitor cells or T cell ageing including a stress model; and (2) investigation of cellular material and plasma directly from tightly-defined proband subsets of different ages using proteomic, transcriptomic and miR array. The first approach provided longitudinal insight into endothelial progenitor and T cell ageing.This review describes the strategy and use of hypothesis-free, data-intensive approaches to explore cellular proteins, miR, mRNA and plasma proteins as healthy ageing biomarkers, using ageing models and directly within samples from adults of different ages. It considers the challenges associated with integrating multiple models and pilot studies as rational biomarkers for a large cohort study. From this approach, a number of high-throughput methods were developed to evaluate novel, putative biomarkers of ageing in the MARK-AGE cohort
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