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https://www.readbyqxmd.com/read/29777400/ontogeny-of-anastomosed-laticifers-in-the-stem-apex-of-hancornia-speciosa-apocynaceae-a-topographic-approach
#1
Mayara Pereira Gonçalves, Maria Olívia Mercadante-Simões, Leonardo Monteiro Ribeiro
Latex is a complex plant secretion with both ecological and economic importance. There is little information currently available on the cytological aspects of the ontogenesis of anastomosed laticifers, the ducts originating through the lysis of adjacent cell walls. Hancornia speciosa is a tree typical of the Cerrado (neotropical savanna) biome. Its latex has medicinal value and is also used to produce rubber. The ontogenesis of its laticifers and the process of latex synthesis are described here. Structural, cytochemical, and ultrastructural analyses of the stem apex and phytochemical analyses of the latex were performed...
May 18, 2018: Protoplasma
https://www.readbyqxmd.com/read/29768481/complexity-in-african-savannas-direct-indirect-and-cascading-effects-of-animal-densities-rainfall-and-vegetation-availability
#2
Tim Leeuwis, Mike Peel, Willem F de Boer
Savanna ecosystems are popular subjects for interaction studies. Multiple studies have been done on the impact of elephants on vegetation, the impact of grass and browse availability on animal densities or on competition between herbivore species. Previous studies showed that elephant densities are frequently negatively correlated with densities of tall trees, and that browse and grass availability are correlated with browser and grazer density respectively. Additionally, a competition effect between browse and grass availability has been reported...
2018: PloS One
https://www.readbyqxmd.com/read/29768190/a-bayesian-model-comparison-approach-to-test-the-specificity-of-visual-integration-impairment-in-schizophrenia-or-psychosis
#3
Tyler B Grove, Beier Yao, Savanna A Mueller, Merranda McLaughlin, Vicki L Ellingrod, Melvin G McInnis, Stephan F Taylor, Patricia J Deldin, Ivy F Tso
Impaired visual integration is well documented in schizophrenia and related to functional outcomes. However, it is unclear if this deficit is specific to schizophrenia, or characteristic of psychosis more broadly. To address this question, this study used a Bayesian model comparison approach to examine the evidence of three grouping models of visual integration performance in 116 individuals with schizophrenia (SZ), schizoaffective disorder (SA), bipolar disorder (BD) with or without a history of prominent psychosis (BDP+ and BDP-, respectively), or no psychiatric diagnosis (healthy controls; HC)...
May 7, 2018: Psychiatry Research
https://www.readbyqxmd.com/read/29766371/landsat-phenological-metrics-and-their-relation-to-aboveground-carbon-in-the-brazilian-savanna
#4
M Schwieder, P J Leitão, J R R Pinto, A M C Teixeira, F Pedroni, M Sanchez, M M Bustamante, P Hostert
BACKGROUND: The quantification and spatially explicit mapping of carbon stocks in terrestrial ecosystems is important to better understand the global carbon cycle and to monitor and report change processes, especially in the context of international policy mechanisms such as REDD+ or the implementation of Nationally Determined Contributions (NDCs) and the UN Sustainable Development Goals (SDGs). Especially in heterogeneous ecosystems, such as Savannas, accurate carbon quantifications are still lacking, where highly variable vegetation densities occur and a strong seasonality hinders consistent data acquisition...
May 15, 2018: Carbon Balance and Management
https://www.readbyqxmd.com/read/29754291/defence-strategies-in-african-savanna-trees
#5
Benjamin J Wigley, Hervé Fritz, Corli Coetsee
Southern African savannas are commonly polarised into two broad types based on plant functional types and defences; infertile savannas dominated by broad-leaved trees typically defended by nitrogen-free secondary compounds and fertile savannas dominated by fine-leaved trees defended by structural defences. In this study, we use trait and other data from 15 wooded savanna sites in Southern Africa and ask if broad-leaved and fine-leaved species dominate on nutrient-poor and nutrient-rich soils, respectively. We then test if there is there any evidence for trade-offs in chemical (i...
May 12, 2018: Oecologia
https://www.readbyqxmd.com/read/29752729/conservation-lessons-from-large-mammal-manipulations-in-east-african-savannas-the-klee-uhuru-and-glade-experiments
#6
REVIEW
Jacob R Goheen, David J Augustine, Kari E Veblen, Duncan M Kimuyu, Todd M Palmer, Lauren M Porensky, Robert M Pringle, Jayashree Ratnam, Corinna Riginos, Mahesh Sankaran, Adam T Ford, Abdikadir A Hassan, Rhiannon Jakopak, Tyler R Kartzinel, Samson Kurukura, Allison M Louthan, Wilfred O Odadi, Tobias O Otieno, Alois M Wambua, Hillary S Young, Truman P Young
African savannas support an iconic fauna, but they are undergoing large-scale population declines and extinctions of large (>5 kg) mammals. Long-term, controlled, replicated experiments that explore the consequences of this defaunation (and its replacement with livestock) are rare. The Mpala Research Centre in Laikipia County, Kenya, hosts three such experiments, spanning two adjacent ecosystems and environmental gradients within them: the Kenya Long-Term Exclosure Experiment (KLEE; since 1995), the Glade Legacies and Defaunation Experiment (GLADE; since 1999), and the Ungulate Herbivory Under Rainfall Uncertainty experiment (UHURU; since 2008)...
May 11, 2018: Annals of the New York Academy of Sciences
https://www.readbyqxmd.com/read/29752682/new-perspectives-in-fire-management-in-south-american-savannas-the-importance-of-intercultural-governance
#7
Jayalaxshmi Mistry, Isabel Belloni Schmidt, Ludivine Eloy, Bibiana Bilbao
Wildfires continue to cause damage to property, livelihoods and environments around the world. Acknowledging that dealing with wildfires has to go beyond fire-fighting, governments in countries with fire-prone ecosystems have begun to recognize the multiple perspectives of landscape burning and the need to engage with local communities and their practices. In this perspective, we outline the experiences of Brazil and Venezuela, two countries where fire management has been highly contested, but where there have been recent advances in fire management approaches...
May 11, 2018: Ambio
https://www.readbyqxmd.com/read/29738723/tropical-savannas-and-dry-forests
#8
R Toby Pennington, Caroline E R Lehmann, Lucy M Rowland
In the tropics, research, conservation and public attention focus on rain forests, but this neglects that half of the global tropics have a seasonally dry climate. These regions are home to dry forests and savannas (Figures 1 and 2), and are the focus of this Primer. The attention given to rain forests is understandable. Their high species diversity, sheer stature and luxuriance thrill biologists today as much as they did the first explorers in the Age of Discovery. Although dry forest and savanna may make less of a first impression, they support a fascinating diversity of plant strategies to cope with stress and disturbance including fire, drought and herbivory...
May 7, 2018: Current Biology: CB
https://www.readbyqxmd.com/read/29727926/estimating-terrestrial-gross-primary-productivity-in-water-limited-ecosystems-across-africa-using-the-southampton-carbon-flux-scarf-model
#9
P Chiwara, B O Ogutu, J Dash, E J Milton, J Ardö, M Saunders, G Nicolini
The amount of carbon uptake by vegetation is an important component to understand the functioning of ecosystem processes and their response/feedback to climate. Recently, a new diagnostic model called the Southampton Carbon Flux (SCARF) Model driven by remote sensing data was developed to predict terrestrial gross primary productivity (GPP) and successfully applied in temperate regions. The model is based on the concept of quantum yield of plants and improves on the previous diagnostic models by (i) using the fraction of photosynthetic active radiation absorbed by the photosynthetic pigment (FAPARps ) and (ii) using direct quantum yield by classifying the vegetation into C3 or C4 classes...
July 15, 2018: Science of the Total Environment
https://www.readbyqxmd.com/read/29724253/local-ecological-knowledge-concerning-the-invasion-of-amerindian-lands-in-the-northern-brazilian-amazon-by-acacia-mangium-willd
#10
REVIEW
Arlene Oliveira Souza, Maria do Perpétuo Socorro Rodrigues Chaves, Reinaldo Imbrozio Barbosa, Charles Roland Clement
INTRODUCTION: Invasive plants can impact biodiversity as well as the lives of native human populations. Natural ecosystems represent sources of natural resources essential for the subsistence and socio-cultural continuity of these social groups. Approximately 30,000 ha of Acacia mangium were planted for commercial purposes in savanna areas surrounding indigenous lands in Roraima State, Brazil, at the end of the 1990s. We examined the local ecological knowledge of indigenous Wapichana and Macuxi Amerindians, members of the Arawak and Carib linguistic families, respectively, concerning A...
May 3, 2018: Journal of Ethnobiology and Ethnomedicine
https://www.readbyqxmd.com/read/29717260/a-modified-gene-trap-approach-for-improved-high-throughput-cancer-drug-discovery
#11
Shelli M Morris, Andrew J Mhyre, Savanna S Carmack, Carrie H Myers, Connor Burns, Wenjuan Ye, Marc Ferrer, James M Olson, Richard A Klinghoffer
While advances in laboratory automation has dramatically increased throughout of compound screening efforts, development of robust cell-based assays in relevant disease models remain resource-intensive and time-consuming, presenting a bottleneck to drug discovery campaigns. To address this issue, we present a modified gene trap approach to efficiently generate pathway-specific reporters that result in a robust "on" signal when the pathway of interest is inhibited. In this proof-of-concept study, we used vemurafenib and trametinib to identify traps that specifically detect inhibition of the mitogen-activated protein kinase (MAPK) pathway in a model of BRAFV600E driven human malignant melanoma...
May 2, 2018: Oncogene
https://www.readbyqxmd.com/read/29701243/cerrado-small-mammals-a-dataset-of-abundance-and-distribution-of-marsupials-lagomorphs-and-rodents-in-a-neotropical-savanna
#12
André F Mendonça, Alexandre R Percequillo, Nicholas F de Camargo, Juliana F Ribeiro, Alexandre R T Palma, Leonardo C Oliveira, Edeltrudes M V C Câmara, Emerson M Vieira
Patterns in distribution and local abundance of species within a biome are central concerns in ecology and allow the understanding of the effects of habitat loss on rates of species extinction; provide support for the creation and management of reserves; and contribute to the identification and quantification of the processes that allow niche partitioning by species. However, despite the importance in the conservation and management of the ecosystems, most systematized information on the abundance and distribution of small mammals is restricted to the northern hemisphere or forest ecosystems...
April 27, 2018: Ecology
https://www.readbyqxmd.com/read/29700374/exotic-grass-invasion-alters-microsite-conditions-limiting-woody-recruitment-potential-in-an-australian-savanna
#13
Samantha A Setterfield, Peter J Clifton, Lindsay B Hutley, Natalie A Rossiter-Rachor, Michael M Douglas
Andropogon gayanus Kunth. is a large African tussock grass invading Australia's tropical savannas. Invasion results in more intense fires which increases the mortality rate of adult woody plants. Invasion may also affect community structure by altering the recruitment potential of woody plants. We investigated the effects of A. gayanus invasion on ground-level microclimate, and the carbon assimilation potential and recruitment potential of two Eucalyptus species. We compared microclimatic variables from the early wet-season and into the mid-dry season to coincide with the period of growth of A...
April 26, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29694698/using-imaging-spectroscopy-to-detect-variation-in-terrestrial-ecosystem-productivity-across-a-water-stressed-landscape
#14
Sean DuBois, Ankur R Desai, Aditya Singh, Shawn P Serbin, Michael L Goulden, Dennis D Baldocchi, Siyan Ma, Walter C Oechel, Sonia Wharton, Eric L Kruger, Philip A Townsend
A central challenge to understanding how climate anomalies, such as drought and heatwaves, impact the terrestrial carbon cycle, is quantification and scaling of spatial and temporal variation in ecosystem gross primary productivity (GPP). Existing empirical and model-based satellite broadband spectra-based products have been shown to miss critical variation in GPP. Here, we evaluate the potential of high spectral resolution (10 nm) shortwave (400-2500 nm) imagery to better detect spatial and temporal variations in GPP across a range of ecosystems, including forests, grassland-savannas, wetlands, and shrublands in a water-stressed region...
April 25, 2018: Ecological Applications: a Publication of the Ecological Society of America
https://www.readbyqxmd.com/read/29693438/overdispersed-spatial-patterning-of-dominant-bunchgrasses-in-southeastern-pine-savannas
#15
Katherine A Hovanes, Kyle E Harms, Paul R Gagnon, Jonathan A Myers, Bret D Elderd
Spatial patterning is a key natural history attribute of sessile organisms that frequently emerges from and dictates potential for interactions among organisms. We tested whether bunchgrasses, the dominant plant functional group in longleaf pine savanna groundcover communities, are nonrandomly patterned by characterizing the spatial dispersion of three bunchgrass species across six sites in Louisiana and Florida. We mapped bunchgrass tussocks of >5.0 cm basal diameter in three [Formula: see text] plots at each site...
May 2018: American Naturalist
https://www.readbyqxmd.com/read/29689993/a-new-blind-snake-of-the-genus-letheobia-serpentes-typhlopidae-from-rwanda-with-redescriptions-of-l-gracilis-sternfeld-1910-and-l-graueri-sternfeld-1912-and-the-introduction-of-a-non-invasive-preparation-procedure-for-scanning-electron-microscopy-in-zoology
#16
J Maximilian Dehling, Harald H Hinkel, Hans-jÜrgen Ensikat, Kenny Babilon, Eberhard Fischer
A new species of blind snake in the genus Letheobia is described from Akagera National Park in eastern Rwanda. The new species is most similar to species of the L. gracilis complex, particularly L. gracilis and L. graueri. It differs from all other species of the genus by a unique combination of morphological characters, including the highest number of middorsal scale rows (834) and the most extreme elongation (total-length/midbody-width ratio 131) of all species in the genus and of any species of snake in the world; 22-22-22 longitudinal scale rows; snout in dorsal profile rounded, in lateral profile bluntly rounded with an angular horizontal edge ventrally; rostral broad, posteriorly rounded; eyes invisible; supralabial imbrication pattern T-0; tail short (1...
February 11, 2018: Zootaxa
https://www.readbyqxmd.com/read/29686843/the-influence-of-biogeographic-history-on-the-functional-and-phylogenetic-diversity-of-passerine-birds-in-savannas-and-forests-of-the-brazilian-amazon
#17
Sara Miranda Almeida, Leandro Juen, Fernando Landa Sobral, Marcos Pérsio Dantas Santos
Passeriformes is the largest and most diverse avian order in the world and comprises the Passeri and Tyranni suborders. These suborders constitute a monophyletic group, but differ in their ecology and history of occupation of South America. We investigated the influence of biogeographic history on functional and phylogenetic diversities of Passeri and Tyranni in forest and savanna habitats in the Brazilian Amazon. We compiled species composition data for 34 Passeriformes assemblages, 12 in savannas and 22 in forests...
April 2018: Ecology and Evolution
https://www.readbyqxmd.com/read/29685749/the-costs-of-living-at-the-edge-seasonal-stress-in-wild-savanna-dwelling-chimpanzees
#18
Erin G Wessling, Hjalmar S Kühl, Roger Mundry, Tobias Deschner, Jill D Pruetz
Adaptations associated with shifting from a predominately forested habitat to a more open environment are considered a crucial step in hominin evolution. Understanding how chimpanzees, one of our closest-living relatives, are exposed to the selection pressures associated with living in a relatively sparse, hot, and dry environment can inform us about the relative importance of potential environmental stressors involved in adaptations to drier environments. We investigated the extent to which chimpanzees living in an extreme savanna habitat experience seasonal variability in either energy balance or thermoregulation (dehydration and heat exposure), as well as whether these potential environmental constraints are taxing to chimpanzee individuals...
April 20, 2018: Journal of Human Evolution
https://www.readbyqxmd.com/read/29685298/the-suitability-of-visual-taphonomic-methods-for-digital-photographs-an-experimental-approach-with-pig-carcasses-in-a-tropical-climate
#19
Agathe Ribéreau-Gayon, Carolyn Rando, Ruth M Morgan, David O Carter
In the context of increased scrutiny of the methods in forensic sciences, it is essential to ensure that the approaches used in forensic taphonomy to measure decomposition and estimate the postmortem interval are underpinned by robust evidence-based data. Digital photographs are an important source of documentation in forensic taphonomic investigations but the suitability of the current approaches for photographs, rather than real-time remains, is poorly studied which can undermine accurate forensic conclusions...
May 2018: Science & Justice: Journal of the Forensic Science Society
https://www.readbyqxmd.com/read/29674787/distinct-isotopic-signatures-reveal-effect-of-ecoregion-on-small-mammals-of-ghana
#20
Nyeema C Harris, Reuben A Garshong, Morgan Gray
Species reside in dynamic environments, simultaneously experiencing variations in climatic conditions, habitat availability and quality, interspecific interactions, and anthropogenic pressures. We investigated variation in foraging ecology of the small mammal community between land-use classifications (i.e., protected national parks and unprotected lands abutting them) in Mole National Park (MNP) and Digya National Park (DNP), representing distinct ecoregions of Ghana. In 5,064 trap nights, we sampled 153 individuals of 23 species within the 2 national parks and adjacent lands outside protected boundaries to describe variation in community composition...
February 1, 2018: Journal of Mammalogy
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