32 research outputs found
An estimate of the number of tropical tree species
The high species richness of tropical forests has long been recognized, yet there remains substantial uncertainty regarding the actual number of tropical tree species. Using a pantropical tree inventory database from closed canopy forests, consisting of 657,630 trees belonging to 11,371 species, we use a fitted value of Fisher’s alpha and an approximate pantropical stem total to estimate the minimum number of tropical forest tree species to fall between ∼40,000 and ∼53,000, i.e. at the high end of previous estimates. Contrary to common assumption, the Indo-Pacific region was found to be as species-rich as the Neotropics, with both regions having a minimum of ∼19,000–25,000 tree species. Continental Africa is relatively depauperate with a minimum of ∼4,500–6,000 tree species. Very few species are shared among the African, American, and the Indo-Pacific regions. We provide a methodological framework for estimating species richness in trees that may help refine species richness estimates of tree-dependent taxa
Consistent patterns of common species across tropical tree communities
Trees structure the Earth’s most biodiverse ecosystem, tropical forests. The vast number of tree species presents a formidable challenge to understanding these forests, including their response to environmental change, as very little is known about most tropical tree species. A focus on the common species may circumvent this challenge. Here we investigate abundance patterns of common tree species using inventory data on 1,003,805 trees with trunk diameters of at least 10 cm across 1,568 locations1,2,3,4,5,6 in closed-canopy, structurally intact old-growth tropical forests in Africa, Amazonia and Southeast Asia. We estimate that 2.2%, 2.2% and 2.3% of species comprise 50% of the tropical trees in these regions, respectively. Extrapolating across all closed-canopy tropical forests, we estimate that just 1,053 species comprise half of Earth’s 800 billion tropical trees with trunk diameters of at least 10 cm. Despite differing biogeographic, climatic and anthropogenic histories7, we find notably consistent patterns of common species and species abundance distributions across the continents. This suggests that fundamental mechanisms of tree community assembly may apply to all tropical forests. Resampling analyses show that the most common species are likely to belong to a manageable list of known species, enabling targeted efforts to understand their ecology. Although they do not detract from the importance of rare species, our results open new opportunities to understand the world’s most diverse forests, including modelling their response to environmental change, by focusing on the common species that constitute the majority of their trees.Publisher PDFPeer reviewe
Increased serum miR-193a-5p during non-alcoholic fatty liver disease progression: diagnostic and mechanistic relevance
Background & Aims: Serum microRNAs (miRNAs) levels are known to change in non-alcoholic fatty liver disease (NAFLD) and may serve as useful biomarkers. This study aimed to profile miRNAs comprehensively at all NAFLD stages.Methods: We profiled 2,083 serum miRNAs in a discovery cohort (183 NAFLD cases representing the complete NAFLD spectrum and 10 population controls). MiRNA libraries generated by HTG EdgeSeq were sequenced by Illumina NextSeq. Selected serum miRNAs were profiled in 372 additional NAFLD cases and 15 population controls by quantitative reverse transcriptase-polymerase chain reaction.Results: Levels of 275 miRNAs differed between cases and population controls. Fewer differences were seen within individual NAFLD stages but miR-193a-5p consistently the showed increased levels in all comparisons. Relative to NAFL/NASH with mild fibrosis (stage 0/1), three miRNAs (miR-193a-5p, miR-378d and miR378d) were increased in cases with NASH and clinically significant fibrosis (stage 2-4), seven (miR193a-5p, miR-378d, miR-378e, miR-320b, c, d & e) increased in cases with NAFLD Activity Score (NAS) 5-8 compared with lower NAS, and three (miR-193a-5p, miR-378d, miR-378e) increased but one (miR-19b-3p) decreased in steatosis, activity, and fibrosis "activity" (SAF-A) score 2-4 compared with lower SAF-A. The significant findings for miR-193a-5p were replicated in the additional NAFLD cohort. Studies in Hep G2 cells showed that following palmitic acid treatment, miR-193a-5p expression decreased significantly. Gene targets for miR-193a-5p were investigated in liver RNAseq data for a case subgroup (n=80); liver GPX8 levels correlated positively with serum miR-193a-5p. Conclusions: Serum miR-193a-5p levels correlate strongly with NAFLD activity grade and fibrosis stage. MiR-193a-5p may have a role in the hepatic response to oxidative stress and is a potential clinically tractable circulating biomarker for progressive NAFLD
Proposta d’un nou mètode per a la millora del rendiment en pilota valenciana: SIT
Durant els últims anys, s’ha incrementat l’entrenament amb treball de resistència usant mètodes intervàlics d’esprints de màxima intensitat (SIT). Diverses recer- ques han demostrat que amb SIT s’obtenen adaptacions similars o millors que amb l’entrenament continu, però amb un volum de treball molt reduït.
Aquest article té per objecte l’aplicació del mètode SIT per part dels entrenadors de pilota, perquè la necessitat de menys temps d’entrenament i dels pocs recursos materials necessaris permeten un entrenament més òptim en la millora de la resis- tència de l’esportista, de manera que s’arriba a mantindre la intensitat durant més temps i es poden repetir més activitats intenses durant el partit.
Aquest estudi no s’ha dut a terme en pilotaris, però proposa un mètode amb molta transferència al nostre esport. Concretament, van ser 16 subjectes corredors de muntanya entrenats (21,2 ± 2,6 anys).Ciencias de la Actividad Física y del Deport
Neural correlates of rehabilitation program with robot-assisted intensive therapy in one case of Holmes tremor
International audienceHolmes tremor (HT) is a rare movement disorder characterized by low-frequency tremor, inferior to 5 Hz, at rest and during postural and intentional conditions (1). It severely alters the functional abilities. The pathophysiology of tremor is unknown. However, dysfunctions of cortico-ponto-cerebello-thalamo-cortical loops were hypothesized by Bucy in 1944 and confirmed since notably in HT (2,3), involving contralateral sensorimotor and prefrontal cortices and the ipsilateral cerebellum. Treatments of HT include levodopa, dopamine agonists, anticholinergics, propranolol, primidone, levetiracetam, more recently botulinum toxin and deep brain stimulation, with variable and unpredictable responses (4). Hence we built a personalized rehabilitation program with intensive robotic rehabilitation, as proposed after stroke (5), associated to classical human-guided rehabilitation, in one case of HT. The lesions were scrutinized using structural magnetic resonance imaging (MRI). Both clinical effects and functional MRI (fMRI) activations were studied before and after rehabilitation, willing to explore underlying neural correlates
Re: Re: ``Adult appendicitis: Clinical practice guidelines from the French Society of Digestive Surgery (SFCD) and the Society of Abdominal and Digestive Imaging (SIAD)
International audienc
The effects of exercise intensity or drafting during swimming on subsequent cycling performance in triathletes
David J. Bentley, Sebastien Libicz, Aurelie Jougla, Olivier Coste, Jerome Manettac, Karim Chamari and Gregoire P. Millethttp://www.elsevier.com/wps/find/journaldescription.cws_home/707423/description#descriptio
Characterization of a novel strain of Aspergillus aculeatinus: From rhamnogalacturonan type I pectin degradation to improvement of fruit juice filtration
International audienceAspergillus spp. are well-known producers of pectinases commonly used in the industry. Aspergillus aculeatinus is a recently identified species but poorly characterized. This study aimed at giving a comprehensive characterization of the enzymatic potential of the O822 strain to produce Rhamnogalacturonan type I (RGI)-degrading enzymes. Proteomic analysis identified cell wall degrading enzymes (cellulases, hemicellulases, and pectinases) that accounted for 92 % of total secreted proteins. Twelve out of fifty proteins were identified as RGI-degrading enzymes. NMR and enzymatic assays revealed high levels of arabinofuranosidase, arabinanase, galactanase, rhamnogalacturonan hydrolases and rhamnogalacturonan acetylesterase activities in aqueous extracts. Viscosity assays carried out with RGI-rich camelina mucilage confirmed the efficiency of enzymes secreted by O822 to hydrolyze RGI, by decreasing viscosity by 70 %. Apple juice trials carried out at laboratory and pilot scale showed an increase in filtration flow rate and yield, paving the way for an industrial use of enzymes derived from A. aculeatinus
Real life experience of mycophenolate mofetil monotherapy in liver transplant patients
International audienceBACKGROUND: Mycophenolate mofetil (MMF) monotherapy following liver transplantation (LT) remains controversial due to a risk of acute rejection. The aim of this study was to report the largest multicenter experience of the use a MMF monotherapy guided by therapeutic drug monitoring using pharmacoslope modeling and Bayesian estimations of the MPA inter-dose AUC (BEMPAMETHODS: MMF daily doses were adjusted to reach the BEMPARESULTS: From 2000-2014, in 2 transplantation centers, 94 liver transplant recipients received MMF monotherapy 6.5±4 years after LT. The mean BEMPACONCLUSIONS: MMF monotherapy regimen appears usually safe and beneficial, with low risk of acute rejection and eGFR improvement. Therapeutic drug monitoring strategy seemed useful by identifying 14% of patients with low MMF exposure