Disentangling the influence of local and landscape factors on alpha and beta diversities: opposite response of plants and ground-dwelling arthropods in wet meadows

International audienceA large number of studies have tried to understand the determinants of local species richness, i.e. α-diversity. Studies dealing with β-diversity are considerably less numerous but their number has increased in the recent years. In this study, we assessed the relative importance of local and landscape (i.e. composition and connectivity) variables in explaining α- and β-diversities (species turnover and nestedness) of three highly diverse groups, differing in mobility and dispersal: plants, spiders, and carabids. Sampling took place in 2013, using suction samplers for arthropods and phytosociological relevés for vegetation, in 77 hay meadows distributed along 200 km of the Loire Valley (France). We found plant α-diversity to be driven by local factors, whereas spider and carabid α-diversities were mostly determined by landscape factors (by composition and connectivity, respectively). Nestedness was negligible for the three groups. Plant β-diversity was also mainly influenced by local factors, whereas spider β-diversity was driven by landscape factors (composition and connectivity, equally). Surprisingly, carabid β-diversity was mainly influenced by local factors and landscape connectivity. Despite these differences, plant, spider, and carabid β-diversities were not different, suggesting comparable dispersal abilities and/or a low connectivity at large scale, which is in accordance with the high species turnover observed here. Managing biodiversity in meadows consequently necessitates acting at local and landscape scales, the first targeting plants and the second arthropod

Vegetation maps based on remote sensing are informative predictors of habitat selection of grassland birds across a wetness gradient

Vegetation is a major environmental factor influencing habitat selection in bird species. High resolution mapping of vegetation cover is essential to model the distribution of populations and improve the management of breeding habitats. However, the task is challenging for grassland birds because microhabitat variations relevant at the territory scale cannot be measured continuously over large areas to delineate areas of higher suitability. Remote sensing may help to circumvent this problem. We addressed this issue by using two methods. We (i) mapped the continuous Ellenberg index of moisture and (ii) identified 5 vegetation classes distributed accross the wetness gradient. These two methods produced consistent output maps, but they also provided more information about vegetation structure, and possibly trophic resources. In spite of the apprent uniformity of meadows, our data show that birds do not settle randomly along the moisture and vegetation gradients. Overall birds tend to avoid the driest vegetation classes, i.e. the highest grounds. Thus, vegetation maps based on remote sensing could be valuable tools to study habitat selection and niche partition in grassland bird communities. It is also a valuable tool for conservation and habitat management

Determinants of image quality of rotational angiography for on-line assessment of frame geometry after transcatheter aortic valve implantation

To study the determinants of image quality of rotational angiography using dedicated research prototype software for motion compensation without rapid ventricular pacing after the implantation of four commercially available catheter-based valves. Prospective observational study including 179 consecutive patients who underwent transcatheter aortic valve implantation (TAVI) with either the Medtronic CoreValve (MCS), Edward-SAPIEN Valve (ESV), Boston Sadra Lotus (BSL) or Saint-Jude Portico Valve (SJP) in whom rotational angiography (R-angio) with motion compensation 3D image reconstruction was performed. Image quality was evaluated from grade 1 (excellent image quality) to grade 5 (strongly degraded). Distinction was made between good (grades 1, 2) and poor image quality (grades 3–5). Clinical (gender, body mass index, Agatston score, heart rate and rhythm, artifacts), procedural (valve type) and technical variables (isocentricity) were related with the image quality assessment. Image quality was good in 128 (72 %) and poor in 51 (28 %) patients. By univariable analysis only valve type (BSL) and the presence of an artefact negatively affected image quality. By multivariate analysis (in which BMI was forced into the model) BSL valve (Odds 3.5, 95 % CI [1.3–9.6], p = 0.02), presence of an artifact (Odds 2.5, 95 % CI [1.2–5.4], p = 0.02) and BMI (Odds 1.1, 95 % CI [1.0–1.2], p = 0.04) were independent predictors of poor image quality. Rotational angiography with motion compensation 3D image reconstruction using a dedicated research prototype software offers good image quality for the evaluation of frame geometry after TAVI in the majority of patients. Valve type, presence of artifacts and higher BMI negatively affect image quality

Clinical consequences of consecutive self-expanding transcatheter heart valve iterations

OBJECTIVE: To compare early clinical outcomes after transcatheter aortic valve implantation (TAVI) with three consecutive generations of self-expanding valves (SEVs). METHODS: Clinical endpoints of consecutive patients who underwent TAVI with CoreValve, Evolut R or Evolut PRO were included in a prospective database. RESULTS: TAVI was performed with CoreValve (n = 116), Evolut R (n = 160) or Evolut PRO (n = 92). Evolut R and Evolut PRO showed a tendency towards lower permanent pacemaker implantation (PPI) rates compared to CoreValve (CoreValve 27% vs Evolut R 16% vs Evolut PRO 18%, p = 0.091). By multivariable regression analysis CoreValve had a significantly higher risk for PPI (odds ratio (OR) 2.79, 95% confidence interval (CI) 1.31–5.94, p = 0.008) compared to Evolut R, while Evolut R and PRO were similar. Severe paravalvular leakage (PVL) occurred only with CoreValve, but no significant difference was observed in moderate PVL (10% vs 8% vs 6%, p = 0.49). CoreValve had a tendency towards a higher risk for more-than-mild PVL as compared with the Evolut platform (R + PRO) (OR 2.46, 95% CI 0.98–6.16, p = 0.055). No significant differences in all-cause mortality (7% vs 4% vs 1%, p = 0.10), stroke (6% vs 3% vs 2%, p = 0.21) or major vascular complications (10% vs 12% vs 4%, p = 0.14) were observed. CONCLUSIONS: TAVI with self-expanding valves was safe, and device iterations may result in a lower need for PPI. More-than-mild PVL seemed to occur less often with repositionable technology. SUPPLEMENTARY INFORMATION: The online version of this article (10.1007/s12471-021-01568-5) contains supplementary material, which is available to authorized users

Assimilation of phytate-phosphorus by the extracellular phytase activity of tobacco (Nicotiana tabacum) is affected by the availability of soluble phytate

Phytate, the major organic phosphorus in soil, is not readily available to plants as a source of phosphorus (P). It is either complexed with cations or adsorbed to various soil components. The present study was carried out to investigate the extracellular phytase activities of tobacco (Nicotiana tabacum variety GeXin No.1) and its ability to assimilate external phytate-P. Whereas phytase activities in roots, shoots and growth media of P i-fed 14-day-old seedlings were only 1.3-4.9% of total acid phosphatase (APase) activities, P starvation triggered an increase in phytase secretion up to 914.9 mU mg -1 protein, equivalent to 18.2% of total APase activities. Much of the extracellular phytase activities were found to be root-associated than root-released. The plants were not able to utilize phytate adsorbed to sand, except when insoluble phytate salts were preformed with Mg 2+ and Ca 2+ ions for supplementation. Tobacco grew better in sand supplemented with Mg-phytate salts (31.9 mg dry weight plant -1; 0.68% w/w P concentration) than that with Ca-phytate salts (9.5 mg plant -1; 0.42%), presumably due to its higher solubility. We conclude that insolubility of soil phytate is the major constrain for its assimilation. Improving solubility of soil phytate, for example, by enhancement of citrate secretion, may be a feasible approach to improve soil phytate assimilation. © Springer 2006.postprin

Impact of baseline and newly acquired conduction disorders on need for permanent pacemakers with 3 consecutive generations of self-expanding transcatheter aortic heart valves

Introductions: We aimed to compare conduction dynamics and need for permanent pacemaker implantation (PPI) after CoreValve, Evolut R and PRO (transcatheter aortic valve replacement (TAVR)). Methods: Patients were stratified based on conduction at baseline; Cohort A had normal conduction, Cohort B had conduction abnormalities including atrioventricular (AV)-block, fascicular block or complete bundle branch block. Three different dynamic QRS-patterns were defined: stable QRS-duration, transient QRS-prolongation and persistent QRS-prolongation. We performed multivariable regression analysis to estimate the effect of the three separate transcatheter heart valves (THV's) on need for PPI at 30 days. Results: TAVR was performed with CoreValve (N = 113), Evolut R (N = 157) or Evolut PRO (N = 92). Conduction dynamics were similar between the different THVs. Overall, Evolut R and PRO showed a tendency towards less PPI compared to CoreValve (17% vs. 19% vs. 27%, P = 0.08), which was driven by a lower PPI rate in Cohort A (6% vs. 11% vs. 25%, P = 0.002). Need for PPI was restricted to patients with persistent QRS-prolongation in Cohort A (26/106) but did not correlate with conduction dynamics in Cohort B. In multivariable logistic regression analysis the use of Evolut R (OR 0.38, 95% CI 0.19–0.78, P = 0.008) and PRO (OR 0.41, 95% CI 0.19–0.91, P-value = 0.028) were independently associated with less need for PPI. Conclusion: The newer generations Evolut R and PRO were associated with less PPI compared to CoreValve. Acquired persistent conduction abnormalities predicted PPI after TAVR only in patients with normal conduction at baseline. Our findings may help identify eligible patients for early discharge after Evolut R/PRO TAVR

Etude du métayage à partir de quelques exploitations choisies au sein d'une commune

[eng] In its present form, share tenancy tend to disappear. A limited survey shows the modifications operated on this kind of indirect farming. These modifications stimulate the owners to invest, to change the salary of the share tenant and his family and to realize another form of association of capital and labour. [fre] Sous sa forme actuelle, le métayage tend à disparaître. Une enquête limitée montre quelles sont les modifications apportées à ce mode de faire-valoir. Elles amènent les propriétaires à investir davantage, à modifier la rémunération du métayer et de sa famille, à réaliser une autre forme d'association capital-travail.

Transcription des noms indigènes sur les cartes d’Afrique du Nord

Maugenest J. Transcription des noms indigènes sur les cartes d’Afrique du Nord. In: Onomastica. Revue Internationale de Toponymie et d'Anthroponymie, 2e année N°2, juin 1948. Deuxième congrès international de toponymie et d'anthroponymie (3e et dernière série) pp. 147-151