25 research outputs found
Potential of Airborne LiDAR Derived Vegetation Structure for the Prediction of Animal Species Richness at Mount Kilimanjaro
The monitoring of species and functional diversity is of increasing relevance for the development of strategies for the conservation and management of biodiversity. Therefore, reliable estimates of the performance of monitoring techniques across taxa become important. Using a unique dataset, this study investigates the potential of airborne LiDAR-derived variables characterizing vegetation structure as predictors for animal species richness at the southern slopes of Mount Kilimanjaro. To disentangle the structural LiDAR information from co-factors related to elevational vegetation zones, LiDAR-based models were compared to the predictive power of elevation models. 17 taxa and 4 feeding guilds were modeled and the standardized study design allowed for a comparison across the assemblages. Results show that most taxa (14) and feeding guilds (3) can be predicted best by elevation with normalized RMSE values but only for three of those taxa and two of those feeding guilds the difference to other models is significant. Generally, modeling performances between different models vary only slightly for each assemblage. For the remaining, structural information at most showed little additional contribution to the performance. In summary, LiDAR observations can be used for animal species prediction. However, the effort and cost of aerial surveys are not always in proportion with the prediction quality, especially when the species distribution follows zonal patterns, and elevation information yields similar results
CropPol: a dynamic, open and global database on crop pollination
Seventy five percent of the world's food crops benefit from insect pollination. Hence, there has been increased interest in how global change drivers impact this critical ecosystem service. Because standardized data on crop pollination are rarely available, we are limited in our capacity to understand the variation in pollination benefits to crop yield, as well as to anticipate changes in this service, develop predictions, and inform management actions. Here, we present CropPol, a dynamic, open and global database on crop pollination. It contains measurements recorded from 202 crop studies, covering 3,394 field observations, 2,552 yield measurements (i.e. berry weight, number of fruits and kg per hectare, among others), and 47,752 insect records from 48 commercial crops distributed around the globe. CropPol comprises 32 of the 87 leading global crops and commodities that are pollinator dependent. Malus domestica is the most represented crop (32 studies), followed by Brassica napus (22 studies), Vaccinium corymbosum (13 studies), and Citrullus lanatus (12 studies). The most abundant pollinator guilds recorded are honey bees (34.22% counts), bumblebees (19.19%), flies other than Syrphidae and Bombyliidae (13.18%), other wild bees (13.13%), beetles (10.97%), Syrphidae (4.87%), and Bombyliidae (0.05%). Locations comprise 34 countries distributed among Europe (76 studies), Northern America (60), Latin America and the Caribbean (29), Asia (20), Oceania (10), and Africa (7). Sampling spans three decades and is concentrated on 2001-05 (21 studies), 2006-10 (40), 2011-15 (88), and 2016-20 (50). This is the most comprehensive open global data set on measurements of crop flower visitors, crop pollinators and pollination to date, and we encourage researchers to add more datasets to this database in the future. This data set is released for non-commercial use only. Credits should be given to this paper (i.e., proper citation), and the products generated with this database should be shared under the same license terms (CC BY-NC-SA). This article is protected by copyright. All rights reserved
Saturation par les mobilités : vers de nouvelles inégalités temporelles face aux rythmes de vie contemporains
Le temps est désormais une ressource rare dans un monde marqué par l’injonction à l’activité. Des formes de vulnérabilités temporelles apparaissent et l’écart se creuse entre les personnes capables de s’acheter du temps et celles qui n’ont d’autres choix que de le subir. La figure du businessman, de l’entrepreneur et finalement du winner est associée à un agenda bien rempli, so busy. Cet agenda chargé, annoté, raturé et flexible constitue l’un des symboles de la réussite sociale contemporaine. De l’autre côté, l’agenda social et culturel est aussi bien rempli. Aller voir la dernière expo, dîner chez des amis et assurer au footing du dimanche matin s’inscrivent dans les tâches à remplir après une semaine de travail déjà bien chargée. A une autre échelle temporelle, il faudra aussi organiser les week-ends de mai et les vacances d’été. Le culte de la performance, la volonté de rester dans la course amène les individus à s’organiser des rythmes de vie toujours plus complexes. Le rythme de vie est devenu une figure esthétique du soi . Cette esthétique temporelle touche le plus souvent les classes les mieux dotées économiquement qui l’acceptent et l’entendent comme un style de vie qui donne à vivre pleinement. D’autres segments de la population sont aussi touchés par des rythmes de vie particulièrement soutenus comme les familles composées d’un couple biactif avec des enfants. Dans cette configuration, le rythme serait davantage subi et amènerait les individus à devoir composer avec d’importantes pressions temporelles. Ce chapitre entend faire le point sur les rythmes de vie contemporains et la saturation des temps. Il prend comme objet la mobilité qui est marquée par des formes d’injonctions multiples. Il s’agit d’abord de rediscuter des approches critiques du temps ; ensuite, à partir de recherches récentes sur les grands mobiles en Europe et des résultats les plus saillants d’une enquête menée auprès d’une vingtaine de familles, le chapitre propose de mettre en lumière la notion de vulnérabilité temporelle et les inégalités qu’elle préfigure
Prediction of emergency department patient disposition decision for proactive resource allocation for admission.
We investigate the capability of information from electronic health records of an emergency department (ED) to predict patient disposition decisions for reducing boarding delays through the proactive initiation of admission processes (e.g., inpatient bed requests, transport, etc.). We model the process of ED disposition decision prediction as a hierarchical multiclass classification while dealing with the progressive accrual of clinical information throughout the ED caregiving process. Multinomial logistic regression as well as machine learning models are built for carrying out the predictions. Utilizing results from just the first set of ED laboratory tests along with other prior information gathered for each patient (2.5 h ahead of the actual disposition decision on average), our model predicts disposition decisions with positive predictive values of 55.4%, 45.1%, 56.9%, and 47.5%, while controlling false positive rates (1.4%, 1.0%, 4.3%, and 1.4%), with AUC values of 0.97, 0.95, 0.89, and 0.84 for the four admission (minor) classes, i.e., intensive care unit (3.6% of the testing samples), telemetry unit (2.2%), general practice unit (11.9%), and observation unit (6.6%) classes, respectively. Moreover, patients destined to intensive care unit present a more drastic increment in prediction quality at triage than others. Disposition decision classification models can provide more actionable information than a binary admission vs. discharge prediction model for the proactive initiation of admission processes for ED patients. Observing the distinct trajectories of information accrual and prediction quality evolvement for ED patients destined to different types of units, proactive coordination strategies should be tailored accordingly for each destination unit
Skeletal muscle vasodilatation during sympathoexcitation is not neurally mediated in humans
Evidence for the existence of sympathetic vasodilator nerves in human skeletal muscle is controversial. Manoeuvres such as contralateral ischaemic handgripping to fatigue that cause vasoconstriction in the resting forearm evoke vasodilatation after local α-adrenergic receptor blockade, raising the possibility that both constrictor and dilator fibres are present. The purpose of this study was to determine whether this dilatation is neurally mediated.Ten subjects (3 women, 7 men) performed ischaemic handgripping to fatigue before and after acute local anaesthetic block of the sympathetic nerves (stellate ganglion) innervating the contralateral (resting) upper extremity. Forearm blood flow was measured with venous occlusion plethysmography in the resting forearm.In control studies there was forearm vasoconstriction during contralateral handgripping to fatigue. During contralateral handgripping after stellate block, blood flow in the resting forearm increased from 6.1 ± 0.7 to 18.7 ± 2.2 ml dl−1 min−1 (P < 0.05). Mean arterial pressure measured concurrently increased from ≈90 to 130 mmHg and estimated vascular conductance rose from 6.5 ± 0.7 to 14.0 ± 1.5 units, indicating that most of the rise in forearm blood flow was due to vasodilatation.Brachial artery administration of β-blockers (propranolol) and the nitric oxide (NO) synthase inhibitor NG-monomethyl-L-arginine (L-NMMA) after stellate block virtually eliminated all of the vasodilatation to contralateral handgrip.Since vasodilatation was seen after stellate block, our data suggest that sympathetic dilator nerves are not responsible for limb vasodilatation seen during sympathoexcitation evoked by contralateral ischaemic handgripping to fatigue. The results obtained with propranolol and L-NMMA suggest that β-adrenergic mechanisms and local NO release contribute to the dilatation
Plant and animal functional diversity drive mutualistic network assembly across an elevational gradient
Differential responses of plant and animal functional diversity to climatic variation could affect trait matching in mutualistic interactions. Here, Albrecht et al. show that network structure varies across an elevational gradient owing to bottom-up and top-down effects of functional diversity
Plant and animal functional diversity drive mutualistic network assembly across an elevational gradient
Species' functional traits set the blueprint for pair-wise interactions in ecological networks. Yet, it is unknown to what extent the functional diversity of plant and animal communities controls network assembly along environmental gradients in real-world ecosystems. Here we address this question with a unique dataset of mutualistic bird-fruit, bird-flower and insect-flower interaction networks and associated functional traits of 200 plant and 282 animal species sampled along broad climate and land-use gradients on Mt. Kilimanjaro. We show that plant functional diversity is mainly limited by precipitation, while animal functional diversity is primarily limited by temperature. Furthermore, shifts in plant and animal functional diversity along the elevational gradient control the niche breadth and partitioning of the respective other trophic level. These findings reveal that climatic constraints on the functional diversity of either plants or animals determine the relative importance of bottom-up and top-down control in plant-animal interaction networks
Structure and Dynamics of a Compact State of a Multidomain Protein, the Mercuric Ion Reductase
The functional efficacy of colocalized, linked protein domains is dependent on linker flexibility and system compaction. However, the detailed characterization of these properties in aqueous solution presents an enduring challenge. Here, we employ a novel, to our knowledge, combination of complementary techniques, including small-angle neutron scattering, neutron spin-echo spectroscopy, and all-atom molecular dynamics and coarse-grained simulation, to identify and characterize in detail the structure and dynamics of a compact form of mercuric ion reductase (MerA), an enzyme central to bacterial mercury resistance. MerA possesses metallochaperone-like N-terminal domains (NmerA) tethered to its catalytic core domain by linkers. The NmerA domains are found to interact principally through electrostatic interactions with the core, leashed by the linkers so as to subdiffuse on the surface over an area close to the core C-terminal Hg(II)-binding cysteines. How this compact, dynamical arrangement may facilitate delivery of Hg(II) from NmerA to the core domain is discussed