Basal levels and diurnal variations of some hormones and metabolites in blood of dairy cows treated daily with rbst in early and late lactation

The variations of basal value (before morning feeding at 3-4 days interval) and daily pattern (on 4and 18day of treat- ment with 8 blood collections within 24h) of hormones and metabolites were studied in four dairy cows; 2 in early and 2 in late lactation, which were alternatively injected daily for a period of 21 days with 26.3 mg rbST or saline. The rbST injection significantly increased the basal and daily levels of GH, IGF-I in both stages of lactation. Daily levels of NEFA were significantly increased by rbST in both stages of lactation and their variations, due to the effect of meals, were coun- teracted by the rbST; the higher level of NEFA allowed a greater sparing of glucose, the blood level of which resulted higher (P<0.05) in late lactation (mainly for less lactose yield), as well as a sparing of amino acid that resulted in a lower blood urea level (P<0.05, only in late lactation). Moreover, these metabolic changes in late lactating cows, and in par- ticular the high availability of glucose, determined a significantly higher blood level of insulin and T3, and lower level of glucagon. Despite the similar GH, IGF-I and NEFA increases observed in the cows treated in early and late lactation, other metabolic and endocrine consequences resulted more evident in late lactation. Furthermore, some of these variations were affected by the forage meals. It can be concluded, therefore, that the changes occurring in the blood subsequent to a rbST treatment are not equal to those which occur at the start of lactation; moreover, they are affected by the daily feeding pattern and perhaps by the stage of lactation

Comparing the reflectivity of ungrouped carbonaceous chondrites with that of short period comets like 2P/Encke

Aims. The existence of asteroid complexes produced by the disruption of these comets suggests that evolved comets could also produce high-strength materials able to survive as meteorites. We chose as an example comet 2P/Encke, one of the largest object of the so-called Taurid complex. We compare the reflectance spectrum of this comet with the laboratory spectra of some Antarctic ungrouped carbonaceous chondrites to investigate whether some of these meteorites could be associated with evolved comets. Methods. We compared the spectral behaviour of 2P/Encke with laboratory spectra of carbonaceous chondrites. Different specimens of the common carbonaceous chondrite groups do not match the overall features and slope of comet 2P/Encke. Trying anomalous carbonaceous chondrites, we found two meteorites, Meteorite Hills 01017 and Grosvenor Mountains 95551, which could be good proxies for the dark materials forming this short-period comet. We hypothesise that these two meteorites could be rare surviving samples, either from the Taurid complex or another compositionally similar body. In any case, it is difficult to get rid of the effects of terrestrial weathering in these Antarctic finds, and further studies are needed. Future sample return from the so-called dormant comets could be also useful to establish a ground truth on the materials forming evolved short-period comets. Results. As a natural outcome, we think that identifying good proxies of 2P/Encke-forming materials might have interesting implications for future sample-return missions to evolved, potentially dormant or extinct comets. To understand the compositional nature of evolved comets is particularly relevant in the context of the future mitigation of impact hazard from these dark and dangerous projectiles.Comment: Accepted for publication in A&A on July 6, 202

Observation of aerodynamic instability in the flow of a particle stream in a dilute gas

Forming macroscopic solid bodies in circumstellar discs requires local dust concentration levels significantly higher than the mean. Interactions of the dust particles with the gas must serve to augment local particle densities, and facilitate growth past barriers in the metre size range. Amongst a number of mechanisms that can amplify the local density of solids, aerodynamic streaming instability (SI) is one of the most promising. This work tests the physical assumptions of models that lead to SI in protoplanetary disks (PPDs). We conduct laboratory experiments in which we track the three-dimensional motion of spherical solid particles fluidized in a low-pressure, laminar, incompressible, gas stream. The particle sizes span the Stokes-Epstein drag regime transition and the overall dust-to-gas mass density ratio is close to unity. Lambrechts et al. (2016) established the similarity of the laboratory flow to a simplified PPD model flow. We obtain experimental results suggesting an instability due to particle-gas interaction: i) there exist variations in particle concentration in the direction of the mean drag forces; ii) the particles have a tendency to 'catch up' to one another when they are in proximity; iii) particle clumping occurs on very small scales, which implies local enhancements above the background dust-to-gas mass density ratio by factors of several tens; v) the presence of these density enhancements occurs for a mean dust-to-gas mass density ratio approaching or greater than 1; v) we find evidence for collective particle drag reduction when the local particle number density becomes high and when the background gas pressure is high so that the drag is in the continuum regime. The experiments presented here are precedent-setting for observing SI under controlled conditions and may lead to a deeper understanding of how it operates in nature.Comment: Accepted for publication in A&A; abstract abridged for arXi

Asteroid Ryugu before the Hayabusa2 encounter

Asteroid (162173) Ryugu is the target object of Hayabusa2, an asteroid exploration and sample return mission led by Japan Aerospace Exploration Agency (JAXA). Ground-based observations indicate that Ryugu is a C-type near-Earth asteroid with a diameter of less than 1 km, but the knowledge of its detailed properties is very limited prior to Hayabusa2 observation. This paper summarizes our best understanding of the physical and dynamical properties of Ryugu based on ground-based remote sensing and theoretical modeling before the Hayabusa2’s arrival at the asteroid. This information is used to construct a design reference model of the asteroid that is used for the formulation of mission operation plans in advance of asteroid arrival. Particular attention is given to the surface properties of Ryugu that are relevant to sample acquisition. This reference model helps readers to appropriately interpret the data that will be directly obtained by Hayabusa2 and promotes scientific studies not only for Ryugu itself and other small bodies but also for the solar system evolution that small bodies shed light on.Additional co-authors: Guy Libourel, Roy Lichtenheldt, Alessandro Maturilli, Scott R. Messenger, Tatsuhiro Michikami, Hideaki Miyamoto, Stefano Mottola, Thomas Müller, Akiko M. Nakamura, Larry R. Nittler, Kazunori Ogawa, Tatsuaki Okada, Ernesto Palomba, Naoya Sakatani, Stefan E. Schröder, Hiroki Senshu, Driss Takir, Michael E. Zolensky and International Regolith Science Group (IRSG) in Hayabusa2 projec

Toward a methodical framework for comprehensively assessing forest multifunctionality

Biodiversity-ecosystem functioning (BEF) research has extended its scope from communities that are short-lived or reshape their structure annually to structurally complex forest ecosystems. The establishment of tree diversity experiments poses specific methodological challenges for assessing the multiple functions provided by forest ecosystems. In particular, methodological inconsistencies and nonstandardized protocols impede the analysis of multifunctionality within, and comparability across the increasing number of tree diversity experiments. By providing an overview on key methods currently applied in one of the largest forest biodiversity experiments, we show how methods differing in scale and simplicity can be combined to retrieve consistent data allowing novel insights into forest ecosystem functioning. Furthermore, we discuss and develop recommendations for the integration and transferability of diverse methodical approaches to present and future forest biodiversity experiments. We identified four principles that should guide basic decisions concerning method selection for tree diversity experiments and forest BEF research: (1) method selection should be directed toward maximizing data density to increase the number of measured variables in each plot. (2) Methods should cover all relevant scales of the experiment to consider scale dependencies of biodiversity effects. (3) The same variable should be evaluated with the same method across space and time for adequate larger-scale and longer-time data analysis and to reduce errors due to changing measurement protocols. (4) Standardized, practical and rapid methods for assessing biodiversity and ecosystem functions should be promoted to increase comparability among forest BEF experiments. We demonstrate that currently available methods provide us with a sophisticated toolbox to improve a synergistic understanding of forest multifunctionality. However, these methods require further adjustment to the specific requirements of structurally complex and long-lived forest ecosystems. By applying methods connecting relevant scales, trophic levels, and above? and belowground ecosystem compartments, knowledge gain from large tree diversity experiments can be optimized

Review of factors influencing the success or failure of biocontrol: technical, industrial and socio-economic perspectives

Communication orale au 11. IOBC-WPRS Meeting of the working group "Biological control of fungal and bacterial plant pathogens". Climate change: challenge or threat to biocontrol?, 2010/06/07-11 ; Graz (AUT).International audienceAlthough their role in plant health management is still quite modest, ever increasing expectations are placed on biocontrol agents for the complementation or replacement of pesticide use. Despite decades of research and more than 12,000 scientific papers on biological control of plant diseases, little more than 14 microbe-based commercial products are presently registered for use against diseases in the European Union. Through a review of published scientific literature, economic and market analyses and a survey of 675 farmers in 9 European countries, difficulties and conditions for success have been identified. The most salient features and future outlook are presented in terms of scientific/technical aspects, production costs and return on investment as well as (somewhat unexpected) factors deemed to be most influential on the evolution of the biocontrol market in the coming decades