Alimentation et activité d’un groupe de chimpanzés réintroduits en forêt Gabonaise

In 1968 and 1969, a group of free-ranging Chimpanzees, Pan troglodytes troglodytes, was introduced onto an island of the Ipassa Reserve (fig. 2), near Makokou, Gabon. Observations of this group during one year (1971/1972) allowed the author to collect precise data about their feeding behaviour in a natural environment and to make quantitative estimates of the composition of diet

Isolation and characterization of pentadin, the sweet principle of Pentadiplandra brazzeana Baillon

An aqaeous extract from the pulp of the plant Pentadiplandra brazzeana Baillon (Pentadiplandraceae) yielded a strong sweet-tasting material. This sweet principle was isolated by water extraction, ultrafiltration and gel filtration. The conclusion that this substance must be of a proteinaceous nature was based on amino acid analysis, characteristic UV-absorption spectrum and positive colour reaction with Coomassie brilliant blue. The mol. wt of the subunit of the sweet protein was estimated to be ˜ 12 000 daltons. The sweetness intensity of the whole protein was ˜ 500 times that of sucrose on a weight basis. The taste response in a Rhesus monkey to a 0.1 % solution was comparable to the response to a 0.02 % monellin solution. We propose the name ‘pentadin' for this sweet-tasting protein and present a few comments about the possible origin of such sugar mimic

On the relationship between sweet taste and seasonal body weight changes in a primate (Microcebus murinus)

The relationship between obesity and taste, especially sweet taste, has been and is of interest. From this point of view of a small primate, the lesser mouse lemur (Microcebus murinus), is of particular interest. It goes through a yearly cycle of physiological changes, one of which is an extreme variation in body weight of up to 100%. This occurs concomitantly with significant changes of the animal's liking for sucrose; measured by two-bottle preference tests, the threshold for sucrose changes from 28-45 in lean to 77-105 mM in obese animals. It is possible that a change in peripheral taste sensitivity might be the cause for these preference changes. To test this possibility we studied the ability of M.murinus to taste sucrose with electrophysiological and conditioned taste aversion techniques. The electrophysiological recordings were obtained from the chorda tympani proper nerve in two heavy and three lean animals. We did not record any difference between the two groups in their neural response to a series of sucrose concentrations. Conditioned taste aversion experiments with 200 mM sucrose as conditioning stimulus and 50 and 200 mM sucrose as test stimuli gave similar results. No difference was found between three heavy and four lean animals; both groups rejected the sucrose concentrations. The results support the notion that the seasonal variations in preference threshold to sucrose were unrelated to the ability of M.murinus to taste sucros

On the sense of taste in two Malagasy Primates (Microcebus murinus and Eulemur mongoz)

The relationship between phylogeny and taste is of growing interest. In this study we present recordings from the chorda tympani proper (CT) nerve of two lemuriforme primates, the lesser mouse lemur (Microcebus murinus) and the mongoose lemur (Eulemur mongoz), to an array of taste stimuli which included the sweeteners acesulfame-K, alitame, aspartame, D-glucose, dulcin, monellin, neohesperidin dihydrochalcone (NHDHC), saccharin, sodium superaspartame, stevioside, sucralose (TGS), sucrose, suosan, thaumatin and xylitol, as well as the non-sweet stimuli NaC1, citric acid, tannin and quinine hydrochloride. In M.murinus the effects of the taste modifiers gymnemic acid and miraculin on the CT response were recorded. Conditioned taste aversion (CTA) experiments in M.murinus and two-bottle preference (TBP) tests in E.mongoz were also conducted. We found that all of the above tastants except thaumatin elicited a CT response in both species. The CTA technique showed that M.murinus generalized from sucrose to monellin but not to thaumatin. The intake of aspartame, ranging in concentration from 0.1 to 30 mM was measured in E.mongoz with TBP tests. At no concentration did we see a preference, but there was a significant rejection of 10 and 30 mM aspartame (P←0.025). Miraculin had no effects on the CT response to acids, and gymnemic acid did not selectively suppress the CT response to sucrose or that of any other sweeteners. The absence of ability to taste thaumatin in these species supports the dichotomy between catarrhine and non-catarrhine species. The difference in results with thaumatin and monellin indicate that their sweet moieties are not identical. It also points to a phylogenetic difference in taste within the prosimian group. Further, the results with aspartame indicate that the perception of sweetness from aspartame is limited to catarrhine species. Finally, neither miraculin nor gymnemic acid exhibit the same taste modifying effects in lemuriformes as they do in hominoidea. Thus the results with gymnemic acid and miraculin corroborate those obtained earlier in other prosimian

Les mammifères frugivores arboricoles nocturnes d'une forêt guyanaise : inter-relations plantes-animaux

The relationships between a community of nine nocturnal frugivorous mammal species and the plants on which they feed were studied during 14 consecutive months in a secondary forest near Cayenne, French Guiana. Two major trophic groups can be defined : 1. - The seed eaters, which open unripe fruits to eat their seeds. All are rodents : Coendou prehensilis (average adult weight 4 000 g), Echimys armatus (400 g) and Oryzomys concolor (35 g). 2. - The pulp eaters, which specialize in ripe fruits. They eat the pulp and swallow most of the seeds which are disseminated with their feces. Five of them are marsupials : Didelphis marsupialis (1 000 g), Philander opossum (400 g), Caluromys philander (300 g), Marmosa cinerea (80 g) and Marmosa murina (45 g). The sixth species is a Procyonid Carnivore : Potos flavus (3 000 g). These differing types of feeding strategies are discussed in relation to the morphology of the teeth and digestive tract of the species. Species with a similar diet and comparable body size generally live in different forest layers. The population density and biomass of these nocturnal frugivorous mammals were estimated on the basis of direct counts along forest trails at night, trapping results and radio-tracking. Out of the 127 plant species listed, 26 play a major role as a food source for the mammals studied. The trunk diameter (DBH) of the 13 most common species was measured, and the distribution of these trees mapped in the 8.5 ha study area. These 13 tree species account for approximately half of the total basal area, which is considered here as an index of standing crop biomass. The same 13 species account for 25 % of the total number of individual trees. Fruit production was measured during 13 months by weighing all fallen fruits along 1 200 m of trails. Fruit production and consumption of the same species were also estimated by the use of fruit collectors located under fruiting trees. Special attention was given to the phenological cycles of trees. Three types of fruiting cycles could thus be related to three different foraging strategies of the sympatric frugivorous mammals : 1. - Species with a low fruit production spread over an extended time period. Only a few fruit ripen at the same time, but fruiting takes place almost all year long. Such trees are early - or late - pionneer species ; their fruits have tiny seeds which are mainly eaten by small vertebrates which scatter them more or less homogeneously. 2. - Species with synchronous, but irregular cycles of fruit production. Such trees have rather large seeds which are very attractive to seed-eating rodents. These animals even destroy part of the fruit crop before ripening. The massive, irregular, and unpredictable fruiting cycles of these species may reduce seed predation by rodents . The few trees belonging to this category which do not bear fruit synchronously with their conspecifics may have their crop totally destroyed by rodents. 3. - Species with synchronous and regular cycles of fruit production. Such trees have rather large seeds, which are ingested by large frugivorous vertebrates and spread through their feces. Chemical or physical deterrents are generally present in such fruits before ripening. The tree species belonging to this category have successive and partly overlapping periods of fruit production. In this way, food is made available for pulp-eaters during most of the year. This pattern of fructification is presumably the end-result of a long lasting mutual interaction between plants and seed-scattering vertebrales. Frugivorous mammals apparently need two different kinds of fruit in their diet, sorne rich in sugar and others rich in fat. Trees producing these two categories of fruit produce their crop successively, so that the necess ary nutrients are made available throughout the year. A definite decrease in fruit production takes place in our study are ajust before the beginning of the dry season. The marsupial pulp-eaters have adapted to this temporary food shortage by storing fat during the season of plenty. However, their production of young is strongly affected by this seasonal food shortage, as shawn by an increased mortality rate of pouch young

Measurement of the cross section for isolated-photon plus jet production in pp collisions at √s=13 TeV using the ATLAS detector

The dynamics of isolated-photon production in association with a jet in proton–proton collisions at a centre-of-mass energy of 13 TeV are studied with the ATLAS detector at the LHC using a dataset with an integrated luminosity of 3.2 fb−1. Photons are required to have transverse energies above 125 GeV. Jets are identified using the anti- algorithm with radius parameter and required to have transverse momenta above 100 GeV. Measurements of isolated-photon plus jet cross sections are presented as functions of the leading-photon transverse energy, the leading-jet transverse momentum, the azimuthal angular separation between the photon and the jet, the photon–jet invariant mass and the scattering angle in the photon–jet centre-of-mass system. Tree-level plus parton-shower predictions from Sherpa and Pythia as well as next-to-leading-order QCD predictions from Jetphox and Sherpa are compared to the measurements

A search for resonances decaying into a Higgs boson and a new particle X in the XH → qqbb final state with the ATLAS detector

A search for heavy resonances decaying into a Higgs boson (H) and a new particle (X) is reported, utilizing 36.1 fb−1 of proton–proton collision data at collected during 2015 and 2016 with the ATLAS detector at the CERN Large Hadron Collider. The particle X is assumed to decay to a pair of light quarks, and the fully hadronic final state is analysed. The search considers the regime of high XH resonance masses, where the X and H bosons are both highly Lorentz-boosted and are each reconstructed using a single jet with large radius parameter. A two-dimensional phase space of XH mass versus X mass is scanned for evidence of a signal, over a range of XH resonance mass values between 1 TeV and 4 TeV, and for X particles with masses from 50 GeV to 1000 GeV. All search results are consistent with the expectations for the background due to Standard Model processes, and 95% CL upper limits are set, as a function of XH and X masses, on the production cross-section of the resonance

Combination of searches for Higgs boson pairs in pp collisions at \sqrts = 13 TeV with the ATLAS detector

This letter presents a combination of searches for Higgs boson pair production using up to 36.1 fb(-1) of proton-proton collision data at a centre-of-mass energy root s = 13 TeV recorded with the ATLAS detector at the LHC. The combination is performed using six analyses searching for Higgs boson pairs decaying into the b (b) over barb (b) over bar, b (b) over barW(+)W(-), b (b) over bar tau(+)tau(-), W+W-W+W-, b (b) over bar gamma gamma and W+W-gamma gamma final states. Results are presented for non-resonant and resonant Higgs boson pair production modes. No statistically significant excess in data above the Standard Model predictions is found. The combined observed (expected) limit at 95% confidence level on the non-resonant Higgs boson pair production cross-section is 6.9 (10) times the predicted Standard Model cross-section. Limits are also set on the ratio (kappa(lambda)) of the Higgs boson self-coupling to its Standard Model value. This ratio is constrained at 95% confidence level in observation (expectation) to -5.0 &lt; kappa(lambda) &lt; 12.0 (-5.8 &lt; kappa(lambda) &lt; 12.0). In addition, limits are set on the production of narrow scalar resonances and spin-2 Kaluza-Klein Randall-Sundrum gravitons. Exclusion regions are also provided in the parameter space of the habemus Minimal Supersymmetric Standard Model and the Electroweak Singlet Model. For complete list of authors see http://dx.doi.org/10.1016/j.physletb.2019.135103</p