6,812 research outputs found
Prey capture and meat-eating by the wild colobus monkey _Rhinopithecus bieti_ in Yunnan, China
If it is true that extant primates evolved from an insectivorous ancestor, then primate entomophagy would be a primitive trait. Many taxa, however, have undergone a dietary shift from entomophagy to phytophagy, evolving a specialised gut and dentition and becoming exclusive herbivores. The exclusively herbivorous taxa are the Malagasy families Indriidae and Lepilemuridae, and the Old World Monkey subfamily Colobinae, and among these meat-eating has not been observed except as an anomaly, with the sole exception of the Hanuman langur (_Semnopithecus entellus_), which feeds on insects seasonally, and a single observation of a nestling bird predated by wild Sichuan snub-nosed monkeys (_Rhinopithecus roxellana_). Here, we describe the regular capture of warm-blooded animals and the eating of meat by a colobine, the critically endangered Yunnan snub-nosed monkey (_Rhinopithecus bieti_). This monkey engages in scavenge hunting as a male-biased activity that may, in fact, be related to group structure and spatial spread. In this context, meat-eating can be regarded as an energy/nutrient maximization feeding strategy rather than as a consequence of any special characteristic of meat itself. The finding of meat-eating in forest-dwelling primates might provide new insights into the evolution of dietary habits in early humans
Clapeyron equation and phase equilibrium properties in higher dimensional charged topological dilaton AdS black holes with a nonlinear source
Using Maxwell's equal area law, we discuss the phase transition of higher
dimensional charged topological dilaton AdS black holes with a nonlinear
source. The coexisting region of the two phases is found and we depict the
coexistence region in diagrams. The two-phase equilibrium curves in
diagrams are plotted, and we take the first order approximation of volume
in the calculation. To better compare with a general thermodynamic system, the
Clapeyron equation is derived for higher dimensional charged topological black
hole with a nonlinear source. The latent heat of isothermal phase transition is
investigated. We also study the effect of the parameters of the black hole on
the region of two-phases coexistence. The results show that the black hole may
go through a small-large phase transition similar to those of usual non-gravity
thermodynamic systems.Comment: 21 pages,25 figures. published version in EPJC. arXiv admin note:
substantial text overlap with arXiv:1411.7202; text overlap with
arXiv:1506.01786, arXiv:hep-th/0605042 by other author
Thermodynamics of phase transition in higher dimensional Reissner-Nordstr\"{o}m-de Sitter black hole
It is well known that there are black hole and the cosmological horizons for
the Reissner-Nordstr\"{o}m-de Sitter spacetime. Although the thermodynamic
quantities on the horizons are not irrelevant, they satisfy the laws of black
hole thermodynamics respectively. In this paper by considering the relations
between the two horizons we give the effective thermodynamic quantities in
-dimensional Reissner-Nordstr\"{o}m-de Sitter spacetime. The
thermodynamic properties of these effective quantities are analyzed, moreover,
the critical temperature, critical pressure and critical volume are obtained.
We carry out an analytical check of Ehrenfest equations and prove that both
Ehrenfest equations are satisfied. So the spacetime undergoes a second order
phase transition at the critical point. This result is consistent with the
nature of liquid--gas phase transition at the critical point, hence deepening
the understanding of the analogy of charged dS spacetime and liquid--gas
systems.Comment: 18 pages, 7 figures, 1 tabl
Phase transition of the higher dimensional charged Gauss-Bonnet black hole in de Sitter spacetime
We study the phase transition of charged Gauss-Bonnet-de Sitter (GB-dS) black
hole. For black holes in de Sitter spacetime, there is not only black hole
horizon, but also the cosmological horizon. The thermodynamic quantities on the
both horizons satisfy the first law of the black hole thermodynamics,
respectively; moreover, there are additional connections between them. Using
the effective temperature approach, we obtained the effective thermodynamic
quantities of charged GB-dS black hole. According to Ehrenfest classification,
we calculate some response functions and plot their figures, from which one can
see that the spacetime undergoes a second-order phase transition at the
critical point. It is shown that the critical values of effective temperature
and pressure decrease with the increase of the value of GB parameter .Comment: 9 pages, 16 figure
Short-Chain Fatty Acid Propionate Alleviates Akt2 Knockout-Induced Myocardial Contractile Dysfunction
Background and Aims. Dysregulation of Akt has been implicated in diseases such as cancer and diabetes, although little is known about the role of Akt deficiency on cardiomyocyte contractile function. This study was designed to examine the effect of Akt2 knockout-induced cardiomyocyte contractile response and the effect of dietary supplementation of short-chain fatty acid propionate on Akt2 knockout-induced cardiac dysfunction, if any. Methods and Results. Adult male wild-type (WT) and Akt2 knockout mice were treated with propionate (0.3 g/kg, p.o.) or vehicle for 7 days. Oral glucose tolerance test (OGTT) was performed. Cardiomyocyte contractile function and mitochondrial membrane potential were assessed. Expression of insulin-signaling molecules Akt, PTEN, GSK3β, and eNOS receptors for short-chain fatty acids GPR41, and GPR43 as well as protein phosphatase PP2AA, PP2AB, PP2C were evaluated using Western blot analysis. Our results revealed that Akt2 knockout led to overt glucose intolerance, compromised cardiomyocyte contractile function (reduced peak shortening and maximal velocity of shortening/relengthening as well as prolonged relengthening), loss of mitochondrial membrane potential, decreased GPR41 and elevated GPR43 expression, all of which, with the exception of glucose intolerance and elevated GPR43 level, were significantly attenuated by propionate. Neither Akt2 knockout nor propionate affected the expression of protein phosphatases, eNOS, pan, and phosphorylated PTEN and GSK3β. Conclusions. Taken together, these data depicted that Akt2 knockout may elicit cardiomyocyte contractile and mitochondrial defects and a beneficial role of propionate or short-chain fatty acids against Akt2 deficiency-induced cardiac anomalies
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