Oxytocin promotes social grooming in bonobos: testing the biobehavioural feedback loop hypothesis

Oxytocin has attracted research attention due to its role in promoting social bonding. One notable recent hypothesis is the biobehavioral feedback loop, which posits that the oxytocin system has evolved to support the formation and maintenance of social bonds through a positive feedback loop, where oxytocin promotes social behaviours which then cause oxytocin release themselves. In the two Pan species, humans’ closest relatives, oxytocin is known to be released following key behaviours related to social bonding, such as social grooming in chimpanzees and female-female sexual behaviour in bonobos. However, no experimental evidence has demonstrated that oxytocin promotes such socio-positive behaviours. To test this, we administered nebulized oxytocin or saline placebo to a group of female bonobos and subsequently observed the change in their gross behavior during free interaction. We found that bonobos groomed other group members significantly more frequently in the oxytocin compared to placebo condition. Other behavioural measures did not largely differ between conditions, except for a nonsignificant trend for reduction in abnormal regurgitation/reingestion behaviour. Overall, we found that oxytocin promoted socio-positive interaction in bonobos, providing support for the biobehavioural feedback loop hypothesis of oxytocin in bonobo social evolution.

Vibrational Dynamics of 2-[3-(p-flourobenzoyl) Propyl]-1,2,3,4,6,7,12,12, a-octahydropyrazino[2′,1&prime:6,1] Pyrido [3,4-b] Indole [centbutindole]: A Potent Nuroleptic Drug

FITR spectra and normal mode analysis of compound 2-[3-(p-flourobenzoyl)propyl]-1,2,3,4,6,7,12,12, a-octahydropyrazino[2′,1′:6,1] pyrido [3,4-b] indole [centbutindole], which is a potent nuroleptic drug and belong to a series of 2-substituted pyrazino-pyrido indoles. It also blind with 5HT2 receptors. It has shown good antihypotensive activity. The well known Wilson’s G-F matrix method with Urey-Bradely force field has been used to evaluate the normal mode frequencies of vibration. Good agreement has been obtain between them and a set of 29 force field constants is established. The vibrational dynamics of the title compound is being reported using Urey Bradley force field. It has shown acute toxicity, gross behavior and central effects like anti convulsant activity, anti reserpine activity and stereo specificity of action. The conformation of the title compound was determined by X-ray diffraction. It is planned to determine the conformation in such cases by the application of Fourier Transform Infrared (FITR) spectroscopy and normal mode analysis. As a first step in this direction the FITR spectrum of the title compound has been recorded and its normal mode analysis is carried out. The assignments of the frequencies are based on the theoretically calculated frequencies have also been given their best assignment.

Hybrid Modeling of Non-Linear Mechanical Systems: The Case of a Vehicle Shock Absorber

A large effort in the analysis of a physical system is the development of a model describing its behavior. The non-linear and time variant characteristic of many mechanical systems can be hardly represented by an analytical model without a remarkable increase of its complexity which contrasts with the need to obtain acceptable results in real-time such as in multibody simulations, system control design and Hardware in the loop (HIL) testing. In this context, the use of artificial neural networks are recognized as a powerful modeling tool to produce accurate model with reduced complexity. On the other hand their response to inputs outside the learning range may lead to unrealistic results. This paper presents an hybrid modeling technique, which combines a physical model with a neural network. The physical model describes the gross behavior of the system and the neural network captures the non-linear non-modeled behaviors or the effect of time-varying parameters. It is also proposed a method to limit the outside-range unpredicted responses. A RC car shock absorber is used as test case. Experimental results show that the neural network improves the physical model output capturing nonlinear aspects such as the hysteresis, the fluid leakage and the increase of its temperature.

Deletion of Ghrelin Impairs neither Growth nor Appetite

ABSTRACT Pharmacological studies show that ghrelin stimulates growth hormone release, appetite, and fat deposition, but ghrelin's physiological role in energy homeostasis has not been established. Ghrelin was also proposed to regulate leptin and insulin release and to be important for the normal function of stomach, heart, kidney, lung, testis, and placenta. To help determine a definable physiological role for ghrelin, we generated ghrelin-null mice. In contrast to predictions made from the pharmacology of ghrelin, ghrelin-null mice are not anorexic dwarfs; their size, growth rate, food intake, body composition, reproduction, gross behavior, and tissue pathology are indistinguishable from wild-type littermates. Fasting produces identical decreases in serum leptin and insulin in null and wild-type mice. Ghrelin-null mice display normal responses to starvation and diet-induced obesity. As in wild-type mice, the administration of exogenous ghrelin stimulates appetite in null mice. Our data show that ghrelin is not critically required for viability, fertility, growth, appetite, bone density, and fat deposition and not likely to be a direct regulator of leptin and insulin. Therefore, antagonists of ghrelin are unlikely to have broad utility as antiobesity agents.

Replacement of the glycoinositol phospholipid anchor of Drosophila acetylcholinesterase with a transmembrane domain does not alter sorting in neurons and epithelia but results in behavioral defects.

Drosophila has a single glycoinositol phospholipid (GPI)-anchored form of acetylcholinesterase (AChE) encoded by the Ace locus. To assess the role that GPI plays in the physiology, of AChE, we have replaced the wild-type GPI-AChE with a chimeric transmembrane form (TM-AChE) in the nervous system of the fly. Ace null alleles provided a genetic background completely lacking in endogenous GPI-AChE, and Ace minigene P transposon constructs were used to express both GPI- and TM-AChE forms in the tissues where AChE is normally expressed. Control experiments with the GPI-AChE minigene demonstrated a threshold between 9 and 12% of normal AChE activity for adult viability. Ace mutant flies were rescued by GPI-AChE minigene lines that expressed 12-40% of normal activity and were essentially unchanged from wild-type flies in behavior. TM-AChE minigene lines were able to rescue Ace null alleles, although with a slightly higher threshold than that for GPI-AChE. Although rescued flies expressing GPI-AChE at a level of 12% of normal activity were viable, flies expressing 13-16% of normal activity from the TM-AChE transgene died shortly after eclosion. Flies expressing TM-AChE at about 30% of normal levels were essentially unchanged from wild-type flies in gross behavior but had a reduced lifespan secondary to subtle coordination defects. These flies also showed reduced locomotor activity and performed poorly in a grooming assay. However, light level and electron microscopic immunocytochemistry showed no differences in the localization of GPI- and TM-AChE. Furthermore, endogenous and ectopic-induced expression of both AChEs in epithelial tissues of the adult and embryo, respectively, showed that they were sorted identically. Most epithelial cells sorted GPI- and TM-AChE to the apical surface, but cuticle-secreting epithelia sorted both proteins basolaterally. Our data suggest that rather than having a primary role in protein sorting, the GPI anchor or AChE plays some other more subtle cellular role in neuronal physiology.

Seismic hazard induced by mechanically interactive fault segments

This paper presents a phenomenological stochastic model for earthquake recurrence processes involving physical interaction among fault segments. Slip on one segment may reduce (or increase) the time to the next event on another segment or possibly induce an immediate slip on that segment as well. The gross behavior of this model is first observed through simulations; temporal and spatial disorder are observed even when the stochastic aspects are minimized. To estimate the strength of these interactions, we derive factors from the output of three-dimensional elastic dislocation analyses, relating induced stress changes to temporal changes in next-event dates. In a final section, we derive approximate analytical expressions and numerical results for future probabilistic earthquake risk and site hazard, conditional on the elapsed times since events on all relevant fault segments and on the number of events since that may have caused stress changes (interactions).

Spectral Classification of Composite Spectrum Stars

Classifying the spectral types of individual components of composite spectrum stars can be a difficult task. Markowitz (1969) discussed the problems of blended and veiled lines associated with the visual assessment of blue spectrograms. Although synthetic spectra (i.e. formed by the intentional superposition of two different spectra) can be used as a means of calibration, the classification of composites with slit spectrograms is a subjective process. Classifications based upon broad- and intermediate-band photometry (Young 1971) can be highly objective, but the lack of spectral resolution introduces other complications. For example, colors in the UBVR system measure the gross behavior of a star's energy distribution. Results based upon this information are not only affected by interstellar reddening but also are incapable of identifying common spectral peculiarities. The use of spectrophotometric indices (Beavers and Cook 1980) avoids the major difficulties of other techniques. The results are not influenced by the veiling or blending of lines, nor are the results influenced by interstellar reddening. If a sufficient number of features are observed, common types of spectral peculiarities can be identified.

Inhibition of osmotic thirst by electric stimulation of the basal forebrain in dogs

The effect of electrical brain stimulation (ESB; 50 Hz, 50-150 microA sine wave, 5 s on/5 s off) on osmotic thirst was examined in 10 conscious dogs chronically implanted with electrodes aimed at the anteromedial part of the basal forebrain. Suppression of osmotic thirst (SOT) was observed during stimulation through 18 of 41 electrodes located in the olfactory tubercle, the nucleus accumbens, the caudate nucleus, the medial septum, and the lateral preoptic-anterolateral hypothalamic area (PrA/ALH). Mean increment in plasma osmolality necessary to cause drinking rose from 9.0 +/- 1.5 mosmol (X +/- SE; n = 15) under control conditions to 15.8 +/- 2.6 mosmol (n = 18) during ESB in SOT placements. Threshold cellular dehydration eliciting drinking increased from 2.70 +/- 0.50% of intracellular water (ICW;n = 16) to 4.77 +/- 0.68% of ICW (n = 18), respectively. The strongest SOT was found during ESB in the nucleus accumbens, and the PrA/ALH. The same stimulation failed to inhibit feeding, support self-stimulation or produce appreciable changes of dog's gross behavior. The results give evidence for the existence in the basal forebrain of the dog a widely distributed neural system suppressing osmotic thirst. The nucleus accumbens and the PrA/ALH seem to play an important role in this system.