Male-infant-male interactions in Tibetan macaques

Event-sampling and scans were used for collecting data on male-infant-male triadic interactions, and their effects on member spacing respectively in a group of Macaca thibetana at Mt. Emei in 1989. The group was partially provisioned by human visitors in seasons other than winter, and could be observed closely. In addition, a stable linear male-hierarchy among five males existed for two years since the end of 1987, providing a good social condition for this topic. The triadic interactions were specific to the birth season, and recognized as three types being on a continuum functionally changing from passive ''agonistic buffering'' (4.8%) to active spatial cohesion, which resulted in a significant decline of intermale distances. Positive correlations were documented between the triad initiation rate and the number of females in consort with the males in the mating season (MS), and between the triad reception rate and the number of infants in proximity to the males in the MS when maternal care was significantly reduced. Thus the male's mating effort and kin/sexual selection may deeply be involved in the triad of this species. Considering that the two triad-species, M. sylvanus and M. thibetana, had different levels of paternity, but shared similar foraging conditions, and showed similar intensities of male-infant caretaking, the triad was very likely a byproduct of male-infant caretaking, which was probably shaped to compensate heavy maternal investment to young offspring in harsh conditions. Accordingly, the long-term arguments about the triad in M. sylvanus can be united to a model of the way in which ''male-infant caretaking'' hypothesis works ultimately, and ''regulating social relations'' hypothesis does proximately.

Intergroup interactions in Tibetan macaques at Mt. Emei, China

Data on intergroup-interactions (I-I) were collected in 5 seasonally provisioned groups (A, B, D, D-1, and E) of Tibetan macaques (Macaca Thibetana) at Mt. Emei in three 70-day periods between 1991 April-June (P1), September-November (P2), December-1992 February (P3). The I-I were categorized as forewarning made by high-ranking males (including Branch Shaking and/or Loud Calls), long-distance interactions in space (specified by changes in their foraging movements), and close encounters (with Affinitive Behavior, Male's Herding Female, Sexual Interaction, Severe Conflict, Adult Male-male Conflict, Opportunistic Advance and Retreat, etc. performed by different age-sex classes). From periods Fl to P3, the I-I rate decreased with reduction in population density as a positive correlate of food clumpedness or the number of potential feeders along a pedestrian trail. On the other hand, from the birth season (BS, represented by P1 and P3) to the mating season (MS, represented by P2) the dominance relation between groups, which produced a winner and a loser in the encounters, became obscure; the proportion of close encounters in the I-I increased; the asymmetry (local groups over intruders) of forewarning signals disappeared; the rate of branch shaking decreased; and sometimes intergroup cohesion appeared. Considering that sexual interactions also occurred between the encountering groups, above changes in intergroup behaviors may be explained with a model of the way in which the competition for food (exclusion) and the sexual attractiveness between opposite sexes were in a dynamic equilibrium among the groups, with the former outweighing the latter in the BS, and conversely in the MS. Females made 93% of severe conflicts, which occurred in 18% of close encounters. Groups fissioned in the recent past shared the same home range, and showed the highest hostility to each other by females. In conspicuous contrast with females' great interest in intergroup food/range competition, adult male-male conflicts that were normally without body contact occurred in 66% bf close encounters; high-ranking male herding of females, which is typical in baboons, appeared in 83% of close encounters, and showed no changes with season and sexual weight-dimorphism; peripheral juvenile and subadult males were the main performers of the affinitive behaviors, opportunistic advance and retreat, and guarding at the border. In brief, all males appeared to "sit on the fence" at the border, likely holding out hope of gaining the favor of females both within and outside the group. Thus, females and males attempted to maximize reproductive values in different ways, just as expected by Darwin-Trivers' theory of sexual selection. In addition, group fission was observed in the largest and highest-ranking group for two times (both in the MS) when its size increased to a certain level, and the mother group kept their dominant position in size and rank among the groups that might encounter, suggesting that fission takes a way of discarding the "superfluous part" in order to balance the cost of competition for food and mates within a group, and the benefit of cooperation to access the resources for animals in the mother group. (C) 1997 Wiley-Liss, Inc.

Assessment of computational fluid dynamics and experimental data for shock boundary-layer interactions

A workshop on the computational fluid dynamics (CFD) prediction of shock boundary-layer interactions (SBLIs) was held at the 48th AIAA Aerospace Sciences Meeting. As part of the workshop, numerous CFD analysts submitted solutions to four experimentally measured SBLIs. This paper describes the assessment of the CFD predictions. The assessment includes an uncertainty analysis of the experimental data, the definition of an error metric, and the application of that metric to the CFD solutions. The CFD solutions provided very similar levels of error and, in general, it was difficult to discern clear trends in the data. For the Reynolds-averaged Navier-Stokes (RANS) methods, the choice of turbulence model appeared to be the largest factor in solution accuracy. Scale-resolving methods, such as large-eddy simulation (LES), hybrid RANS/LES, and direct numerical simulation, produced error levels similar to RANS methods but provided superior predictions of normal stresses. Copyright © 2012 by Daniella E. Raveh and Michael Iovnovich.

Social sensing in the field: Challenges in detecting social interactions in construction sites

Construction industry is a sector that is renowned for the slow uptake of new technologies. This is usually due to the conservative nature of this sector that relies heavily on tried and tested and successful old business practices. However, there is an eagerness in this industry to adopt Building Information Modelling (BIM) technologies to capture and record accurate information about a building project. But vast amounts of information and knowledge about the construction process is typically hidden within informal social interactions that take place in the work environment. In this paper we present a vision where smartphones and tablet devices carried by construction workers are used to capture the interaction and communication between workers in the field. Informal chats about decisions taken in the field, impromptu formation of teams, identification of key persons for certain tasks, and tracking the flow of information across the project community, are some pieces of information that could be captured by employing social sensing in the field. This information can not only be used during the construction to improve the site processes but it can also be exploited by the end user during maintenance of the building. We highlight the challenges that need to be overcome for this mobile and social sensing system to become a reality. © 2012 ACM.

Corner separation effects for normal shock wave/turbulent boundary layer interactions in rectangular channels

Experiments are conducted to examine the mechanisms behind the coupling between corner separation and separation away from the corner when holding a high-Machnumber M∞ = 1.5 normal shock in a rectangular channel. The ensuing shock wave interaction with the boundary layer on the wind tunnel floor and in the corners was studied using laser Doppler anemometry, Pitot probe traverses, pressure sensitive paint and flow visualization. The primary mechanism explaining the link between the corner separation size and the other areas of separation appears to be the generation of compression waves at the corner, which act to smear the adverse pressure gradient imposed upon other parts of the flow. Experimental results indicate that the alteration of the -region, which occurs in the supersonic portion of the shock wave/boundary layer interaction (SBLI), is more important than the generation of any blockage in the subsonic region downstream of the shock wave. © Copyright 2012 Cambridge University Press.

Flame interactions in turbulent premixed twin V-flames

Multiple flame-flame interactions in premixed combustion are investigated using direct numerical simulations of twin turbulent V-flames for a range of turbulence intensities and length scales. Interactions are identified using a novel automatic feature extraction (AFE) technique, based on data registration using the dual-tree complex wavelet transform. Information on the time, position, and type of interactions, and their influence on the flame area is extracted using AFE. Characteristic length and time scales for the interactions are identified. The effect of interactions on the flame brush is quantified through a global stretch rate, defined as the sum of flamelet stretch and interaction stretch contributions. The effects of each interaction type are discussed. It is found that the magnitude of the fluctuations in flamelet and interaction stretch are comparable, and a qualitative sensitivity to turbulence length scale is found for one interaction type. Implications for modeling are discussed. © 2013 Copyright Taylor and Francis Group, LLC.

The effect of contextual cues on the encoding of motor memories.

Several studies have shown that sensory contextual cues can reduce the interference observed during learning of opposing force fields. However, because each study examined a small set of cues, often in a unique paradigm, the relative efficacy of different sensory contextual cues is unclear. In the present study we quantify how seven contextual cues, some investigated previously and some novel, affect the formation and recall of motor memories. Subjects made movements in a velocity-dependent curl field, with direction varying randomly from trial to trial but always associated with a unique contextual cue. Linking field direction to the cursor or background color, or to peripheral visual motion cues, did not reduce interference. In contrast, the orientation of a visual object attached to the hand cursor significantly reduced interference, albeit by a small amount. When the fields were associated with movement in different locations in the workspace, a substantial reduction in interference was observed. We tested whether this reduction in interference was due to the different locations of the visual feedback (targets and cursor) or the movements (proprioceptive). When the fields were associated only with changes in visual display location (movements always made centrally) or only with changes in the movement location (visual feedback always displayed centrally), a substantial reduction in interference was observed. These results show that although some visual cues can lead to the formation and recall of distinct representations in motor memory, changes in spatial visual and proprioceptive states of the movement are far more effective than changes in simple visual contextual cues.

Normal shock interactions in rectangular channels

Experiments have been conducted to examine the mechanisms behind the coupling between corner separation and centreline separation when holding a normal shock in a rectangular channel. The study has focused on a M ∞ = 1.5 normal shock held in a wind tunnel with a parallel rectangular cross-section. The primary mechanism explaining the link between the corner separation size and the centreline separation appears to be the generation of compression waves which act to smear the adverse pressure gradient imposed upon other parts of the flow. In addition, the origin of the λ-foot leading leg appears to be depended upon the size of the corner separations. Experimental results indicate that the alteration of the λ-region, which occurs in the supersonic portion of the SBLI, is more important than the generation of any blockage in the subsonic region downstream of the shock wave. Copyright © 2012 by H. Babinsky, D.M.F. Burton.

A genetically mediated bias in decision making driven by failure of amygdala control.

Genetic variation at the serotonin transporter-linked polymorphic region (5-HTTLPR) is associated with altered amygdala reactivity and lack of prefrontal regulatory control. Similar regions mediate decision-making biases driven by contextual cues and ambiguity, for example the "framing effect." We hypothesized that individuals hemozygous for the short (s) allele at the 5-HTTLPR would be more susceptible to framing. Participants, selected as homozygous for either the long (la) or s allele, performed a decision-making task where they made choices between receiving an amount of money for certain and taking a gamble. A strong bias was evident toward choosing the certain option when the option was phrased in terms of gains and toward gambling when the decision was phrased in terms of losses (the frame effect). Critically, this bias was significantly greater in the ss group compared with the lala group. In simultaneously acquired functional magnetic resonance imaging data, the ss group showed greater amygdala during choices made in accord, compared with those made counter to the frame, an effect not seen in the lala group. These differences were also mirrored by differences in anterior cingulate-amygdala coupling between the genotype groups during decision making. Specifically, lala participants showed increased coupling during choices made counter to, relative to those made in accord with, the frame, with no such effect evident in ss participants. These data suggest that genetically mediated differences in prefrontal-amygdala interactions underpin interindividual differences in economic decision making.