Spontaneous whole body rotations and classical dance expertise: How shoulder–hip coordination influences supporting leg displacements

The link between supporting leg stability and individual trunk strategies used during spontaneous whole-body rotations was studied according to visual and kinesthetic imagery styles for classical dancers and untrained female participants. Shoulders–hip angles in the horizontal plane and supporting leg (SL) displacements were analyzed with three-dimensional kinematic at the beginning and end of the four turns, identified according to their SL (left vs. right) and turn direction (clockwise, CW vs. counterclockwise, CCW). To begin a turn in CCW on left SL, all the participants turned shoulders before hips (?25° angle), p < 0.01. Untrained participants yielded the reverse (+30° angle) in CW – their non-preferred turn - whereas dancers maintained their trunk en bloc. In the turn slow down, in their preferred direction all the participants adopted en bloc behavior to avoid imbalance. Dancers kept this pattern in CCW but untrained participants separated shoulders and hips, p < 0.01; on left SL (+20° angle) hips finished before shoulders and on right SL (?25° angle), shoulders finished before hips. Both mental imagery styles and spatial context link reduction of shoulder–hip angle and stability of SL. Daily expertise, not only dance training, facilitates the en bloc shoulder–hip coordination to maintain equilibrium.     

An intra-species demonstration of the independence of distance and time in turn alternation of the terrestrial isopod, Porcellio scaber

In a study of turn alternation in the terrestrial isopod Porcellio scaber (woodlouse), smaller individuals (<11 mm long) took significantly longer to traverse a 60-mm open-ended post-forced-turn runway following a 90 degrees forced turn, than larger subjects (>11 mm long). However, there were no significant differences between the two groups in their probability of alternating, or in the magnitude of alternating turns as reflected in the size of the free-turn angles they turned on emerging from the runway. Nor was there a significant relationship for either group between the time taken to traverse the runway and either the probability of alternating or the size of a free-turn angle. In a second experiment, significant alternation occurred after woodlice emerged from runways that were 30 and 60 mm long, but not when they were 100 or 145 mm long. Their free-turn angles also became smaller as the runway length increased. Overall, the results of the three experiments supported the long-held view that, for reasons not yet understood, distance and time cannot necessarily be equated in the determination of invertebrate turn alternation.     

Social recognition and approach in the chick: lateralization and effect of visual experience

Chicks, Gallus gallus domesticus, tested monocularly on day 3 after hatching recognize familiar versus unfamiliar conspecifics and choose to approach one or other when they use the left eye, whereas they approach familiar and unfamiliar chicks at random when they use the right eye. In experiment 1 we investigated the effects of light exposure of embryos prior to hatching on this particular form of lateralization. Irrespective of whether they hatched from eggs incubated in the dark or from eggs exposed to light during the final days of incubation, chicks using the left eye had higher choice scores (meaning they chose to approach either a familiar or an unfamiliar chick) than chicks using the right eye or both eyes. Therefore, light experience prior to hatching did not influence the lateralization of individual recognition or choice behaviour, although it did affect latency to move out of, and time spent in, the centre of the runway. Experiment 2 showed that visual/social experience posthatching influences choice behaviour: chicks housed in a group in the light for 12 h on day 1 posthatching made a clear choice between familiar and unfamiliar chicks when tested on day 3, but chicks kept in a group in the dark on day 1 did not make a choice, instead alternating between the two stimuli. In experiment 3 we found that posthatching visual/social experience increased the choice scores of chicks using the right eye and thereby removed any lateralization of choice behaviour. The results suggest that visual experience of a social group is required before chicks using their right eye (and left hemisphere) will pay attention to the cues that distinguish one chick from another. Chicks using their left eye (and right hemisphere) recognize the difference between individuals without requiring visual experience with other chicks. Copyright 2002 The Association for the Study of Animal Behaviour. Published by Elsevier Science Ltd. All rights reserved.     

Evidence of population-level lateralized behaviour in giant water bugs, Belostoma flumineum Say (Heteroptera: Belostomatidae): T-maze turning is left biased

Lateralized behaviour occurs in diverse animals, but relatively few studies examine the phenomenon in invertebrates. Here we report a population-level left turn bias in the giant water bug Belostoma flumineum Say (Heteroptera: Belostomatidae) in an underwater T-maze. Individuals made significantly more left turns than right turns, including when they were naïve and first introduced to the maze. Water bugs also showed significantly longer runs of consecutive left turns than right turns (i.e. LLLLL). The length of these runs, however, did not increase with experience in the maze, suggesting that the effect is not the result of learning. There were also no differences in turning bias between male and female water bugs. The proximate mechanism(s) underlying the left turn bias is unknown, but directional cues in the environment were eliminated by rotating the maze 180° between experiments, suggesting the mechanism(s) is endogenous. To our knowledge this is the first study of lateralized behaviour in the Heteroptera or in a swimming invertebrate animal.     

Digital fluoroscopic video assessment of glenohumeral migration: Static vs. Dynamic conditions

The purpose was to compare glenohumeral (GH) migration, during dynamic shoulder elevation and statically held positions using digital fluoroscopic videos (DFV). Thirty male volunteers (25±4 years) without right shoulder pathology were analyzed using DFV (30 Hz) during arm elevation in the scapular plane. DFV were obtained at the arm at side position, 45°, 90°, and 135° for static and dynamic conditions. GH migration was measured as the distance from the center of the humeral head migrated superiorly or inferiorly relative to the center of the glenoid fossa. Inter-rater reliability was considered good; ICC (2,3) ranged from 0.83 to 0.92. A main effect was revealed for contraction type (p=0.031), in which post-hoc t-tests revealed that humeral head was significantly more superior on the glenoid fossa during dynamic contraction. A main effect was also revealed for arm angle (p<0.001), in which post-hoc t-tests revealed significantly more superior humeral head positioning at 45°, 90°, and 135° when compared to arm at side (p<0.001), as well as at 90° compared to 45° (p=0.024). There was no interaction effect between angle and contraction type (p=0.400). Research utilizing static imaging may underestimate the amount of superior GH migration that occurs dynamically.     

Decrease in required coefficient of friction due to smaller lean angle during turning in older adults

We investigated age-related differences in the required coefficient of friction (RCOF) during 90° turning, the difference of RCOF during step and spin turn, and how affects observed differences. Sixteen healthy young and healthy older adults (eight men and eight women in each group) participated. Participants performed 90° step and spin turns to the right at a self-selected normal speed. Older adults turned with lower RCOF than the young adults during both step and spin turns. This was associated with reduced mediolateral (ML) RCOF component (RCOF_ML) for the older adults. Reduced RCOF_ML in older adults was associated with reductions in the ML component of the lean angle of the body during turning. This age-related gait changes during turning can be compensatory mechanisms that allowed older adults to turn while reducing the risk of slipping. Spin turns exhibited lower RCOF, resulting from significantly lower RCOF_ML, than step turns in young and older adults; thus, spin turning is a safer turning strategy for preventing lateral slips. This may suggest that, in older adults, slip prevention may take precedence over balance recovery after slips sustained during turning. These results illustrate a turning gait mechanism that helps prevent slips and falls, and how age affects this mechanism.     

Consensus movements by groups of sperm whales

When animals live in cohesive groups they need to make consensus decisions about movements. As a very large‐scale example of communal movement, nomadic female sperm whales (Physeter macrocephalus) travel about 50 km per day as coherent groups of 10–50 animals spread over several km of ocean. From 543 h of data during which 3,873 headings of small clusters of whales or individual whales were recorded, I quantified the heading behavior of groups foraging off the Galápagos Islands. The groups made both sudden and gradual turns. Using piecewise regression models, I estimate that sudden and gradual turns in heading both occurred at rates of 0.10/h. The mean change in heading was 69° for sudden turns and 84° for gradual turns. The mean duration of gradual turns was 1.3 h, so turns were often slow. Using the recorded headings within 30 min of each of 1,798 focal headings, a regression of heading on time gave a mean rate of turn of the group and error of each focal heading about the mean heading. Absolute heading errors increased with absolute turn rate (r_S = 0.241; P = 0.0000), so turns were often messy. Thus sperm whales often make slow and messy—likely democratic—consensus decisions when groups change heading.     

Effects of turn angle and pivot foot on lower extremity kinetics during walk and turn actions

This study examined lower extremity joint moments during walk and turn with different turn angles and pivot feet. Seven young adults (age 21+/-1.3 yrs) were asked to walk at a self-selected speed (1.35+/-0.15 m/s) and to turn to the right using right (spin turn) and left (step turn) pivot feet at turn angles of 0 degrees (walking straight), 45 degrees, and 90 degrees. Video and forceplate systems were employed for kinematic and kinetic data collection. Inverse dynamics approach was used to compute joint moments using segmental kinematics, ground reaction forces, and moments. The participants decreased their forward speed by increasing the ankle plantar flexion moment as the turn angle increased. The peak ankle plantar flexion moment during the braking phase increased with increasing turn angle for both spin and step turns. Ankle invertor moments were observed only in spin turns, suggesting that more ankle muscles are involved in spin turns than in step turns. The turn angle had a significant effect on the transverse plane moment profiles at the different lower extremity joints. The results suggest that the loading patterns of different anatomical structures in the lower extremity are affected by both turn angle and pivot foot during walk and turn actions.     

Critical parameters of the spike trains in a cell assembly: coding of turn direction by the giant interneurons of the cockroach

Cockroaches (Periplaneta americana) respond to air displacement produced by an approaching predator by turning and running away. A set of 4 bilateral pairs of ventral giant interneurons is important in determining turn direction. Wind from a given side is known to produce more spikes, an earlier onset of the spike trains, and different fine temporal patterning, in the ipsilateral vs the contralateral set of these interneurons. Here we investigate which of these spike train parameters the cockroach actually uses to determine the direction it will turn.We delivered controlled wind puffs from the right front, together with intracellular injection of spike trains in a left ventral giant interneuron, under conditions where the animal could make normally directed turning movements of the legs and body. In trials where our stimuli caused the left side to give both the first spike and more total spikes than the right, but where our injected spike train included none of the normal fine temporal patterning, 92% of the evoked turns were to the rightopposite of normal (Figs. 4–6). In trials where the left side gave the first spike, but the right side gave more spikes, 100% of the turns were to the left-the normal direction (Figs. 8, 9). Comparable results were obtained when each of the left giant interneurons 1, 2 or 3 were electrically stimulated, and when either weak or stronger wind puffs were used. Stimulating a left giant interneuron electrically in the absence of a wind puff evoked an escape-like turn on 9% of the trials, and these were all to the right (Fig. 9).These results indicate that fine temporal patterning in the spike trains is not necessary, and information about which side gives the first spike is not sufficient, to determine turn direction. Rather, the key parameter appears to be relative numbers of action potentials in the left vs the right group of cells. These conclusions were supported by similar experiments in which extracellular stimulation of several left giant interneurons was paired with right wind (Figs. 11, 12).Abbreviations GI giant interneuron - vGI ventral giant interneuron - dGI dorsal giant interneuron - LY Lucifer yellow - CF carboxyfluorescein     

Molecular cloning, characterization, and expression analysis of a cytosolic HSP90 gene from Haematococcus pluvialis

Heat shock protein 90 (HSP90) is a highly conserved molecular chaperone that plays key roles in the folding, maintenance of structural integrity, and regulation of a subset of cytosolic proteins. In this study, the cDNA of Haematococcus pluvialis HSP90 (designated HpHSP90) was cloned by the combination of homology cloning and rapid amplification of cDNA ends approaches. The full-length cDNA of HpHSP90 was of 2,606 bp, including an open reading frame of 2,109 bp encoding a polypeptide of 702 amino acids with predicted molecular weight of 80.14 kDa and theoretical isoelectric point of 5.07. BLAST analysis revealed that HpHSP90 shared high similarity with other known HSP90s, and the five conserved amino acid blocks defined as HSP90 protein family signatures were also identified in HpHSP90, which indicated that HpHSP90 should be a cytosolic member of the HSP90 family. Under different stress conditions, messenger RNA (mRNA) expression levels of HpHSP90 were quantified by quantitative RT-PCR. To H. pluvialis kept at different temperatures for 1 h, maximum HpHSP90 expression was observed in the range 5 to 10°C and 35 to 40°C and the expression level of HpHSP90 at 40°C was the highest (threefold compared with that at 25°C). In H. pluvialis kept at 35°C for different times, the mRNA expression level of HpHSP90 reached a maximum level after 7 h and then dropped progressively. The results indicate that HpHSP90 responded to cold and heat stresses with a temperature-dependent expression pattern as well as exposure time effect and could be used as a molecular biomarker in adverse stress environment.     

Mathematical biology of learning to drive an automobile

In learning to drive, an individual must learn to rapidly make small corrective turns to the right or to the left as the car comes too close correspondingly to the left or to the right edges of the lane. The magnitude of the corrective turn depends on the angle at which the edge is approached. Thus, the individual must learn to produce a quantitatively correct response (corrective turn) to any one of an infinite number of possible stimuli (angles of approach). By making a number of highly oversimplifying assumptions, the problem can be reduced to a learning situation, studied previously by H. D. Landahl (Bull. Math. Biophysic,3, 13–26, 71–77, 1941). This is used not so much to obtain any relation that might be considered practically applicable immediately as toillustrate what kind of relation can be obtained from such considerations. It is shown how the safe speed of a driver depends on his total driving experience (total distance driven) as well as on his psychophysical parameters.     

The influence of reward sequence on flight directionality in bees

Honeybees (Apis mellifera L.) were trained to collect food from arrays of artificial flowers. Experiments were carried out to investigate how different sequences of rewards (sugar solution) affect the flight directionality in the next inter-flower move (i.e. the tendency to keep to the same direction as in the preceding flight). In the texts, bees could visit a row of four or five flowers. At the end of the row, bees were given a choice of direction for their next flight (i.e. forward, left, right, or backward). I investigated the effect of a reward sequence in relation to (1) the average amount of ‘nectar’ gathered in the last few flower visits, regardless of the sequence of occurrence, or to (2) the reward received in the most recent flower visits. A reward given at the choice point itself reduced flight directionality. Effects of rewards offered on preceding flowers, i.e. one, two, or three steps before the choice point, were not significant. There was, however, evidence for their additional effect. It is concluded that the influence of a reward on flight directionality vanishes rapidly as more flower visits are made.     

Disorder and order in unfolded and disordered peptides and proteins: A view derived from tripeptide conformational analysis. II. Tripeptides with short side chains populating asx and β‐type like turn conformations

In the preceding paper, we found that ensembles of tripeptides with long or bulky chains can include up to 20% of various turns. Here, we determine the structural and thermodynamic characteristics of GxG peptides with short polar and/or ionizable central residues (D, N, C), whose conformational distributions exhibit higher than average percentage (>20%) of turn conformations. To probe the side‐chain conformations of these peptides, we determined the ³J(H^α,H^β) coupling constants and derived the population of three rotamers with χ₁‐angles of ?60°, 180° and 60°, which were correlated with residue propensities by DFT‐calculations. For protonated GDG, the rotamer distribution provides additional evidence for asx‐turns. A comparison of vibrational spectra and NMR coupling constants of protonated GDG, ionized GDG, and the protonated aspartic acid dipeptide revealed that side chain protonation increases the pPII content at the expense of turn populations. The charged terminal groups, however, have negligible influence on the conformational properties of the central residue. Like protonated GDG, cationic GCG samples asx‐turns to a significant extent. The temperature dependence of the UVCD spectra and ³J(H^NH^α) constants suggest that the turn populations of GDG and GNG are practically temperature‐independent, indicating enthalpic and entropic stabilization. The temperature‐independent J‐coupling and UVCD spectra of GNG require a three‐state model. Our results indicate that short side chains with hydrogen bonding capability in GxG segments of proteins may serve as hinge regions for establishing compact structures of unfolded proteins and peptides. Proteins 2013. © 2012 Wiley Periodicals, Inc.     

Effect of temperature and light on the photosynthesis as measured by chlorophyll fluorescence of cultured Eucheuma denticulatum and Kappaphycus sp. (Sumba strain) from Indonesia

The photosynthetic performance of two Indonesian carrageenophytes (Solieriaceae), Eucheuma denticulatum and Kappaphycus sp. (so-called Sumba strain), was investigated under a variety of temperature and light conditions regarding their mariculture performance. A pulse amplitude modulated-chlorophyll fluorometer (Diving-PAM) was used to generate rapid light curves (RLCs) to provide estimates of the relative electron transport rates (rETR) for over 10 temperatures (i.e., from 16 to 34 °C) and at nine levels of photosynthetic active radiation, which ranged from 0 to 1,000?μmol photons m^?2 s^?1. Underwater irradiance in a cultivation area was also measured at the collection site in South Sulawesi, Indonesia. The initial slope (α), photoinhibition coefficient (β), and the coefficient of maximum photosynthesis assuming no photoinhibition (γ) was calculated by fitting the RLCs to a nonlinear model of the form $ {\text{rETR}} = \gamma \left( {1 - \exp \left( { - \frac{\alpha }{\gamma }{\text{PAR}}} \right)} \right)\left( {\exp \left( { - \frac{\beta }{\gamma }{\text{PAR}}} \right)} \right) $ using a two-level hierarchical Bayesian model. The experiments revealed that E. denticulatum and Kappaphycus sp. required temperatures ranging from 23 to 32 °C and 22 to 33 °C to maintain high rates of photosynthetic activity, respectively. Clearly, both species appear to be well-adapted to the natural light and temperature conditions at the cultivation site, and we expect the results of this study will be useful for the design and sustainable management of similar mariculture activity.     

Effect of Trail Bifurcation Asymmetry and Pheromone Presence or Absence on Trail Choice by Lasius niger Ants

During foraging, ant workers are known to make use of multiple information sources, such as private information (personal memory) and social information (trail pheromones). Environmental effects on foraging, and how these interact with other information sources, have, however, been little studied. One environmental effect is trail bifurcation asymmetry. Ants forage on branching trail networks and must often decide which branch to take at a junction (bifurcation). This is an important decision, as finding food sources relies on making the correct choices at bifurcations. Bifurcation angle may provide important information when making this choice. We used a Y‐maze with a pivoting 90° bifurcation to study trail choice of Lasius niger foragers at varying branch asymmetries (0°, [both branches 45° from straight ahead], 30° [branches at 30° and 60° from straight ahead], 45°, 60° and 90° [one branch straight ahead, the other at 90°]). The experiment was carried out either with equal amounts of trail pheromone on both branches of the bifurcation or with pheromone present on only one branch. Our results show that with equal pheromone, trail asymmetry has a significant effect on trail choice. Ants preferentially follow the branch deviating least from straight, and this effect increases as asymmetry increases (47% at 0°, 54% at 30°, 57% at 45°, 66% at 60° and 73% at 90°). However, when pheromone is only present on one branch, the graded effect of asymmetry disappears. Overall, however, there is an effect of asymmetry as the preference of ants for the pheromone‐marked branch over the unmarked branch is reduced from 65%, when it is the less deviating branch, to 53%, when it is the more deviating branch. These results demonstrate that trail asymmetry influences ant decision‐making at bifurcations and that this information interacts with trail pheromone presence in a non‐hierarchical manner.     

Characterization of culturable Paenibacillus spp. from the snow surface on the high Antarctic Plateau (DOME C) and their dissemination in the Concordia research station

Culturable psychrotolerant bacteria were isolated from the top snow on the high Antarctic Plateau surrounding the research station Concordia. A total of 80 isolates were recovered, by enrichment cultures, from two different isolation sites (a distant pristine site [75° S 123° E] and a site near the secondary runway of Concordia). All isolates were classified to the genus Paenibacillus by 16S rRNA gene phylogenetic analysis and belonged to two different species (based on threshold of 97 % similarity in 16S rRNA gene sequence). ERIC-PCR fingerprinting indicated that the isolates from the two different sites were not all clonal. All isolates grew well from 4 to 37 °C and were resistant to ampicillin and streptomycin. In addition, the isolates from the secondary runway were resistant to chromate and sensitive to chloramphenicol, contrary to those from the pristine site. The isolates were compared to 29 Paenibacillus isolates, which were previously recovered from inside the Concordia research station. One of these inside isolates showed ERIC- and REP-PCR fingerprinting profiles identical to those of the runway isolates and was the only inside isolate that was resistant to chromate and sensitive to chloramphenicol. The latter suggested that dissemination of culturable Paenibacillus strains between the harsh Antarctic environment and the inside of the Concordia research station occurred. In addition, inducible prophages, which are potentially involved in horizontal dissemination of genes, were detected in Paenibacillus isolates recovered from outside and inside the station. The highest lysogeny was observed in strains harvested from the hostile environment outside the station.     

Behaviorally mediated,warm adaptation: A physiological strategy when mice behaviorally thermoregulate

Laboratory mice housed under standard vivarium conditions with an ambient temperature (T_a) of ~22 °C are likely to be cold stressed because this T_a is below their thermoneutral zone (TNZ). Mice raised at T_as within the TNZ adapt to the warmer temperatures, developing smaller internal organs and longer tails compared to mice raised at 22 °C. Since mice prefer T_as equal to their TNZ when housed in a thermocline, we hypothesized that mice reared for long periods (e.g., months) in a thermocline would undergo significant changes in organ development and tail length as a result of their thermoregulatory behavior. Groups of three female BALB/c mice at an age of 37 days were housed together in a thermocline consisting of a 90 cm long aluminum runway with a floor temperature ranging from 23 to 39 °C. Two side-by-side thermoclines allowed for a total of 6 mice to be tested simultaneously. Control mice were tested in isothermal runways maintained at a T_a of 22 °C. All groups were given cotton pads for bedding/nest building. Mass of heart, lung, liver, kidney, brain, and tail length were assessed after 73 days of treatment. Mice in the thermocline and control (isothermal) runways were compared to cage control mice housed 3/cage with bedding under standard vivarium conditions. Mice in the thermocline generally remained in the warm end throughout the daytime with little evidence of nest building, suggesting a state of thermal comfort. Mice in the isothermal runway built elaborate nests and huddled together in the daytime. Mice housed in the thermocline had significantly smaller livers and kidneys and an increase in tail length compared to mice in the isothermal runway as well as when compared to the cage controls. These patterns of organ growth and tail length of mice in the thermocline are akin to warm adaptation. Thus, thermoregulatory behavior altered organ development, a process we term behaviorally mediated, warm adaptation. Moreover, the data suggest that the standard vivarium conditions are likely a cold stress that alters normal organ development relative to mice allowed to select their thermal preferendum.     

Deceptive Body Movements Reverse Spatial Cueing in Soccer

The purpose of the experiments was to analyse the spatial cueing effects of the movements of soccer players executing normal and deceptive (step-over) turns with the ball. Stimuli comprised normal resolution or point-light video clips of soccer players dribbling a football towards the observer then turning right or left with the ball. Clips were curtailed before or on the turn (−160, −80, 0 or +80 ms) to examine the time course of direction prediction and spatial cueing effects. Participants were divided into higher-skilled (HS) and lower-skilled (LS) groups according to soccer experience. In experiment 1, accuracy on full video clips was higher than on point-light but results followed the same overall pattern. Both HS and LS groups correctly identified direction on normal moves at all occlusion levels. For deceptive moves, LS participants were significantly worse than chance and HS participants were somewhat more accurate but nevertheless substantially impaired. In experiment 2, point-light clips were used to cue a lateral target. HS and LS groups showed faster reaction times to targets that were congruent with the direction of normal turns, and to targets incongruent with the direction of deceptive turns. The reversed cueing by deceptive moves coincided with earlier kinematic events than cueing by normal moves. It is concluded that the body kinematics of soccer players generate spatial cueing effects when viewed from an opponent''s perspective. This could create a reaction time advantage when anticipating the direction of a normal move. A deceptive move is designed to turn this cueing advantage into a disadvantage. Acting on the basis of advance information, the presence of deceptive moves primes responses in the wrong direction, which may be only partly mitigated by delaying a response until veridical cues emerge.