bluuebunny/crossref_metadata_2025_split huggingface dataset:
Individual differences in response to sibling birth among free-ranging yearling rhesus monkeys (Macaca mulatta) on Cayo Santiago
Authors: Rasmussen  , Berman  , Devinney  
Published: October 2003

AbstractThe birth of a younger sibling is a normal event in the life of a nonhuman primate, yet commonly it is thought to be a stressful transition for the older sibling. In our previous research, we found that yearling rhesus monkeys (Macaca mulatta) experienced increases in one mild form of distress but no significant increases in overt forms of distress, in spite of significant reductions in mother-yearling interaction. Nevertheless, some individual yearlings were distressed by this transition and here we examine variables that may structure individual differences in distress. We observed 31 yearling rhesus monkeys on Cayo Santiago, Puerto Rico, during the month before and month after their siblings' births using focal animal sampling methods. Attachment theory (Bowlby, 1969), parent-offspring conflict theory (Trivers, 1974), and dynamic assessment models (Bateson, 1994) all predict a relationship between reduction in maternal care and increase in offspring distress, yet no previous study of sibling birth in primates has examined this relationship. We found that the reduction in the proportion of time on the nipple from the month before sibling birth to the month after was related to the rate of geckering (a distress vocalization) after sibling birth, and that the increase in time out of sight of the mother was related to the proportion of time yearlings spent in a tense state after sibling birth. Maternal aggression after sibling birth also was related to the yearlings' rate of geckering. Yearling distress was related to qualities of the mother-yearling relationship, in that yearlings that had relatively greater responsibility for maintaining proximity with their mothers before sibling birth were relatively more tense afterwards. Yearlings displayed increases in play, grooming, and contact with group members other than the mother after sibling birth, suggesting a marked shift toward greater maturity in their social relationships.
Self-odour recognition in European storm-petrel chicks
Authors: Belliure Belén , Mínguez Eduardo , De León Ana 
Published: October 2003

AbstractIn common with many other species of Procellariform, the European storm-petrel (Hydrobates pelagicus) has a well-developed olfactory anatomy, and chicks are able to recognize their own nests by smell. However, it is not known which olfactory cues these birds use to locate their burrows. To find out if body scent is one of these olfactory cues we used a T-maze device to perform three different preference tests. Chicks were allowed to choose between their own odour plus their nest, and a neutral odour; between their own odour and a neutral odour (far from any nest); and finally between their own odour and the body scent of a conspecific chick. Storm-petrel chicks can apparently recognize their own body odour, even when tested against the body scent of a conspecific. Individually distinctive odours may play an important role in facilitating nest recognition. The results indicate self-odour recognition, and suggest that individual odour recognition could play an important role in social relationships of storm-petrels.
Increased per-capita investment in egg production by female apple snails in the presence of predatory common carp
Authors: Ichinose Katsuya , Tochihara Masahisa 
Published: October 2003

AbstractWe hypothesized that apple snails would change life-history traits in the presence of common carp to reduce or avoid predation risk. Carp of about 150 mm body length were released in small plots set in a rice field in southern Japan at 0, 0.2, or 0.6 carp/m2. Egg-mass size, proportion of hatched eggs, and duration of hatching of the snail were measured once or twice a week from July to September. Snails collected in traps were used to estimate both snail density by the Jolly-Seber mark-recapture method and distribution of shell lengths in each plot. The weight of the snail was regressed on a size-weight equation, and the snail biomass was determined by multiplying the estimated density and the regressed weight. The reproductive effort of the snails was calculated as the number of eggs divided by the biomass of adult females. The egg mass size and reproductive effort were significantly increased in the presence of carp. These increases were considered as life-history changes of apple snails in the presence of a predator.
Microgeographic song variation in island populations of the white-crowned sparrow (Zonotrichia leucophrys nutalli): innovation through recombination
Authors: Bell Douglas , Slabbekoorn Hans , Jesse Andrea 
Published: October 2003

AbstractCurrent geographic variation in bird song dialects may be used to infer historical processes involved in dialect formation. Discrete island populations, separated by water or unsuitable habitat, may be particularly useful as they allow for unequivocal subdivision of populations. We analyzed song recordings of nine populations of the white-crowned sparrow within the San Francisco Bay area, both on 'true' islands separated by water and in habitat islands along the Bay shore. We found one or two unique songtypes in each population with little variation within songtypes among individuals. Differences in songtypes concerned variation in syntax, syllable shapes, and spectral and temporal features. While each songtype exhibited unique features, there were often parts of the song that showed high similarity with songtypes of neighboring populations. We think that successfully dispersing males may learn from multiple tutors and produce songtype hybrids which could explain the variation in songtypes among populations. We found rare acoustic features on the 'true' islands, but also an apparent lack of impact by water barriers on the relationship between song similarity and geographic distance. A possible explanation may be that male dispersal, or just spread of song characteristics, is predominantly from island to mainland. Such a unidirectional pattern could result in rare song characteristics on islands, while general acoustic characteristics are still shared with the nearest mainland populations. Variation in similarity-based clustering of songtypes suggested that new songtypes emerge through recombination of components from existing songtypes.
Use of multiple orientation cues by juvenile loggerhead sea turtlesCaretta caretta
Authors: Avens Larisa , Lohmann Kenneth J. 
Published: October 2003

SUMMARYAlthough the orientation cues used by hatchling sea turtles have been studied extensively, little is known about the mechanisms of orientation and navigation that guide older turtles. To investigate the orientation cues used by juvenile loggerheads Caretta caretta L., captured turtles were tethered in a water-filled arena located outdoors. Turtles tested under these conditions established and maintained headings in specific directions in the absence of wave cues, familiar landmarks and chemical gradients. Distorting the magnetic field around the anterior part of a turtle's body did not disrupt orientation if vision remained unimpaired. Similarly, eliminating visual cues by attaching frosted goggles did not disrupt orientation if the magnetic environment was undisturbed. However, when turtles experienced a simultaneous disruption of magnetic and visual cues, their orientation was altered. These results imply that sea turtles, like migratory birds and homing pigeons, are able to maintain headings using multiple sources of directional information.
The aerodynamics of insect flight
Authors: Sane Sanjay P. 
Published: October 2003

SUMMARYThe flight of insects has fascinated physicists and biologists for more than a century. Yet, until recently, researchers were unable to rigorously quantify the complex wing motions of flapping insects or measure the forces and flows around their wings. However, recent developments in high-speed videography and tools for computational and mechanical modeling have allowed researchers to make rapid progress in advancing our understanding of insect flight. These mechanical and computational fluid dynamic models, combined with modern flow visualization techniques, have revealed that the fluid dynamic phenomena underlying flapping flight are different from those of non-flapping,2-D wings on which most previous models were based. In particular, even at high angles of attack, a prominent leading edge vortex remains stably attached on the insect wing and does not shed into an unsteady wake, as would be expected from non-flapping 2-D wings. Its presence greatly enhances the forces generated by the wing, thus enabling insects to hover or maneuver. In addition, flight forces are further enhanced by other mechanisms acting during changes in angle of attack, especially at stroke reversal, the mutual interaction of the two wings at dorsal stroke reversal or wing–wake interactions following stroke reversal. This progress has enabled the development of simple analytical and empirical models that allow us to calculate the instantaneous forces on flapping insect wings more accurately than was previously possible. It also promises to foster new and exciting multi-disciplinary collaborations between physicists who seek to explain the phenomenology, biologists who seek to understand its relevance to insect physiology and evolution, and engineers who are inspired to build micro-robotic insects using these principles. This review covers the basic physical principles underlying flapping flight in insects, results of recent experiments concerning the aerodynamics of insect flight, as well as the different approaches used to model these phenomena.
Introductory tail-flick of the Jacky dragon visual display: signal efficacy depends upon duration
Authors: Peters Richard A. , Evans Christopher S. 
Published: October 2003

SUMMARYMany animal signals have introductory components that alert receivers. Examples from the acoustic and visual domains show that this effect is often achieved with high intensity, a simple structure and a short duration. Quantitative analyses of the Jacky dragon Amphibolurus muricatusvisual display reveal a different design: the introductory tail-flick has a lower velocity than subsequent components of the signal, but a longer duration. Here, using a series of video playback experiments with a digitally animated tail, we identify the properties responsible for signal efficacy. We began by validating the use of the computer-generated tail, comparing the responses to digital video footage of a lizard tail-flick with those to a precisely matched 3-D animation (Experiment 1). We then examined the effects of variation in stimulus speed, acceleration, duration and period by expanding and compressing the time scale of the sequence (Experiment 2). The results identified several variables that might mediate recognition. Two follow-up studies assessed the importance of tail-flick amplitude (Experiment 3),movement speed and signal duration (Experiment 4). Lizard responses to this array of stimuli reveal that duration is the most important characteristic of the tail-flick, and that intermittent signalling has the same effect as continuous movement. We suggest that signal design may reflect a trade-off between efficacy and cost.
Catecholamine secretion in trout chromaffin cells experiencing nicotinic receptor desensitization is maintained by non-cholinergic neurotransmission
Authors: McNeill Brian , Montpetit Colin J. , Perry Steve F. 
Published: October 2003

SUMMARYThe goal of the present study was to assess the catecholamine secretory capabilities of rainbow trout Oncorhynchus mykiss chromaffin cells experiencing desensitization of the nicotinic receptor. It was hypothesized that the potential to secrete catecholamines could be maintained under conditions of nicotinic receptor desensitization owing to activation of non-cholinergic release pathways. An in situ model for chromaffin cell nicotinic receptor desensitization was developed by perfusing a posterior cardinal vein preparation with saline containing 10–5 mol l–1 nicotine. Under such conditions of desensitization, the chromaffin cells were largely unresponsive to high-frequency (20 Hz)electrical stimulation; the minimal remaining secretory response was abolished by addition of the nicotinic receptor antagonist hexamethonium(10–3 mol l–1). In marked contrast, however,the capacity to secrete catecholamines in response to low-frequency (1 Hz)electrical stimulation was unaffected by nicotinic receptor desensitization or by cholinergic receptor blockade (hexamethonium plus atropine). In preparations experiencing nicotinic receptor desensitization, the stimulatory effect of low-frequency (1 Hz) stimulation on catecholamine secretion was reduced by 43% in the presence of the VPAC receptor antagonist,VIP6-28. The stimulatory effect of high-frequency (20 Hz)stimulation was unaffected by VIP6-28. Catecholamine secretion evoked by cod VIP (10–11 mol kg–1) and homologous angiotensin II ([Asn1, Val5] Ang II;5×10–7 mol kg–1) was markedly enhanced(107 and 97%, respectively) in desensitized preparations. However, the secretory response to the muscarinic receptor agonist methylcholine(1×10–3 mol kg–1) was unchanged by desensitization. The results of this study demonstrate that exploitation of non-cholinergic mechanisms, including peptidergic pathways activated during low-frequency neuronal stimulation, is a potential strategy whereby catecholamine secretion from trout chromaffin cells can be maintained during periods of nicotinic receptor desensitization.
Limits to sustained energy intake VIII. Resting metabolic rate and organ morphology of laboratory mice lactating at thermoneutrality
Authors: Król E. , Johnson M. S. , Speakman J. R. 
Published: October 2003

SUMMARYWe have previously shown that the food intake and milk production of MF1 laboratory mice lactating at 30°C, 21°C and 8°C increase as temperature declines. These data suggest that mice are not limited peripherally by the capacity of the mammary glands to produce milk but are limited by the capacity of the animal to dissipate body heat generated as a by-product of food processing and milk production. Here, we measure resting metabolic rate (RMR; prior to breeding and at peak lactation) and organ morphology (at peak lactation) in MF1 mice exposed to 30°C(thermoneutrality) and compare these traits with the same parameters measured previously in mice at 21°C and 8°C. The masses of visceral organs primarily responsible for energy flux (heart, lungs, stomach, small intestine,large intestine, liver, pancreas, spleen and kidneys) increased as temperature declined. The masses of all these organs differed between mice exposed to 8°C and 21°C, whereas only the masses of heart, liver and kidneys differed between mice at 21°C and 30°C. The increases in organ masses were paralleled by increases in RMR at peak lactation above the levels measured prior to breeding, with mice at 8°C and 21°C having significantly higher increases in RMR than mice at 30°C (29.6 kJ day–1, 25.5 kJ day–1 and 8.1 kJ day–1, respectively). The observed changes in visceral organs and RMR are consistent with both the heat dissipation and peripheral limit hypotheses. However, mice exposed to 8°C had substantially larger mammary glands than mice at 21°C or 30°C (2.450 g, 1.115 g and 0.956 g dry mass, respectively), which argues against the peripheral limitation hypothesis and is consistent with the heat dissipation limit hypothesis. In addition, cold exposure resulted in greater masses of brown adipose tissue,white adipose tissue, pelage and tail. We discuss these changes in the context of the potential thermoregulatory benefits from use of the heat generated as a by-product of milk synthesis.
MysteriousMystacina: how the New Zealand short-tailed bat(Mystacina tuberculata) locates insect prey
Authors: Jones Gareth , Webb Peter I. , Sedgeley Jane A. , O'Donnell Colin F. J. 
Published: October 2003

SUMMARYThe New Zealand short-tailed bat Mystacina tuberculata evolved in the absence of terrestrial mammals and initially with few potential predators. Unusual among bats, it is well adapted for the capture of prey on the ground. Bats from Fiordland, New Zealand had relatively low wing loadings and aspect ratios adapted for flight in cluttered habitats. We predicted that M. tuberculata would locate prey in air (uncluttered space) by echolocation. Echolocation call sequences associated with prey capture (terminal buzzes)were heard in the field, and bats detected and localized prey suspended on fishing line by echolocation in a flight cage. The bats emitted brief,multiharmonic echolocation calls at low duty cycle during search phase, and 64% of calls contained most energy in the fundamental harmonic. Approach- and terminal-phase calls were also broadband and multiharmonic. We predicted that bats would not use echolocation to locate prey hidden on the ground in leaf litter (cluttered space). Bats seemed unable to locate hidden prey precisely from the air and instead hunted for such prey while crawling. Echolocation calls were emitted at a low repetition rate on the ground, suggesting that here echolocation was used for orientation and not for prey detection. We experimentally removed cues available to the bats and showed that bats located mealworms in leaf litter by listening for prey-generated noises and possibly by olfaction.
Hot bees in empty broodnest cells: heating from within
Authors: Kleinhenz Marco , Bujok Brigitte , Fuchs Stefan , Tautz Jürgen 
Published: October 2003

SUMMARYHoneybee colonies maintain brood nest temperatures of 33–36°C. We investigated brood nest thermoregulation at the level of individual worker behaviour and the transfer of heat from workers to the brood. Worker bees contribute to the regulation of brood nest temperature by producing heat while sitting motionless on the caps of brood cells. We report here an additional,newly observed heating strategy where heating bees enter empty cells between sealed brood cells and remain there motionless for periods of up to 45 min.Individually marked worker bees on the surface of sealed brood cells maintained thorax temperatures (Tth) between 32.2±1.0°C and 38.1±2.5°C (mean ± s.d.; N=20 bees) with alternating warming and cooling periods. Most of the observed bees made one or several long-duration visits(&gt;2 min) to empty cells within the sealed brood area. Tth at the time bees entered a cell[Tth(entry)] was 34.1–42.5°C (N=40). In 83% of these cell visits, Tth(entry) was higher (up to 5.9°C; mean 2.5±1.5°C; N=33) than the mean Tth of the same bee. High values of Tth(entry) resulted from preceding heating activity on the comb surface and from warm-ups just prior to cell visits during which Tth increased by up to +9.6°C.Bees inside empty cells had mean Tth values of 32.7±0.1°C (resting bees) to 40.6±0.7°C (heat-producing bees) during long-duration cell visits without performing any visible work. Heating behaviour inside cells resembles heating behaviour on the brood cap surface in that the bees appear to be inactive, but repeated warmings and coolings occur and Tth does not fall below the optimum brood temperature.Bees staying still inside empty cells for several minutes have previously been considered to be `resting bees'. We find, however, that the heating bees can be distinguished from the resting bees not only by their higher body temperatures but also by the continuous, rapid respiratory movements of their abdomens. By contrast, abdominal pumping movements in resting bees are discontinuous and interrupted by long pauses.Heat transfer to the brood from individual bees on the comb surface and from bees inside empty cells was simulated under controlled conditions. Heating on the comb surface causes a strong superficial warming of the brood cap by up to 3°C within 30 min. Heat transfer is 1.9–2.6 times more efficient when the thorax is in touch with the brood cap than when it is not. Heating inside empty cells raises the brood temperature of adjacent cells by up to 2.5°C within 30 min. Heat flow through the comb was detectable up to three brood cells away from the heated thorax.
Ventricular haemodynamics inPython molurus: separation of pulmonary and systemic pressures
Authors: Wang Tobias , Altimiras Jordi , Klein Wilfried , Axelsson Michael 
Published: October 2003

SUMMARYVascular pressure separation by virtue of a two-chambered ventricle evolved independently in mammals and birds from a reptilian ancestor with a single ventricle, and allowed for high systemic perfusion pressure while protecting the lungs from oedema. Within non-crocodilian reptiles, ventricular pressure separation has only been observed in varanid lizards and has been regarded as a unique adaptation to an active predatory life style and high metabolic rate. The systemic and pulmonary sides of the ventricle in Python molurusare well separated by the muscular ridge, and a previous study using in situ perfusion of the heart revealed a remarkable flow separation and showed that the systemic side can sustain higher output pressures than the pulmonary side. Here we extend these observations by showing that systemic blood pressure Psys exceeded pulmonary pressure Ppul almost seven times (75.7±4.2 versus11.6±1.1 cm H2O). The large pressure difference between the systemic and pulmonary circulation persisted when Psys was altered by infusion of sodium nitroprusside or phenylephrine. Intraventricular pressures, measured in anaesthetised snakes, showed an overlap in the pressure profile between the pulmonary side of the ventricle (cavum pulmonale) and the pulmonary artery, while the higher pressure in the systemic side of the ventricle (cavum arteriosum) overlapped with the pressure in the right aortic arch. This verifies that the pressure differences originate within the ventricle, indicating that the large muscular ridge separates the ventricle during cardiac contraction.
Aggregation through the Quadrupole Interactions of Gold(I) Complex with Triphenylphosphine and Pentafluorobenzenethiolate
Authors: Watase Seiji , Kitamura Takayuki , Kanehisa Nobuko , Shizuma Motohiro , Nakamoto Masami , Kai Yasushi , Yanagida Shozo 
Published: October 2003

Abstract
A new class of the aggregation of the gold(I) phosphine complex with pentafluorobenzenethiolate ligand through intermolecular quadrupole interactions was designed and characterized both by X-ray crystallography in solid state and by electrospray ionization mass spectroscopy in solution.
Liquid Phase Hydrogenation of Phenol to Cyclohexenone Over A Pd–La–B Amorphous Catalyst
Authors: Zhuang Li , Li Hexing , Dai Weilin , Qiao Minghua 
Published: October 2003

Abstract
A La-doped Pd–B amorphous catalyst (Pd–La–B) was prepared by chemical reduction of mixed PdCl2 and LaCl3 with KBH4. The La-dopant played a key role in stabilizing the amorphous structure since only the crystalline Pd–B was obtained without the La-dopant. During liquid phase phenol hydrogenation, the as-prepared Pd–La–B exhibited higher activity and better selectivity to cyclohexanone than the undoped Pd–B.
Trimethylsilylated Chitosan: A Convenient Precursor for Chemical Modifications
Authors: Kurita Keisuke , Hirakawa Masaaki , Aida Kaori , Yang Jin , Nishiyama Yasuhiro 
Published: October 2003

Abstract
Trimethylsilylation of chitosan was attained efficiently with hexamethyldisilazane and chlorotrimethylsilane. The resulting silylated derivative was characterized by remarkable reactivity as well as improved solubility and proved to be a convenient precursor for modification reactions.
UV Light-assisted Chemical Vapor Deposition of TiO2 for Efficiency Development at Dye-sensitized Mesoporous Layers on Plastic Film Electrodes
Authors: Murakami Takurou N , Kijitori Yujiro , Kawashima Norimichi , Miyasaka Tsutomu 
Published: October 2003

Abstract
Chemical vapor deposition of TiO2 combined with UV light irradiation at nanocrystalline TiO2 particle layers coated on plastic film electrodes (ITO-PET) drastically enhanced dye-sensitized photocurrent and improved photovoltage up to 750 mV, achieving energy conversion efficiency of 3.8%.