bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modulation of flight muscle power output in budgerigarsMelopsittacus undulatusand zebra finchesTaeniopygia guttata:in vitromuscle performance
Authors: Ellerby David J. , Askew Graham N. 
Published: October 2007

SUMMARYThe pectoralis muscles are the main source of mechanical power for avian flight. The power output of these muscles must be modulated to meet the changing power requirements of flight across a range of speeds. This can be achieved at the muscle level by manipulation of strain trajectory and recruitment patterns, and/or by intermittent flight strategies. We have measured the in vitro power outputs of pectoralis muscle fascicles from budgerigars Melopsittacus undulatus and zebra finches Taeniopygia guttata under conditions replicating those previously measured in vivo during flight. This has allowed us to quantify the extent to which different power modulation mechanisms control flight muscle power output. Intermittent flight behaviour is a more important determinant of flight power in zebra finches than budgerigars. This behaviour accounts for 25–62% of power modulation relative to the maximum available mechanical power output in zebra finch, compared to 0–38% in budgerigars. Muscle level changes in fascicle strain trajectory and motor unit recruitment, rather than intermittent flight behaviours, are the main determinants of pectoralis muscle power output in budgerigars at all speeds, and in zebra finch at speeds below 14 m s–1.
Modulation of pectoralis muscle function in budgerigarsMelopsitaccus undulatusand zebra finchesTaeniopygia guttatain response to changing flight speed
Authors: Ellerby David J. , Askew Graham N. 
Published: October 2007

SUMMARYFlight power varies in a U-shaped relationship with flight speed, requiring the modulation of flight muscle power in order to meet these changing power demands. The power output of the pectoralis muscle can potentially be modulated by changing strain trajectory and the relative timing and intensity of muscle activity. Pectoralis muscle length change and activity patterns were recorded in budgerigars Melopsitaccus undulatus and zebra finches Taeniopygia guttata at a range of flight speeds using sonomicrometry and electromyography (EMG). The pectoralis muscles in these species contain a single muscle fibre type. Therefore, the power output is entirely determined by muscle activity and strain trajectory, rather than recruitment of motor units with different contractile properties as in many other vertebrate muscle systems. Relative EMG intensity, wingbeat frequency and muscle strain varied in an approximately U-shaped relationship with flight speed. The shape of the length trajectory varied with flight speed in budgerigars, with the proportion of the cycle spent shortening being lowest at intermediate flight speeds. In zebra finch pectoralis muscle the shape of the length trajectory did not vary significantly with flight speed. In both species the observed changes in muscle recruitment and length trajectory are consistent with meeting flight power requirements that vary in a U-shaped pattern with speed. Both species utilised intermittent flight, tending to spend relatively less time flapping at intermediate flight speeds. This supports the idea that intermittent flight is used as a simple power modulation strategy. However, the idea that intermittent flight serves to maintain a `fixed gear' is over-simplistic and fails to recognise the plasticity in performance at the level of the muscle. Intermittent flight is only one component of a complex power modulation strategy.
Immunohistochemical characterization of a parapinopsin-containing photoreceptor cell involved in the ultraviolet/green discrimination in the pineal organ of the river lamprey Lethenteron japonicum
Authors: Kawano-Yamashita Emi , Terakita Akihisa , Koyanagi Mitsumasa , Shichida Yoshinori , Oishi Tadashi , Tamotsu Satoshi 
Published: October 2007

SUMMARY
In the pineal organ, two types of ganglion cell exhibit antagonistic chromatic responses to UV and green light, and achromatic responses to visible light. In this study, we histologically characterized UV-sensitive photoreceptor cells that contain a unique non-visual UV pigment, lamprey parapinopsin, in order to elucidate the neural network that is associated with antagonistic chromatic responses. These characteristics were compared with those of lamprey rhodopsin-containing cells, most of which are involved in achromatic responses. RT-PCR analysis revealed that lamprey parapinopsin was expressed in the pineal organ but not in the retina, unlike lamprey rhodopsin,which was expressed in both. Lamprey parapinopsin and lamprey rhodopsin were immunohistochemically localized in the dorsal and ventral regions of the pineal organ, respectively. The two pigments were localized in distinct photoreceptor cells throughout the pineal organ, namely the dorsal and ventral regions as well as the peripheral region, which corresponds to the dorso-ventral border region. The ratio of the number of lamprey parapinopsin-containing cells to lamprey rhodopsin-containing cells around the peripheral region was higher than in the central region. Electron-microscopic analysis revealed that lamprey parapinopsin-containing dorsal cells have outer segments and synaptic ribbons similar to those of ventral photoreceptor cells. However, unlike lamprey rhodopsin-containing cells, lamprey parapinopsin-containing cells connected with each other in a wide area of dorsal and peripheral portions and made direct contact with ganglion cells,mainly in the peripheral portion. These results suggest that UV light information captured by lamprey parapinopsin-containing photoreceptor cells is converged and directly transmitted to chromatic-type ganglion cells in the peripheral region to generate antagonistic chromatic responses.
Diurnal and nocturnal prey luring of a colorful predator
Authors: Chuang Chih-Yen , Yang En-Cheng , Tso I-Min 
Published: October 2007

SUMMARY
While animal color signaling has been studied for decades, we have little knowledge of the role conspicuous body coloration plays in the nocturnal context. In this study we explored animal color signaling in both diurnal and nocturnal contexts to arrive at a more comprehensive understanding of its function. We quantified how the brightly colored giant wood spiders Nephila pilipes are viewed by nocturnal insects, and performed field manipulations to assess the function of a spider's coloration in both diurnal and nocturnal conditions. Seen through the eyes of moths, the conspicuous body parts of spiders are quite distinctive from the vegetation background. The presence of N. pilipes significantly increased the diurnal as well as the nocturnal prey interception rates of their webs, but these rates were significantly reduced when the conspicuous color signals of N. pilipes were altered by black paint. A comparison of the diurnal and nocturnal hunting performances of spiders showed that their conspicuous coloration had a higher luring effect under dim light conditions. These results demonstrate that the conspicuous body coloration of N. pilipes functions as a visual lure to attract both diurnal and nocturnal prey. It seems that nocturnal insects are the major target of this colorful sit-and-wait predator. We suggest that the selection pressure to effectively exploit the color vision of nocturnal prey could be one of the major forces driving the evolution of spider coloration.
The use of distal rhynchokinesis by birds feeding in water
Authors: Estrella Sora M. , Masero José A. 
Published: October 2007

SUMMARYThe use of distal rhynchokinesis, which consists of the movement of the distal part of the upper jaw with respect to the cranium, is well documented in long-billed shorebirds (Scolopacidae), commonly being associated with the deep probing feeding method. However, the functional and evolutionary significance of distal rhynchokinesis and other cranial kinesis is unclear. We report for the first time the use and occurrence of distal rhynchokinesis in wild long-billed shorebirds feeding on small prey items suspended in water. We tested whether prey size in captive dunlins Calidris alpinainfluences the occurrence of distal rhynchokinesis during feeding and also whether its use affects foraging efficiency. We found that wild dunlin, curlew sandpiper Calidris ferruginea, sanderling Calidris alba and little stint Calidris minuta commonly use distal rhynchokinesis to strike, capture and transport small prey items. Prey size influenced the occurrence of distal rhynchokinesis during the transport phase, with this type of cranial kinesis being more frequently used with larger prey. The rhynchokinesis protraction angle (a measure of bill tip elevation) during prey strike and transport was affected by prey size, and bill gape was modulated through the use of distal rhynchokinesis in relation to prey size. Finally,the use of distal rhynchokinesis throughout intra-oral prey transport was related to shorter transport times, which improved foraging efficiency. We conclude that distal rhynchokinesis is a mechanism that could contribute to the flexible feeding behaviour of long-distance migratory shorebirds,enhancing small prey profitability and so improving foraging efficiency, and may have played a role in the evolutionary radiation of Scolopacidae(Charadrii).
Molecular cloning, phylogeny and localization of AgNHA1: the first Na+/H+ antiporter (NHA) from a metazoan,Anopheles gambiae
Authors: Rheault Mark R. , Okech Bernard A. , Keen Stephen B. W. , Miller Melissa M. , Meleshkevitch Ella A. , Linser Paul J. , Boudko Dmitri Y. , Harvey William R. 
Published: October 2007

SUMMARYWe have cloned a cDNA encoding a new ion transporter from the alimentary canal of larval African malaria mosquito, Anopheles gambiae Giles sensu stricto. Phylogenetic analysis revealed that the corresponding gene is in a group that has been designated NHA, and which includes(Na+ or K+)/H+ antiporters; so the novel transporter is called AgNHA1. The annotation of current insect genomes shows that both AgNHA1 and a close relative, AgNHA2, belong to the cation proton antiporter 2 (CPA2) subfamily and cluster in an exclusive clade of genes with high identity from Aedes aegypti, Drosophila melanogaster, D. pseudoobscura, Apis mellifera and Tribolium castaneum. Although NHA genes have been identified in all phyla for which genomes are available, no NHA other than AgNHA1 has previously been cloned,nor have the encoded proteins been localized or characterized.The AgNHA1 transcript was localized in An. gambiae larvae by quantitative real-time PCR (qPCR) and in situ hybridization. AgNHA1 message was detected in gastric caeca and rectum, with much weaker transcription in other parts of the alimentary canal. Immunolabeling of whole mounts and longitudinal sections of isolated alimentary canal showed that AgNHA1 is expressed in the cardia, gastric caeca, anterior midgut, posterior midgut, proximal Malpighian tubules and rectum, as well as in the subesophageal and abdominal ganglia.A phylogenetic analysis of NHAs and KHAs indicates that they are ubiquitous. A comparative molecular analysis of these antiporters suggests that they catalyze electrophoretic alkali metal ion/hydrogen ion exchanges that are driven by the voltage from electrogenic H+ V-ATPases. The tissue localization of AgNHA1 suggests that it plays a key role in maintaining the characteristic longitudinal pH gradient in the lumen of the alimentary canal of An. gambiae larvae.
G protein activation by uncaging of GTP-γ-S in the leech giant glial cell
Authors: Hirth Ingo C. , Britz Frank C. , Deitmer Joachim W. 
Published: October 2007

SUMMARY
Glial cells can be activated by neurotransmitters viametabotropic, G protein-coupled receptors. We have studied the effects of`global' G protein activation by GTP-γ-S on the membrane potential,membrane conductance, intracellular Ca2+ and Na+ of the giant glial cell in isolated ganglia of the leech Hirudo medicinalis. Uncaging GTP-γ-S (injected into a giant glial cell as caged compound) by moderate UV illumination hyperpolarized the membrane due to an increase in K+ conductance. Uncaging GTP-γ-S also evoked rises in cytosolic Ca2+ and Na+, both of which were suppressed after depleting the intracellular Ca2+ stores with cyclopiazonic acid (20 μmol l–1). Uncaging inositol-trisphosphate evoked a transient rise in cytosolic Ca2+ and Na+ but no change in membrane potential. Injection of the fast Ca2+ chelator BAPTA or depletion of intracellular Ca2+ stores did not suppress the membrane hyperpolarization induced by uncaging GTP-γ-S. Our results suggest that global activation of G proteins in the leech giant glial cell results in a rise of Ca2+-independent membrane K+conductance, a rise of cytosolic Ca2+, due to release from intracellular stores, and a rise of cytosolic Na+, presumably due to increased Na+/Ca2+ exchange.
Effects of perch diameter and incline on the kinematics, performance and modes of arboreal locomotion of corn snakes (Elaphe guttata)
Authors: Astley Henry C. , Jayne Bruce C. 
Published: October 2007

SUMMARYAnimals moving through arboreal habitats face several functional challenges, including fitting onto and moving on cylindrical branches with variable diameters and inclines. In contrast to lizards and primates, the arboreal locomotion of snakes is poorly understood, despite numerous snake species being arboreal. We quantified the kinematics and performance of corn snakes (Elaphe guttata) moving on seven cylinders (diameters 1.6–21 cm) with five inclines (horizontal, ±45° and±90°) and through horizontal tunnels of corresponding widths. When perches were inclined at either 45° or 90°, snakes were unable to move uphill or downhill on the larger diameters. None of the locomotion on perches conformed to any previously described mode of limbless locomotion. On horizontal and uphill perches snakes performed a variant of concertina locomotion with periodic stopping and gripping. When moving downhill, snakes often slid continuously while grasping the perch to reduce their speed. Mean forward velocity decreased both with increased incline and with increased perch diameter, contrary to the beneficial effect of increased diameter on the speeds of lizards. Both tunnel width and perch diameter had widespread and similar effects on kinematics. When perches and tunnels were narrower, the snakes had more lateral bends at shallower angles. The numerous effects of perch diameter on kinematics and the similarity to tunnel concertina locomotion emphasize the importance of fit as a limitation in arboreal locomotion of snakes. However, the slower speeds on horizontal perches compared to tunnels also suggest that balance and grip may further limit locomotor performance.
Honeybees perform optimal scale-free searching flights when attempting to locate a food source
Authors: Reynolds Andrew M. , Smith Alan D. , Reynolds Don R. , Carreck Norman L. , Osborne Juliet L. 
Published: October 2007

SUMMARY
The foraging strategies used by animals are key to their success in spatially and temporally heterogeneous environments. We hypothesise that when a food source at a known location ceases to be available, flying insects will exhibit search patterns that optimise the rediscovery of such resources. In order to study these searching patterns, foraging honeybees were trained to an artificial feeder that was then removed, and the subsequent flight patterns of the bees were recorded using harmonic radar. We show that the flight patterns have a scale-free (Lévy-flight) characteristic that constitutes an optimal searching strategy for the location of the feeder. It is shown that this searching strategy would remain optimal even if the implementation of the Lévy-flights was imprecise due, for example, to errors in the bees'path integration system or difficulties in responding to variable wind conditions. The implications of these findings for animal foraging in general are discussed.
Effects of photoperiod history on body mass and energy metabolism in Brandt's voles (Lasiopodomys brandtii)
Authors: Lu Qin , Zhong Wen-Qin , Wang De-Hua 
Published: October 2007

SUMMARYMany small mammals respond to seasonal changes in photoperiod via alterations in morphology, physiology and behaviour. In the present study, we tested the hypothesis that the preweaning (from embryo to weaning) photoperiod experience can affect subsequent development in terms of body mass and thermogenesis. Brandt's voles (Lasiopodomys brandtii) were gestated and reared to weaning under either a short (SD, 8 h:16 h L:D) or a long photoperiod (LD, 16 h:8 h L:D) at a constant ambient temperature (23°C). At weaning, male juveniles were either maintained in their initial photoperiod or transferred to the alternative photoperiod for 8 weeks. Postweaning SD voles had a lower body mass but higher thermogenic capacity compared with LD voles. At the same time, preweaning photoperiod conditions had long-lasting effects on thermogenic capacity later in life. Serum leptin concentration was positively correlated with body mass and body fat mass, whereas it was negatively correlated with energy intake and uncoupling protein 1 content in brown adipose tissue. Our results suggest that postweaning development in terms of body mass and thermogenesis is predominantly influenced by the postweaning photoperiod, while the preweaning photoperiod experience could chronically modify thermogenesis but not body mass. Furthermore, serum leptin,acting as a potential adipostatic signal, may be involved in the regulation of both energy intake and energy expenditure.
Towards a Global Regime on Contract Compliance?
Authors: Erridge Andrew , Fee Ruth 
Published: October 2007

English
This article assesses arguments on contract compliance in relation to national and international regional policies. A wide range of policy types from no policy to combinations of employment equity and contract compliance are found, suggesting that prospects for the development of a global regime through the World Trade Organisation are not favourable. This will result in increased business costs from varying national and regional requirements, use of social and employment conditions to protect national contractors, and social dumping. An approach combining governmental and business action is proposed to overcome the problems facing intergovernmental agreement on norms and specific measures.
Housing Policy: does it have a future?
Authors: Malpass Peter 
Published: October 2007

English
This article begins by looking at the idea that housing policy in Britain has come to an end, at least in terms of the formulations that were generally accepted throughout much of the post1945 period. Reference is made to two particular contributions, by Bramley and Kleinman, who both argue that housing can now be understood as an adjunct of other social programme areas, such as social security and regeneration. The article then goes on to consider arguments for believing that there are still serious genuine housing problems to be tackled. This leads into a review of the UK labour government’s stance on housing and its performance during its first 18 months in office. The article concludes with some modest proposals for the development of effective housing policy measures beyond the end of the century, arguing that housing is so important in terms of its impact on life chances that it should be at the heart of social policy.
Midregional Pro-A-Type Natriuretic Peptide and Carboxy-Terminal Provasopressin May Predict Prognosis in Community-Acquired Pneumonia
Authors: Masiá Mar , Papassotiriou Jana , Morgenthaler Nils G , Hernández Ildefonso , Shum Conrado , Gutiérrez Félix 
Published: October 2007

AbstractBackground: Markers to better assess severity of disease in patients with community-acquired pneumonia (CAP) would help improve medical care of this condition. The hemodynamic biomarkers carboxy-terminal provasopressin (CT-proAVP; copeptin) and midregional proatrial natriuretic peptide (MR-proANP) are increased under septic conditions, in which MR-proANP has been described as a prognostic predictor. We aimed to explore the diagnostic accuracy of MR-proANP and CT-proAVP to predict mortality in patients with CAP.Methods: We conducted a prospective observational study of patients with CAP. We measured biomarkers in serum samples obtained at diagnosis and performed univariate and multivariate analyses to identify potential predictors of mortality.Results: CT-proAVP and MR-proANP concentrations were measured in 173 patients. We found a positive correlation between pneumonia severity index (PSI) and MR-proANP (rs = 0.68, P &lt;0.0001) and between PSI and CT-proAVP (rs = 0.44, P &lt;0.0001). Median (interquartile range) CT-proAVP and MR-proANP values were 8.2 (5.3–16.8) and 73.6 (44.6–144.0) pmol/L, respectively. Nonsurvivors had significantly higher MR-proANP and CT-proAVP than survivors (median 259.0 vs 71.8 pmol/L, P = 0.01, and 24.9 vs 8.1 pmol/L, P = 0.03, respectively). In multivariate analysis including PSI, procalcitonin, C-reactive protein, lipopolysaccharide-binding protein, CT-proAVP, and MR-proANP concentrations, only CT-proAVP remained an independent predictor of death (odds ratio 1.05, P = 0.007). Cutoff values of &gt;18.9 pmol/L for CT-proAVP and &gt;227 pmol/L for MR-proANP showed the highest diagnostic accuracy to predict mortality.Conclusions: CT-proAVP and MR-proANP may be used to predict prognosis in patients with CAP.
Association of C-Reactive Protein with Surrogate Measures of Insulin Resistance among Nondiabetic US Adults: Findings from National Health and Nutrition Examination Survey 1999–2002
Authors: Meng Yuan-Xiang , Ford Earl S , Li Chaoyang , Quarshie Alexander , Al-Mahmoud Ahmad M , Giles Wayne , Gibbons Gary H , Strayhorn Gregory 
Published: October 2007

Abstract
Background: Increased C-reactive protein (CRP) concentration and insulin resistance (IR) are associated with increased rates of adverse cardiovascular events. We sought to examine the relationship of CRP with surrogate measures of IR among nondiabetic adults in the US.
Methods: We conducted analyses using data from the National Health and Nutrition Examination Survey 1999–2002. We analyzed a nationally representative sample of 2514 men and nonpregnant women age ≥20 years who were non-Hispanic white, non-Hispanic black, or Mexican American.
Results: After adjustment for age, sex, race/ethnicity, smoking status, systolic blood pressure, and serum concentrations of HDL cholesterol, LDL cholesterol, and triglyceride, CRP was significantly associated with 10 IR measures (all P values &lt;0.01). The strength of the association attenuated after further adjustment for waist circumference (change in adjusted regression coefficients ranging from 60.0% to 75.1%). The association of CRP with each IR surrogate was similar (standardized regression coefficient ranges from 0.06 to 0.09). The association of CRP (&gt;3 vs &lt;1 mg/L) with the homeostasis model for assessment of IR (≥75th vs &lt;75th percentile) was statistically significant among people with a body mass index ≥30 kg/m2 (odds ratio, 2.6; 95% CI, 1.3–5.1) or with a body mass index &lt;25 kg/m2 (odds ratio, 2.5; 95% CI, 1.5–4.2).
Conclusions: CRP was significantly associated with the surrogate measures of IR among nondiabetic adults. Obesity may play an important role in the association of CRP with IR in this nationally representative sample.