bluuebunny/crossref_metadata_2025_split huggingface dataset:
Bi-directional route learning in wood ants
Authors: Graham Paul , Collett Thomas S. 
Published: August 2006

SUMMARYSome ants and bees readily learn visually guided routes between their nests and feeding sites. They can learn the appearance of visual landmarks for the food-bound or homeward segment of the route when these landmarks are only present during that particular segment of their round trip. We show here that wood ants can also acquire landmark information for guiding their homeward path while running their food-bound path, and that this information may be picked up, when ants briefly reverse direction and retrace their steps for a short distance. These short periods of looking back tend to occur early in route acquisition and are more frequent on homeward than on food-bound segments.
Actions of kinin peptides in the stomatogastric ganglion of the crabCancer borealis
Authors: Saideman Shari R. , Christie Andrew E. , Torfs Pieter , Huybrechts Jurgen , Schoofs Liliane , Nusbaum Michael P. 
Published: August 2006

SUMMARYTo fully understand neuronal network operation, the influence of all inputs onto that network must be characterized. As in most systems, many neuronal and hormonal pathways influence the multifunctional motor circuits of the crustacean stomatogastric ganglion (STG), but the actions of only some of them are known. Therefore, we characterized the influence of the kinin peptide family on the gastric mill (chewing) and pyloric (filtering of chewed food)motor circuits in the STG of the crab Cancer borealis. The kinins are myoactive in arthropods and they occur within the arthropod central nervous system (CNS), but their CNS actions are not well characterized in any species. The pevkinins were first identified in the shrimp Penaeus vannamei,but they have yet to be studied in the STG of any species. We identified kinin-like immunolabeling (KLI) in the pericardial organs (POs) in C. borealis, but there was no KLI within the STG. The POs are a major source of hormonal influence on the STG. Pevkinin peptides activated the pyloric circuit and they caused a modest increase in the speed of ongoing pyloric rhythms. This modest influence on cycle speed resulted in part from pevkinin excitation of the lateral pyloric neuron, whose strengthened inhibitory synapse onto the pyloric pacemaker neurons limited the pevkinin-mediated increase in cycle speed. The pevkinin excitation of the pyloric rhythm was not strong enough to interfere with the previously documented, gastric mill rhythm-mediated weakening of the pyloric rhythm. Pevkinin also had little influence on the gastric mill rhythm. These results indicate that the kinin peptides have distinct and selective modulatory actions on the pyloric rhythm.
Testing an ecophysiological mechanism of morphological plasticity in pupfish and its relevance to conservation efforts for endangered Devils Hole pupfish
Authors: Lema Sean C. , Nevitt Gabrielle A. 
Published: August 2006

SUMMARYImperiled species that have been translocated or established in captivity can show rapid alterations in morphology and behavior, but the proximate mechanisms of such phenotypic changes are rarely known. Devils Hole pupfish(Cyprinodon diabolis) are endemic to a single desert pool and are characterized by a small body, large head and eyes, and lack of pelvic fins. To lessen the risk of extinction, additional populations of C. diabolis were established in artificial refuges. Yet, pupfish in these refuges rapidly shifted to a larger body, smaller head and eyes, and greater body depth. Here we examined how food availability and temperature, which differ between these habitats, influence morphological development in closely related Amargosa River pupfish (Cyprinodon nevadensis amargosae). We were interested in knowing whether these environmental factors could developmentally shift Amargosa River pupfish toward the morphology typical of pupfish in Devil's Hole. By regulating food ration, we created groups of pupfish with low, medium and high growth rates. Pupfish with low growth showed proportionally larger head and eyes, smaller body depth, and reduction in pelvic fin development. Elevated temperature further inhibited pelvic fin development in all treatments. Pupfish in the low growth group also showed reduced levels of thyroid hormone, suggesting a possible physiological mechanism underlying these morphological changes. To test this mechanism further, pupfish were reared with goitrogens to pharmacologically inhibit endogenous thyroid hormone production. Pupfish given goitrogens developed larger heads and eyes, shallower bodies, and reduced pelvic fins. Taken together, our results suggest that changes in environmental factors affecting the growth and thyroid hormone status of juvenile pupfish may play a developmental role in generating the morphological differences between C. diabolis in Devil's Hole and the refuges. These findings illustrate the need to incorporate a mechanistic understanding of phenotypic plasticity into conservation strategies to preserve imperiled fishes.
Perturbation of auditory feedback causes systematic perturbation in vocal structure in adult cotton-top tamarins
Authors: Egnor S. E. Roian , Iguina Carmen G. , Hauser Marc D. 
Published: August 2006

SUMMARY
Auditory feedback is critical for the development and maintenance of speech in humans. In contrast, studies of nonhuman primate vocal production generally report that subjects show little reliance on auditory input. We examined the extent to which cotton-top tamarin (Saguinus oedipus) vocal production is sensitive to perturbation of auditory feedback by manipulating the predictability of presentation of a 1 s burst of white noise during the production of the species-specific contact call, the combination long call(CLC). We used three experimental conditions: the Begin condition, in which white noise was presented only during the first half of a recording session,the End condition, in which white noise was presented only in the last half,and the Random condition, in which each call had a 50% probability of receiving white noise playback throughout the recording session, making the auditory feedback unpredictable. In addition we recorded calls before and after the experimental series (Baseline condition) to determine whether any changes induced by modification of auditory feedback persisted. Results showed that playback of white noise during the production of the CLC produced changes in the temporal structure of the CLC: calls were shorter and had fewer pulses,indicating that modification of auditory feedback can interrupt vocal production. In addition, calls that received modified feedback were louder and had longer inter-pulse intervals than those that did not, consistent with an adaptive response to the masking effect of white noise playback. The magnitude of this compensatory effect and the interruption rate were both sensitive to whether the feedback modification occurred at the beginning or end of the experimental session: early feedback produced less interruption and more compensation. Finally, when auditory feedback modification was unpredictable,adaptive changes were observed in both calls that received modified feedback and those that received normal feedback, suggesting that tamarins can generate an expectation of noise playback and increase vocal amplitude in anticipation of masking.
Odour-evoked responses to queen pheromone components and to plant odours using optical imaging in the antennal lobe of the honey bee droneApis melliferaL.
Authors: Sandoz Jean-Christophe 
Published: August 2006

SUMMARYThe primordial functional role of honey bee males (drones) is to mate with virgin queens, a behaviour relying heavily on the olfactory detection of queen pheromone. In the present work I studied olfactory processing in the drone antennal lobe (AL), the primary olfactory centre of the insect brain. In drones, the AL consists of about 103 ordinary glomeruli and four enlarged glomeruli, the macroglomeruli (MG). Two macroglomeruli (MG1 and MG2) and approximately 20 ordinary glomeruli occupy the anterior surface of the antennal lobe and are thus accessible to optical recordings. Calcium imaging was used to measure odour-evoked responses to queen pheromonal components and plant odours. MG2 responded specifically to the main component of the queen mandibular pheromone, 9-ODA. The secondary components HOB and HVA each triggered activity in one, but not the same, ordinary glomerulus. MG1 did not respond to any of the tested stimuli. Plant odours induced signals only in ordinary glomeruli in a combinatorial manner, as in workers. This study thus shows that the major queen pheromonal component is processed in the most voluminous macroglomerulus of the drone antennal lobe, and that plant odours,as well as some queen pheromonal components, are processed in ordinary glomeruli.
Correlation between thermotolerance and membrane properties inParamecium aurelia
Authors: Sasaki Toshiaki , Konoha Yoshimi , Toyoda Taichi , Yasaka Yuta , Przybos Eva , Nakaoka Yasuo 
Published: August 2006

SUMMARYThe relationship between thermotolerance and membrane properties was studied by using a ciliated protozoan, Paramecium aurelia. P. aurelia is a complex of sibling species termed `syngens' whose cell morphology appear similar on microscopic examination. From the comparison of tolerance to increasing temperature among 14 syngens of P. aurelia,we selected syngens 2 and 3 as low thermotolerant examples, and syngens 8 and 10 as high thermotolerant examples. The membrane resistance of high thermotolerant syngens measured by injection of a constant inward current was greater than that of low thermotolerant syngens. Membrane fluidity measurements of living cells using the fluorescent dye,6-lauroyl-2-dimethylaminonaphtalene (laurdan) showed that the fluidity at the cultured temperature was decreased in high thermotolerant syngens compared to that of low thermotolerant syngens. However, when the temperature was increased to the killing temperature of each syngens, the fluidity was increased to almost the same level irrespective of syngen. Furthermore,analysis of fatty acids extracted from whole cells showed that the ratios of unsaturated to saturated fatty acids was smaller in high thermotolerant syngens than in low thermotolerant syngens. These results suggest that the thermotolerance of P. aurelia syngens is determined by the membrane fluidity which is related to the fatty acids composition.
Effective elastic modulus of isolated gecko setal arrays
Authors: Autumn K. , Majidi C. , Groff R. E. , Dittmore A. , Fearing R. 
Published: August 2006

SUMMARY
Conventional pressure sensitive adhesives (PSAs) are fabricated from soft viscoelastic materials that satisfy Dahlquist's criterion for tack with a Young's modulus (E) of 100 kPa or less at room temperature and 1 Hz. In contrast, the adhesive on the toes of geckos is made of β-keratin, a stiff material with E at least four orders of magnitude greater than the upper limit of Dahlquist's criterion. Therefore, one would not expect aβ-keratin structure to function as a PSA by deforming readily to make intimate molecular contact with a variety of surface profiles. However, since the gecko adhesive is a microstructure in the form of an array of millions of high aspect ratio shafts (setae), the effective elastic modulus(Eeff) is much lower than E of bulkβ-keratin. In the first test of the Eeff of a gecko setal adhesive, we measured the forces resulting from deformation of isolated arrays of tokay gecko (Gekko gecko) setae during vertical compression, and during tangential compression at angles of +45° and-45°. We tested the hypothesis that Eeff of gecko setae falls within Dahlquist's criterion for tack, and evaluated the validity of a model of setae as cantilever beams. Highly linear forces of deformation under all compression conditions support the cantilever model. Eeff of setal arrays during vertical and +45°compression (along the natural path of drag of the setae) were 83±4.0 kPa and 86±4.4 kPa (means ± s.e.m.), respectively. Consistent with the predictions of the cantilever model, setae became significantly stiffer when compressed against the natural path of drag: Eeff during -45° compression was 110±4.7 kPa. Unlike synthetic PSAs, setal arrays act as Hookean elastic solids; setal arrays function as a bed of springs with a directional stiffness, assisting alignment of the adhesive spatular tips with the contact surface during shear loading.
Reconceptualizing System Usage: An Approach and Empirical Test
Authors: Burton-Jones Andrew , Straub Detmar W. 
Published: August 2006

Although DeLone, McLean, and others insist that system usage is a key variable in information systems research, the system usage construct has received little theoretical scrutiny, boasts no widely accepted definition, and has been operationalized by a diverse set of unsystematized measures. In this article, we present a systematic approach for reconceptualizing the system usage construct in particular nomological contexts. Comprising two stages, definition and selection, the approach enables researchers to develop clear and valid measures of system usage for a given theoretical and substantive context. The definition stage requires that researchers define system usage and explicate its underlying assumptions. In the selection stage, we suggest that system usage be conceptualized in terms of its structure and function. The structure of system usage is tripartite, comprising a user, system, and task, and researchers need to justify which elements of usage are most relevant for their study. In terms of function, researchers should choose measures for each element (i.e., user, system, and/or task) that tie closely to the other constructs in the researcher's nomological network. To provide evidence of the viability of the approach, we undertook an empirical investigation of the relationship between system usage and short-run task performance in cognitively engaging tasks. The results support the benefits of the approach and show how an inappropriate choice of usage measures can lead researchers to draw opposite conclusions in an empirical study. Together, the approach and the results of the empirical investigation suggest new directions for research into the nature of system usage, its antecedents, and its consequences.
Bertolotti’s syndrome
Authors: Quinlan J. F. , Duke D. , Eustace S. 
Published: August 2006

Bertolotti’s syndrome is characterised by anomalous enlargement of the transverse process(es) of the most caudal lumbar vertebra which may articulate or fuse with the sacrum or ilium and cause isolated L4/5 disc disease. We analysed the elective MR scans of the lumbosacral spine of 769 consecutive patients with low back pain taken between July 2003 and November 2004. Of these 568 showed disc degeneration. Bertolotti’s syndrome was present in 35 patients with a mean age of 32.7 years (15 to 60). This was a younger age than that of patients with multiple disc degeneration, single-level disease and isolated disc degeneration at the L4/5 level (p ≤ 0.05). The overall incidence of Bertolotti’s syndrome in our study was 4.6% (35 of 769). It was present in 11.4% (20 patients) of the under-30 age group. Our findings suggest that Bertolotti’s syndrome must form part of a list of differential diagnoses in the investigation of low back pain in young people.
Is secondary radiological follow-up of infants with a family history of developmental dysplasia of the hip necessary?
Authors: Arumilli B. R. B. , Koneru P. , Garg N. K. , Davies R. , Saville S. , Sampath J. , Bruce C. 
Published: August 2006

The practice of regular radiological follow-up of infants with a positive family history of developmental dysplasia of the hip is based on the widespread belief that primary acetabular dysplasia is a genetic disorder which can occur in the absence of frank subluxation or dislocation. We reviewed all infants who were involved in our screening programme for developmental dysplasia of the hip, between November 2002 and January 2004, and who had a normal clinical and ultrasound examination of the hip at six to eight weeks of age, but who, because of a family history of developmental dysplasia of the hip, had undergone further radiography after an interval of 6 to 12 months. The radiographs of 89 infants were analysed for signs of late dysplasia of the hip and assessed independently by three observers to allow for variability of measurement. There were 11 infants (11%) lost to follow-up. All the patients had normal radiographs at the final follow-up and none required any intervention. We therefore question the need for routine radiological follow-up of infants with a positive family history of developmental dysplasia of the hip, but who are normal on clinical examination and assessment by ultrasound screening when six to eight weeks old.
Does salvage and tranexamic acid reduce the need for blood transfusion in revision hip surgery?
Authors: Phillips S. J. , Chavan R. , Porter M. L. , Kay P. R. , Hodgkinson J. P. , Purbach B. , Reddick A. Hoad , Frayne J. M. 
Published: August 2006

We carried out a retrospective case-control study in 80 patients who underwent a revision total hip replacement. Group A (40 patients) received tranexamic acid and intra-operative cell salvage. Group B (40 patients) was a matched control group and did not receive this management. Each group was divided into four subgroups: revision of both components, revision of both components with bone grafting, revision of the acetabular component with or without bone graft, and revision of the femoral component with or without bone graft. In group A the total number of units transfused was 52, compared with 139 in group B, representing a reduction in blood usage of 62.5%. The mean amount of blood transfused from cell salvage in each group was 858 ml (113 to 2100), 477 ml (0 to 2680), 228 ml (75 to 315) and 464 ml (120 to 1125), respectively. There was a significant difference in the amount of blood returned between the groups (p < 0.0001). In group A, 22 patients needed transfusion and in group B, 37 (p < 0.0001). A cost analysis calculation showed a total revenue saving of £70 000 and a potential saving throughout our facility of £318 288 per year. Our results show that a significant reduction in blood transfusion can be made using combined cell salvage and tranexamic acid in revision surgery of the hip.
Exposure of the head of the radius using the Wrightington approach
Authors: Stanley J. K. , Penn D. S. , Wasseem M. 
Published: August 2006

Surgical access to the head of the radius is usually performed through a lateral approach. We present an alternative technique through a modified posterior approach which was developed following dissections of 22 human cadavers. An osteotomy of the supinator tuberosity was performed and reflected as a single unit with the attached annular ligament. Excellent exposure of the head of the radius was achieved, replacement of the head was undertaken and the osteotomy site repaired. The elbows were stable and had a full range of movement. The approach was then carried out on 13 patients for elective replacement of the head and was found to be safe and reproducible. In the patient group all osteotomies united, the elbows were stable and had an improved range of supination and pronation. There was no change in flexion and extension of the elbow. Complications included a haematoma and a reflex sympathetic dystrophy. The modified posterior approach provides excellent access to the head and neck of the radius, gives good stability of the elbow and allows early mobilisation of the joint.
Homologous blood transfusion is not required in surgery for adolescent idiopathic scoliosis
Authors: Verma R. R. , Williamson J. B. , Dashti H. , Patel D. , Oxborrow N. J. 
Published: August 2006

We studied 70 consecutive patients with adolescent idiopathic scoliosis who underwent corrective surgery. They were divided into two groups. In the study group of 38 patients one or more modern blood-conservation measures was used peri-operatively. The 32 patients in the control group did not have these measures. Both groups were similar in regard to age, body-weight, the number of levels fused and the type of surgery. Only two patients in the study group were transfused with homologous blood and these transfusions were ‘off-protocol’. Wastage of autologous pre-donated units was minimal (6 of 83 units). By contrast, all patients in the control group were transfused with homologous blood. In the study group there was a significant decrease (p = 0.005) in the estimated blood loss when all the blood-conservation methods were used. The use of blood-conservation measures, the lowering of the haemoglobin trigger for transfusion and the education of the entire team involved in the care of the patient can prevent the need for homologous blood transfusion in patients undergoing surgery for adolescent idiopathic scoliosis.
The novel use of resorbable Vicryl mesh for in vivo tendon reconstruction to a metal prosthesis
Authors: Pendegrass C. J. , Oddy M. J. , Sundar S. , Cannon S. R. , Goodship A. E. , Blunn G. W. 
Published: August 2006

We examined the mechanical properties of Vicryl (polyglactin 910) mesh in vitro and assessed its use in vivo as a novel biomaterial to attach tendon to a hydroxyapatite-coated metal implant, the interface of which was augmented with autogenous bone and marrow graft. This was compared with tendon re-attachment using a compressive clamp device in an identical animal model. Two- and four-ply sleeves of Vicryl mesh tested to failure under tension reached 5.13% and 28.35% of the normal ovine patellar tendon, respectively. Four-ply sleeves supported gait in an ovine model with 67.05% weight-bearing through the operated limb at 12 weeks, without evidence of mechanical failure. Mesh fibres were visible at six weeks but had been completely resorbed by 12 weeks, with no evidence of chronic inflammation. The tendon-implant neoenthesis was predominantly an indirect type, with tendon attached to the bone-hydroxyapatite surface by perforating collagen fibres.
Five- to 12-year follow-up of a hydroxyapatite-coated, cementless total knee replacement in young, active patients
Authors: Tai C. C. , Cross M. J. 
Published: August 2006

We carried out a prospective study of 118 hydroxyapatite-coated, cementless total knee replacements in patients who were ≤ 55 years of age and who had primary (92; 78%) or post-traumatic (26; 22%) osteoarthritis. The mean period of follow-up was 7.9 years (5 to 12.5). The Knee Society clinical scores improved from a pre-operative mean of 98 (0 to 137) to a mean of 185 (135 to 200) at five years, and 173 (137 to 200) at ten years. There were two revisions of the tibial component because of aseptic loosening, and one case of polyethylene wear requiring further surgery. There was no osteolysis or progressive radiological loosening of any other component. At 12 years, the overall rate of implant survival was 97.5% (excluding exchange of spacer) and 92.1% (including exchange of spacer). Cementless total knee replacement can achieve excellent long-term results in young, active patients with osteoarthritis. In contrast to total hip replacement, polyethylene wear, osteolysis and loosening of the prosthesis were not major problems for these patients, although it is possible that this observation could change with longer periods of follow-up.