bluuebunny/crossref_metadata_2025_split huggingface dataset:
Do precocial mammals develop at a faster rate? A comparison of rates of skull development in Sigmodon fulviventer and Mus musculus domesticus
Authors: Zelditch Miriam Leah , Lundrigan Barbara L. , David Sheets H. , Garland Theodore 
Published: June 2003

Abstract
Variation in neonatal maturity among mammals is often explained by variation in gestation length, but species may also differ in developmental rate, a quantity that is difficult to measure because the conventional formalism makes two important and potentially unrealistic assumptions: (1) ontogeny of form can be described by a single line, and (2) species have the same ontogeny of form. We examine two species, one precocial (Sigmodon fulviventer), the other altricial (Mus musculus domesticus), and find that neither assumption is met. Therefore, we introduce an alternative metric, the rate of shape differentiation away from the average neonate. We find that S. fulviventer has a lower developmental rate than M. m. domesticus; consequently, while more mature at birth, S. fulviventer loses ground to M. m. domesticus over time. Surprisingly, despite differences in gestation length and developmental rate, these species reach developmental and life-history milestones at nearly identical degrees of skull shape maturity.
Colour polymorphism in birds: causes and functions
Authors: Galeotti P. , Rubolini D. , Dunn P. O. , Fasola M. 
Published: June 2003

Abstract
We studied polymorphism in all species of birds that are presently known to show intraspecific variation in plumage colour. At least three main mechanisms have been put forward to explain the maintenance of polymorphism: apostatic, disruptive and sexual selection. All of them make partly different predictions. Our aims were to investigate evolutionary causes and adaptive functions of colour polymorphism by taking into account a number of ecological and morphological features of polymorphic species. Overall, we found 334 species showing colour polymorphism, which is 3.5% of all bird species. The occurrence of colour polymorphism was very high in Strigiformes, Ciconiiformes, Cuculiformes and Galliformes. Phylogenetically corrected analysis using independent contrasts revealed that colour polymorphism was maximally expressed in species showing a daily activity rhythm extended to day/night, living in both open and closed habitats. All these findings support the hypothesis that colour polymorphism probably evolved under selective pressures linked to bird detectability as affected by variable light conditions during activity period. Thus, we conclude that selective agents may be prey, predators and competitors, and that colour polymorphism in birds may be maintained by disruptive selection.
Species richness in agamid lizards: chance, body size, sexual selection or ecology?
Authors: Stuart-Fox Devi , Owens Ian P. F. 
Published: June 2003

Abstract
Why does species richness vary so greatly across lineages? Traditionally, variation in species richness has been attributed to deterministic processes, although it is equally plausible that it may result from purely stochastic processes. We show that, based on the best available phylogenetic hypothesis, the pattern of cladogenesis among agamid lizards is not consistent with a random model, with some lineages having more species, and others fewer species, than expected by chance. We then use phylogenetic comparative methods to test six types of deterministic explanation for variation in species richness: body size, life history, sexual selection, ecological generalism, range size and latitude. Of eight variables we tested, only sexual size dimorphism and sexual dichromatism predicted species richness. Increases in species richness are associated with increases in sexual dichromatism but reductions in sexual size dimorphism. Consistent with recent comparative studies, we find no evidence that species richness is associated with small body size or high fecundity. Equally, we find no evidence that species richness covaries with ecological generalism, latitude or range size.
Caste fate conflict in swarm-founding social Hymenoptera: an inclusive fitness analysis
Authors: Wenseleers T. , Ratnieks F. L. W. , Billen J. 
Published: June 2003

Abstract
A caste system in which females develop into morphologically distinct queens or workers has evolved independently in ants, wasps and bees. Although such reproductive division of labour may benefit the colony it is also a source of conflict because individual immature females can benefit from developing into a queen in order to gain greater direct reproduction. Here we present a formal inclusive fitness analysis of caste fate conflict appropriate for swarm-founding social Hymenoptera. Three major conclusions are reached: (1) when caste is self-determined, many females should selfishly choose to become queens and the resulting depletion of the workforce can substantially reduce colony productivity; (2) greater relatedness among colony members reduces this excess queen production; (3) if workers can prevent excess queen production at low cost by controlled feeding, a transition to nutritional caste determination should occur. These predictions generalize results derived earlier using an allele-frequency model [Behav. Ecol. Sociobiol. (2001) 50: 467] and are supported by observed levels of queen production in various taxa, especially stingless bees, where caste can be either individually or nutritionally controlled.
Sex-specific reaction norms to intraspecific larval competition in the mosquito Aedes aegypti
Authors: Bedhomme S. , Agnew P. , Sidobre C. , Michalakis Y. 
Published: June 2003

Abstract
As the relationship between a given life-history trait and fitness is not necessarily the same for the two sexes, an ‘intersexual ontogenetic conflict’ may arise. We analysed the phenotypic reaction to intraspecific larval competition of the mosquito, Aedes aegypti, asking: (i) Do both sexes pay the cost of competition with the same life-history traits and are they equal competitors? (ii) Is there a specific cost of competition beyond sharing food resources? We found that competition incurs a specific cost that was expressed differently by the two sexes. Indeed, each sex maintained the more important life-history trait(s) for their fitness (developmental time for males and body weight and size for females) at the expense of other traits, thus minimizing the effects of competition on their fitness. The competition exerted by females was estimated as being more intense, probably linked with the greater importance of body size for their fitness.
Noncoding plastid trnT-trnF sequences reveal a well resolved phylogeny of basal angiosperms
Authors: Borsch T. , Hilu K. W. , Quandt D. , Wilde V. , Neinhuis C. , Barthlott W. 
Published: June 2003

Abstract
Recent contributions from DNA sequences have revolutionized our concept of systematic relationships in angiosperms. However, parts of the angiosperm tree remain unclear. Previous studies have been based on coding or rDNA regions of relatively conserved genes. A phylogeny for basal angiosperms based on noncoding, fast-evolving sequences of the chloroplast genome region trnT-trnF is presented. The recognition of simple direct repeats allowed a robust alignment. Mutational hot spots appear to be confined to certain sectors, as in two stem-loop regions of the trnL intron secondary structure. Our highly resolved and well-supported phylogeny depicts the New Caledonian Amborella as the sister to all other angiosperms, followed by Nymphaeaceae and an Austrobaileya–Illicium–Schisandra clade. Ceratophyllum is substantiated as a close relative of monocots, as is a monophyletic eumagnoliid clade consisting of Piperales plus Winterales sister to Laurales plus Magnoliales. Possible reasons for the striking congruence between the trnT-trnF based phylogeny and phylogenies generated from combined multi-gene, multi-genome data are discussed.
Inactivation of phosphorylase is a major component of the mechanism by which insulin stimulates hepatic glycogen synthesis
Authors: Aiston Susan , Coghlan Matthew P. , Agius Loranne 
Published: June 2003

Multiple signalling pathways are involved in the mechanism by which insulin stimulates hepatic glycogen synthesis. In this study we used selective inhibitors of glycogen synthase kinase‐3 (GSK‐3) and an allosteric inhibitor of phosphorylase (CP‐91149) that causes dephosphorylation of phosphorylase a, to determine the relative contributions of inactivation of GSK‐3 and dephosphorylation of phosphorylase a as alternative pathways in the stimulation of glycogen synthesis by insulin in hepatocytes.GSK‐3 inhibitors (SB‐216763 and Li+) caused a greater activation of glycogen synthase than insulin (90% vs. 40%) but a smaller stimulation of glycogen synthesis (30% vs. 150%). The contribution of GSK‐3 inactivation to insulin stimulation of glycogen synthesis was estimated to be less than 20%. Dephosphorylation of phosphorylase a with CP‐91149 caused activation of glycogen synthase and translocation of the protein from a soluble to a particulate fraction and mimicked the stimulation of glycogen synthesis by insulin. The stimulation of glycogen synthesis by phosphorylase inactivation cannot be explained by either inhibition of glycogen degradation or activation of glycogen synthase alone and suggests an additional role for translocation of synthase. Titrations with the phosphorylase inactivator showed that stimulation of glycogen synthesis by insulin can be largely accounted for by inactivation of phosphorylase over a wide range of activities of phosphorylase a. We conclude that a signalling pathway involving dephosphorylation of phosphorylase a leading to both activation and translocation of glycogen synthase is a critical component of the mechanism by which insulin stimulates hepatic glycogen synthesis. Selective inactivation of phosphorylase can mimic insulin stimulation of hepatic glycogen synthesis.
Functional dissection of the Schizosaccharomyces pombe Holliday junction resolvase Ydc2: in vivo role in mitochondrial DNA maintenance
Authors: Sigala Barbara , Tsaneva Irina R. 
Published: June 2003

The crystal structure of the Schizosaccharomyces pombe Holliday junction resolvase Ydc2 revealed significant structural homology with the Escherichia coli resolvase RuvC but Ydc2 contains a small triple helical bundle that has no equivalent in RuvC. Two of the α‐helices that form this bundle show homology to a putative DNA‐binding motif known as SAP. To investigate the biochemical function of the triple‐helix domain, truncated Ydc2 mutants were expressed in E. coli and in fission yeast. Although the truncated proteins retained all amino‐acid residues that map to the structural core of RuvC including the catalytic site, deletion of the SAP motif alone or the whole triple‐helix domain of Ydc2 resulted in the complete loss of resolvase activity and impaired significantly the binding of Ydc2 to synthetic junctions in vitro. These results are in full agreement with our proposal for a DNA‐binding role of the triple‐helix motif [Ceschini et al. (2001) EMBO J. 20, 6601–6611]. The biological effect of Ydc2 on mtDNA in yeast was probed using wild‐type and several Ydc2 mutants expressed in Δydc2 S. pombe. The truncated mutants were shown to localize exclusively to yeast mitochondria ruling out a possible role of the helical bundle in mitochondrial targeting. Cells that lacked Ydc2 showed a significant depletion of mtDNA content. Plasmids expressing full‐length Ydc2 but not the truncated or catalytically inactive Ydc2 mutants could rescue the mtDNA ‘phenotype’. These results provide evidence that the Holliday junction resolvase activity of Ydc2 is required for mtDNA transmission and affects mtDNA content in S. pombe.
Fracture care of friend and foe during World War I
Authors: Kirkup John 
Published: June 2003

Background:  In the early years of trench warfare, compound lower limb fractures caused by gunshot missiles prompted the ­questioning of traditional splintage techniques and established evacuation methods. These prejudiced recovery and delayed surgery, often by many days, causing a high mortality rate especially for open femoral fractures. Importantly, battle weaponry was modified by differences in climate and terrain in Mesopotamia, Gallipoli, the Alps and the Northern European plain, to manifest differences in wound pathology. In Flanders, the static situation limited simple bullet wounds and launched a high percentage of jagged shell ­fragment injuries complicated by tissue destruction, in‐driven clothing and metal contaminated with mud, lethal bacteria and spores. From no‐mans‐land, soldiers with arm fractures scrambled back unaided, with tibial fractures they might hobble between two comrades, but with femoral fractures they were helpless unless stretcher bearers arrived. Often they did not, or only after a lull in fighting, by which time death from blood loss or exposure supervened. Even on a stretcher, poor fracture immobilization and long arduous carries added to shock and mortality. Remedies to these deficiencies and observations by Australasian, Austrian, British, Canadian, French, German, South African and American surgeons are noted.Conclusions:  Trained to treat bullet wounds in open terrain, many military medical organizations were slow to adjust to the novel challenges associated with trench warfare. However, from 1917 well‐trained stretcher bearers, efficient application of the Thomas splint, better control of haemorrhage and more rapid evacuation with motorized ambulances reduced deaths, amputation rates and long‐term disability significantly.
Effects of heterotopic bone formation on outcome after hip arthroplasty
Authors: Neal Bruce 
Published: June 2003

Background:  Heterotopic bone formation (HBF) is well established as a frequent complication of major hip surgery, but its importance as a cause of impaired postoperative outcome is uncertain.Methods:  A systematic overview of all studies that reported the association of HBF with the risk of impaired range of movement, pain or poor function, late after hip arthroplasty.Results:  A computer‐based search identified 37 relevant studies that included 10 826 individuals. There were 30 studies (8305 participants) that assessed the association between HBF and range of movement, 14 studies (7420 participants) that assessed the association between HBF and pain and 16 studies (5918 participants) that assessed the association between HBF and function. Overall, there was a clear positive association of HBF with the risk of an impaired range of movement at the hip joint and with the risk of a poor functional outcome. The association of HBF with pain was unclear. There was evidence of effects of mild‐to‐moderate HBF on the postoperative range of movement.Conclusions:  These results suggest that mild‐to‐moderate HBF, not just severe HBF, can influence outcome after major hip ­surgery. HBF may therefore be a more frequent cause of postoperative symptomatology than is generally believed. It is possible that effective prophylactic regimens will improve outcomes in large numbers of patients.
Nasal fractures: a study comparing local and general anaesthesia techniques
Authors: Rajapakse Yosanta , Courtney Mark , Bialostocki Adam , Duncan Gary , Morrissey Graham 
Published: June 2003

Background:  The objective of the present study was to examine the outcome of nasal fracture reduction under both local anaesthesia and general anaesthesia techniques.Methods:  Patient records were obtained from clinic lists of patients attending the otolaryngology (ORL) outpatient unit at ­Wellington Hospital or the plastic surgical unit at Hutt Hospital over a 24‐month period. To meet criteria for inclusion, patients had to have an isolated nasal deformity, be aged 14 years or older and be at least 6 months post reduction. Functional and aesthetic results were assessed using subjective and objective end outcome measures. A questionnaire was developed and used to assess subjective outcomes. The number of patients proceeding to open operative correction was used for the objective measure, which included septoplasty, septorhinoplasty or rhinoplasty.Results:  A total of 197 patients had nasal fractures manipulated over this period. One hundred and seven were manipulated under general anaesthesia (GA) and 90 were manipulated under local anaesthesia (LA). The questionnaire completion rate was 66%. Patient demographics were statistically similar between the two groups. There was no statistical difference in patients" subjective assessment of outcome with treatment by GA or LA. More patients preferred to have their fracture manipulated under GA but this was not ­statistically significant. There was no significant difference between GA and LA groups in progression to open operative correction.Conclusions:  Both LA and GA appear to be acceptable and satisfactory methods of anaesthesia in the reduction of simple displaced nasal fracture.
Single institution's initial experience with sentinel lymph node biopsy in breast cancer patients
Authors: Yong W. S. , Wong C. Y. , Lee J. S. Y. , Soo K. C. , Tan P. H. , Goh A. S. W. 
Published: June 2003

Background:  The sentinel lymph node is the first draining node from a cancer‐bearing area and is therefore the first to manifest metastasis. In breast cancer it has been shown to predict the axillary status. Axillary dissection provides information determining prognosis and need for adjuvant therapy but carries a certain morbidity. Our aim was to determine the feasibility of detecting the sentinel node in a teaching hospital and whether the sentinel node accurately predicts the axillary status.Methods:  All patients with stage I and II breast cancer and non‐palpable axillary nodes were eligible, including those with previous excision biopsy. We excluded pregnant women, those with previous axillary surgery and women with advanced breast cancer with enlarged axillary nodes. The sentinel node was detected with technetium‐99m‐labelled tin colloid and vital blue dye and removed, and axillary clearance was performed.Results:  A total of 312 patients were examined from August 1996 to December 1998. The mean age was 53 years (range 28−83) and mean tumour size 2.6 cm (range 0.2−9.0). The detection rate of the sentinel node was 86%. The sentinel lymph node predicted the axillary status with a sensitivity of 83% and specificity of 100%. The false‐negative rate was 16.7%.Conclusions:  Detection of the sentinel lymph node is feasible and it can accurately predict the nodal status of the axilla. ­However, the high false‐negative rate precludes as yet the use of sentinel lymph node biopsy in replacing axillary clearance as the standard of care for breast cancer.
Anatomical justification of Belghiti's ‘liver hanging manoeuvre’ in right hepatectomy with anterior approach
Authors: Meng William C.S. , Shao C.X. , Mak K.L. , Lau Patrick Y.Y. , Yeung Y.P. , Yip Andrew W.C. 
Published: June 2003

Background:  In cases of right hepatectomy for huge tumour encroaching onto the diaphragm, the ‘anterior approach’ is the most common surgical procedure undertaken. The ‘liver hanging manoeuvre’ has been described previously as an adjunct to this pro­cedure. It involves the dissection of a retrohepatic avascular plane anterior to the surface of the inferior vena cava. A tape is then passed through and the liver is resected under suspension.Methods:  Cadaveric specimens were used to identify the structural relationship of the avascular plane and also to determine whether it is truly avascular.Results:  Thirteen cases were analysed. The mean length of the avascular tunnel was 6.4 ± 1.0 cm. The median number of accessory hepatic veins within the tunnel was two (zero to three). At the caudal half of the tunnel, the median number of veins was two (zero to three). As for the cranial half of the tunnel, there were two cases with one vein in each.Conclusions:  The key to the liver hanging manoeuvre is to develop the retrohepatic tunnel. However, our study showed that it is not absolutely avascular. During the blind dissection, there is a chance of damaging a retrohepatic vein. This may result in troublesome haemorrhage within the confines of the tunnel. Video‐assisted dissection of this region may help in visualisation, and hence control, in order to avoid bleeding.
Solid pseudopapillary tumour of the pancreas
Authors: Ng Kheng Hong , Tan Puay Hoon , Thng Choon Hua , Ooi London Lucien 
Published: June 2003

Background:  Solid pseudopapillary tumour of the pancreas is a rare pancreatic tumour that occurs predominantly in women, with very few cases reported in men. This is a tumour with low malignancy potential and surgical resection usually results in cure.Methods:  A retrospective review of our experience with solid pseudopapillary tumours between April 1992 and December 2000 was undertaken.Results:  Six patients were identified including one male patient. The median age was 30 years, with four patients presenting with abdominal pain and discomfort and two patients presenting with palpable abdominal masses. The mean tumour diameter was 10.2 cm and the lesions were found mainly in the body and tail of the pancreas. Only one patient had tumour at the pancreatic head. One patient had a locally invasive disease and another had peritoneal spread. None of the patients received adjuvant therapy. The mean follow up was 3.8 years (range: 1.5−10.0) and all patients were free of recurrence to date.Conclusion:  SPT is a rare tumour with an unclear origin that has a distinct histology and presentation. Although preoperative diagnosis is difficult by computed tomography, magnetic resonance imaging may potentially improve this situation. In general, this is a tumour of very low malignant potential and long‐term survival is excellent after resection of the tumour.
Sir William Turner and his studies on the mammalian placenta
Authors: Magee Reginald 
Published: June 2003

William Turner was appointed Professor of Anatomy at the University of Edinburgh in 1867, and from 1903 until his death in 1916, he was Principal and Vice‐Chancellor. He was an outstanding teacher and many of those he taught went on to occupy chairs of anatomy. He published widely on anatomical subjects and one of his interests was comparative anatomy and physiology of the placenta.This paper takes a brief look at Turner's studies on the anatomical structure of the placenta, its comparative anatomy, his thoughts about its physiology and its place in the evolutionary process. At the time, these lectures constituted an anatomical and physiological classic.At the time Turner prepared his lectures, which were delivered in 1875 and 1876, little was known about the gestatory process in marsupials or monotremes. These mammals have a very brief period of intrauterine gestation and placentation and mention is made of studies that have been done in recent times on this subject.