bluuebunny/crossref_metadata_2025 huggingface dataset:
Multiple biopsies of normal‐looking urothelium in patients with superficial bladder cancer: Are they necessary?
Authors: FUJIMOTO NAOHIRO , HARADA SHUJI , TERADO MICHIKAZU , SATO HIDEKI , MATSUMOTO TETSURO
Published: November 2003

Background:  The objective of the study presented here was to assess the usefulness and indications of multiple biopsies of normal‐appearing urothelium in patients with superficial bladder cancer.

Methods:  Between December 1996 and December 2002, multiple biopsies of normal‐appearing bladder mucosa were performed in 100 patients with superficial bladder transitional cell carcinoma. Biopsy specimens were taken from seven different sites in females and nine different sites in males.

Results:  In eight of 100 patients, bladder cancers were detected in the biopsy specimens. Three cases were Ta and five were Tis. All of the five patients with carcinoma in situ (CIS) in their biopsy specimens had multiple papillary broad‐base tumors and positive urinary cytology. The detection ratio of CIS in patients with these findings was 17.9% (5/28). No concomitant CIS was detected in the 72 patients who had a solitary tumor, pedunculated tumor(s), or negative urinary cytology.

Conclusion:  Multiple mucosal biopsies of normal‐appearing urothelium are not necessary for all patients with superficial bladder cancer. They are, however, necessary for patients with multiple papillary broad‐base tumors and positive urinary cytology.
Litterfall dynamics and nitrogen use efficiency in two evergreen temperate rainforests of southern Chile
Authors: Pérez Cecilia A. , Armesto Juan J. , Torrealba Cristian , Carmona Martín R.
Published: November 2003

Abstract  In unpolluted regions, where inorganic nitrogen (N) inputs from the atmosphere are minimal, such as remote locations in southern South America, litterfall dynamics and N use efficiency of tree species should be coupled to the internal N cycle of forest ecosystems. This hypothesis was examined in two evergreen temperate forests in southern Chile (42°30′S), a mixed broad‐leaved forest (MBF) and a conifer forest (CF). Although these forests grow under the same climate and on the same parental material, they differ greatly in floristic structure and canopy dynamics (slower in the CF). In both forests, biomass, N flux, and C/N ratios of fine litterfall were measured monthly from May 1995 to March 1999. There was a continuous litter flux over the annual cycle in both forests, with a peak during autumn in the CF. In the MBF, litterfall decreased during spring. In both forests, the C/N ratios of litterfall varied over the annual cycle with a maximum in autumn. Annual litterfall biomass flux (Mean ± SD = 3.3 ± 0.5 vs 2.0 ± 0.5 Mg ha−1) and N return (34.8 ± 16 vs 9.1 ± 2.8 kg N ha−1) were higher in the MBF than in the CF. At the ecosystem level, litterfall C/N was lower in the MBF (mean C/N ratio = 60.1 ± 15, n = 3 years) suggesting decreased N use efficiency compared with CF (mean C/N ratio = 103 ± 19.6, n = 3 years). At the species level, subordinated (subcanopy) tree species in the MBF had significantly lower C/N ratios (<50) of litterfall than the dominant trees in the CF and MBF (>85). The litterfall C/N ratio and percentage N retranslocated were significantly correlated and were lower in the MBF. The higher net N mineralization in soils of the MBF is related to a lower N use efficiency at the ecosystem and species level.
Leaf traits and herbivore selection in the field and in cafeteria experiments
Authors: Pérez‐Harguindeguy Natalia , Díaz Sandra , Vendramini Fernanda , Cornelissen Johannes H. C. , Gurvich Diego E. , Cabido Marcelo
Published: November 2003

Abstract  Despite the vast diversity and complexity of herbivores, plants and their interactions, most authors agree that a small number of components of leaf quality affect preference by generalist herbivores in a predictable way. However, herbivore preference is determined not only by intrinsic plant attributes and herbivore biology but also by the environmental context. Within this framework, we aimed to analyse general interspecific trends in the association between herbivory and leaf traits over a wide range of angiosperms from central Argentina. We (i) tested for consistent associations between leaf traits, consumption in the field, and preference of generalist invertebrate herbivores in cafeteria experiments; (ii) assessed how well herbivore preferences in cafeterias matched leaf consumption in the field; and (iii) developed a simple conceptual model linking leaf traits, herbivore preference in cafeterias and consumption in the field. In general, we found that tender leaves with higher nutritional quality were preferred by herbivores, both in the field and in cafeteria experiments. According to our model, this relationship between field and cafeteria consumption and leaf quality is observed when generalist herbivores and plants of high accessibility are considered. However, differences between leaf consumption in the field and in cafeteria experiments can also be found. At least two reasons can account for this: (i) specialized plant–herbivore relationships often occur in the field, whereas cafeteria experiments tend to consider only one or a few generalist herbivores; (ii) different plant species growing in the field often differ in their degree of accessibility to herbivores, whereas in cafeteria experiments all species are equally accessible. Our results add new evidence to a growing consensus that, although herbivory in the field is determined by many factors, consistent patterns of differential susceptibility to foliar feeders can be found in leaves differing in nutritional quality and thus in resource‐use strategy.
Effects of cover reduction on mulgara Dasycercus cristicauda (Marsupialia: Dasyuridae), rodent and invertebrate populations in central Australia: Implications for land management
Authors: Masters Pip , Dickman Chris R. , Crowther Mathew
Published: November 2003

Abstract  This study investigates the effect of cover reduction on the mulgara, Dasycercus cristicauda, a small marsupial classified as vulnerable to extinction, which occurs in areas of central Australia dominated by hummock grasslands. Loss or degradation of spinifex has been implicated in population declines of this species previously, but the importance of cover in maintaining quality habitat remains speculative. To determine the effect on D. cristicauda of cover reduction, caused by the harvesting of spinifex, we monitored population changes and changes in prey resources (rodents and invertebrates) before and after spinifex harvesting took place at a site near the Ayers Rock Resort, Northern Territory, Australia. Ten plots, each of 8.75 ha, were established and sampled from May 1994 to October 1995. Harvesting took place on five plots in August 1994, which reduced spinifex cover from 46 to 21% and the amount of spinifex >0.25 m high from 42 to 2%. Harvesting did not significantly affect the number of D. cristicauda known to be alive or captured despite other studies indicating that cover is an important habitat attribute. There was also no evidence that cover reduction impacted on the biomass of the invertebrate food resources. However, there was a significant reduction in the number of rodents captured. The lack of a response to cover reduction by D. cristicauda is possibly because the cover of Triodia remained high enough (above 15%) to sustain animals, and harvested areas were relatively small. This study therefore suggests that D. cristicauda can tolerate a moderate local reduction in cover of its preferred habitat. However, it remains possible that other land use practices that cause severe reduction of cover (including clearing for mining or fire prevention, grazing which may result in spinifex reduction through trampling, and fire management) will have more dramatic effects on D. cristicauda. Evaluation of such effects should be a priority for future research.
Does foraging mode influence life history traits? A comparative study of growth, maturation and survival of two species of sympatric snakes from south‐eastern Australia
Authors: Webb Jonathan K. , Brook Barry W. , Shine Richard
Published: November 2003

Abstract  Theory predicts that compared with active searchers, ambush foragers should have lower rates of energy intake, slower growth, and higher survival rates. We tested these predictions with data on two species of sympatric, saurophagous, small‐bodied, viviparous elapid snakes: the broad‐headed snake, Hoplocephalus bungaroides, and the small‐eyed snake, Rhinoplocephalus nigrescens. Demographic parameters and growth curves for both species were estimated from a long‐term (9 years) mark‐recapture study in Morton National Park, south‐eastern Australia. The ambush predator (H. bungaroides) displayed slower juvenile growth and later maturation (5 years for males, 6 years for females) than did the active forager (R. nigrescens, 3 years). Litter sizes were similar in both species, but reproductive frequency was higher in R. nigrescens (90–100%) than in H. bungaroides (50%). Juvenile survival was lower in the active searcher (31%) than in the ambush forager (55%), but adult survivorship was similar (74% vs 82%). Our results support the hypothesis that ambush foragers display ‘slow’ life history traits, but additional phylogenetically independent comparisons are needed to evaluate the generality of this pattern.
Characterizing fish–habitat associations in streams as the first step in ecological restoration
Authors: Bond N. R. , Lake P. S.
Published: November 2003

Abstract  Habitat availability is often regarded as the primary factor that limits population and community recovery in degraded ecosystems, and physical habitat is thus often targeted in restoration. The identification of which habitat(s) to attempt to restore is a critical step in the restoration process, but one for which there is often a paucity of useful information. Here we examine the distribution of fish in three lowland streams in Victoria, Australia, that have been degraded by severe sedimentation. We aim to identify habitats that are associated with high abundances of native fish, and that thus might be appropriate to target in habitat restoration. Associations between native fish abundances and physical habitat characteristics were examined at three spatial scales (among streams, among sites and within sites) to determine the types of habitat to which fish respond, and the scales over which these responses occur. Of the four species of native fish found in the streams, three (Galaxias olidus Günther, Gadopsis marmoratus (Richardson) and Nanoperca australis Günther) showed significant habitat associations at small spatial scales (i.e. within sites). In particular, these species were generally found in deeper water, and in close proximity to cover (typically either coarse or fine woody debris or vegetation). Differences in habitat availability among sites and streams were less influential, except in the case of G. marmoratus, which was completely absent from both the ephemeral streams. Although our results suggest that these species collectively respond to habitat at several spatial scales, fish distributions were allied to the presence of habitat structure at the scale of metres, the smallest spatial scale examined. We hypothesize that fish abundances are currently limited by the low availability of habitat at these small spatial scales. It may therefore be possible to increase fish abundances in these creeks by augmenting the amount of available habitat via stream restoration.
Effect of abiotic factors on the foraging strategy of the orb‐web spider Argiope keyserlingi (Araneae: Araneidae)
Authors: Herberstein M. E. , Fleisch A. F.
Published: November 2003

Abstract  Environmental conditions such as light level, background contrast and temperature might influence a spider's prey capture success and risk of predation. Thus it may often be advantageous for spiders to adjust web‐building behaviour in response to variation in these environmental conditions. This hypothesis was examined in a study of the construction of webs and web decorations (conspicuous strands of silk at the hub of the web) of the orb‐web spider Argiope keyserlingi. Web decorations are thought to have one or more separate functions. They may attract prey, deter predators or advertise the web to oncoming birds, thus preventing web damage. In this series of experiments, relationships between weather parameters and the construction of webs and web decorations were considered. In complementary laboratory experiments, A. keyserlingi spiders were exposed to two different light levels (700 and 90 lx), background contrasts (black and white) and temperature conditions (20 and 26°C). Of the available weather parameters, only temperature was significantly related to web decorating behaviour but not to web size. In the laboratory, temperature also influenced web‐decorating behaviour, and spiders in dim light (700 lx) constructed larger webs and longer decorations. Background contrast did not significantly alter web size or web decorations. These data suggest that when prey availability is reduced at low temperatures, spiders may use web decorations to attract prey to the web. Similarly, in dim light, spiders may build more and larger decorations to increase the visual signal to approaching prey or to advertise the web to oncoming birds.
Too much vacuum‐assisted closure
Authors: Dieu Tam , Leung Michael , Leong James , Morrison Wayne , Cleland Heather , Archer Brett , Oppy Andrew
Published: November 2003

There has been an explosion in the use of the vacuum‐assisted closure device since 1997. Selectively and judiciously used, it is a valuable tool. However, we are concerned by the expanding list of ‘indications’ for its use. Prolonged applications, frequently several weeks, at the expense of early surgical reconstruction, might compromise the outcome in selected cases. We report four cases that illustrate this problem and stress the importance of timely surgical reconstruction utilizing the range of reconstructive techniques available as well as vacuum‐assisted closure dressing.
Use of a polymeric device to deliver growth factors to a healing fracture
Authors: Wong Wicky C. F. , Yu Yan , Wallace Andrew L. , Gianoutsos Mark P. , H. Sonnabend David , Walsh William R.
Published: November 2003

Background:  Fracture healing is a cascade of events regulated by systemic and local factors. Local growth factors are believed to play an integral role. The present study evaluates the effects of basic fibroblast growth factor (bFGF) and insulin‐like growth factor‐1 (IGF‐1) using a controlled delivery system in a closed rodent femoral fracture model.

Methods:  Female Wistar rats (n = 144) were used in the present study. Animals were randomly allocated to six groups, with each group divided into three time‐points of 2, 4 and 8 weeks. Two groups had growth factor administered. The others had no operation or sham operations. Growth factors were delivered to the fracture site using a specialised delivery system. This consisted of a Kirschner‐wire coated with ethylene vinyl acetate co‐polymer embedded with growth factors, inserted as an intramedullary nail. Fractures were effected with a three‐point bending device. Femurs were tested in four‐point bending and structural properties of peak load and stiffness were obtained from the load‐displacement graphs. Specimens were prepared for qualitative analysis under a light microscope and using immunohistochemistry, specimens were analysed for expression of bFGF, IGF‐1 and transforming growth factor β (TGF‐β).

Results:  The growth factor‐treated groups exhibited larger calluses at 2 and 4 weeks. Four‐point bending showed weaker structural properties (stiffness and peak load) at 4 weeks in both growth factor‐treated groups. Administration of bFGF or IGF‐1 increased the ratio of cartilaginous to mesenchymal tissues in the fracture callus compared with non‐treated animals at 2 and 4 weeks. Immunostaining intensity and distribution of both growth factors in the treated groups was greater than the non‐treated groups.

Conclusion:  Exogenous delivery of bFGF or IGF‐1 alters the course of fracture healing.
Transfer function index: is it a reliable method for vein graft surveillance?
Authors: Tan Chuan Ping , Civil Ian
Published: November 2003

Introduction:  Duplex ultrasound scanning is currently the best available non‐invasive method for vein graft surveillance. However, it is expensive and its results are highly operator dependent. The aim of the present study is to compare, another non‐invasive method of graft surveillance, the transfer function index (TFI), with duplex ultrasound scanning in identifying significant stenoses in infrainguinal saphenous vein bypass grafts.

Methods:  Initially a retrospective pilot study was carried out between 1 January and 30 June 2002. Patients were identified from the vascular surgical operation database. The ultrasound report and TFI result of each patient were reviewed. Then a prospective comparative study was carried out between 1 July and 31 December 2002. Duplex ultrasound and TFI studies were undertaken at the 3 month interval. Comparisons were made between the accuracy and predictive value of ultrasound versus TFI in assessing significant graft stenosis.

Results:  In the present retrospective study TFI measurement was significantly lower in the at‐risk grafts than in the normal grafts (P = 0.001). In the prospective group TFI was again found to be significantly lower in the at‐risk group (mean TFI 0.86) than in the normal group (mean TFI 1.064, P = 0.001). The sensitivity and specificity of the TFI were 92% and 97%, respectively. The accuracy of TFI was calculated to be 98%.

Conclusion:  TFI is an accurate non‐invasive method of vascular graft surveillance. TFI can be carried out in the vascular clinic and is quick and inexpensive. Normally TFI could replace duplex ultrasound surveillance, with ultrasound being reserved for those with an abnormal TFI.
Fixation of femoral fractures in multiple‐injury patients with combined chest and head injuries
Authors: Nau Thomas , Aldrian Silke , Koenig Franz , Vécsei Vilmos
Published: November 2003

Background:  The purpose of the present paper was to study the effects of a femoral shaft fracture and its early stabilization on the morbidity, mortality, and outcome of multiple‐injury patients with combined blunt head and chest trauma. The clinical course of patients was analysed using a prospectively gathered data base.

Methods:  Out of 352 multitrauma patients, from September 1992 to June 2000, we identified 28 patients with combined blunt chest and head trauma (abbreviated injury scale ≥ 2) and a femoral fracture as the study group. A total of 120 patients with combined chest and head trauma but without femoral fracture formed the control group. Parameters examined included injury severity, injury pattern, haemodynamics at admission, mortality, duration of ventilation, length of stay in intensive care unit, and outcome.

Results:  There were no significant differences regarding the demographics and injury severity (injury severity score) between the two groups. No significant differences were found in terms of mortality, duration of ventilation\intensive care unit stay and outcome. Injury severity (P < 0.0001), age (P = 0.0153), and haemodynamics at admission (P = 0.0036) were shown to have a significant effect on mortality and outcome. Injury severity (P < 0.0001) and age (P = 0.017) had a significant effect on the duration of ventilation\intensive care unit stay.

Conclusions:  The present study suggests that a femoral shaft fracture and its early stabilization in a multitrauma patient with combined chest and head injury do not adversely affect mortality and outcome and supports aggressive surgical management for these patients.
Measuring clinical audit and peer review practice in a diverse health care setting
Authors: Spigelman Allan D. , Swan Judith
Published: November 2003

Background:  A measurement system was devised to determine the extent of clinical audit and peer review across the Hunter Area Health Service, to compare changes over time and to assess the effect of the implementation of a policy on the conduct of patient safety meetings.

Methods:  Two surveys were conducted over consecutive years (2001, 2002). A scoring system was developed based on a 12 point questionnaire. Ten points were given for a ‘yes’ response and zero for a ‘no’ response. Points were also given for frequency of meetings. Statistical analysis was by the Mann−Whitney U‐test. The questionnaire included items on clinical indicators, management of issues arising and whether meetings are multidisciplinary, chaired and points for action minuted and followed up.

Results:  One‐hundred and five units provided data for the 2001 survey (100% response rate) and 109 units provided data for the 2002 survey (100% response rate). There was a significant increase in the median score in the 2002 survey (median 101; interquartile range 72−113) when compared with the 2001 Survey (median 91; interquartile range 51−110; P = 0.016). There was an improvement of 9% in units scoring in the highest quartile (90−120 points) and a decrease of 5% in units scoring in the lowest quartile (0−29 points).

Conclusions:  This methodology allows for the quantitative measurement of audit and peer review activities across clinical units. It might assist clinicians, professional colleges and departments of health in the further development of the recertification\revalidation process.
Experience in the endoscopic management of large colonic polyps
Authors: Church James M.
Published: November 2003

Background:  Large colonic polyps present a particular challenge to endoscopists because of the risks of significant haemorrhage, perforation, inadequate polypectomy, or trying to snare an unrecognized cancer. The alternative to endoscopic therapy of large polyps is surgical resection and although minimally invasive techniques are available, risks are significant. Although neither surgery nor endoscopy is a perfect way of treating large colonic polyps, endoscopic resection is usually tried first. Most series of endoscopic polypectomies are small, include both rectal and colonic polyps and have varying size and shape criteria. The purpose of the present study is to describe a large consecutive series of colonic polyps evaluated endoscopically, to determine the chances of performing a safe, effective endoscopic polypectomy.

Methods:  All colonic polyps>20 mm in maximum dimension assessed during colonoscopy from 1989 to 2002 were reviewed. Rectal polyps were excluded. Demographic data for the patients were abstracted, as were data regarding the outcomes of polyp assessment and treatment. Primary end‐points were: the need for surgical resection, the incidence of postpolypectomy complications and the persistence of the index polyp at follow up. Independent variables included the endoscopically assessed size of the polyps, the year in which the polypectomy took place, the shape of the polyps and their location within the colon.

Results:  During the period under review 311 large polyps were removed from 252 different patients. Of these, 263 polyps were removed endoscopically and 48 polyps were removed surgically. An additional 18 endoscopically removed polyps ultimately needed surgery for recurrence or malignancy. There were no deaths but 19 complications of endoscopic polypectomy (17 late haemorrhage and two postpolypectomy syndrome). At first follow up, 22% of polyps had persisted, this decreased to 14% at second follow up and 7% at third. Complications were more common in right sided polyps and in flat or sessile lesions. Pedunculated polyps never persisted or recurred and had the lowest rate of surgery. Larger polyps had higher rates of advanced histology, complications, polyp persistence and the need for surgery.

Conclusions:  Polyp size, location and shape influence the results of endoscopic resection of large colonic polyps. Polyps>30 mm in maximum diameter are significantly more advanced histologically but also significantly more difficult to treat successfully than those <30 mm. However, size alone is rarely a contraindication to endoscopic resection.
Use of a retrograde femoral nail in a patient with McCune−Albright syndrome
Authors: Garvan John D. , Trantalis John N.
Published: November 2003

McCune−Albright Syndrome is a rare condition characterized by endocrine abnormalities, precocious puberty, pigmented skin lesions and polyostotic fibrous dysplasia with consequent fractures and limb deformity. Patients with this syndrome might have had multiple operations on a limb and might also have extensive internal fixation in‐situ. We review the case of a 41‐year‐old woman with McCune−Albright syndrome, who presented with a pathological fracture of her left femur below a long plate and screws. Our management of this challenging problem included the use of a retrograde femoral nail, which, because of the need to retain pre‐existing internal fixation, had to be locked proximally through a hole in a femoral plate. This technique, combined with reaming, and thus bone grafting of the fracture, and also perioperative infusions of pamidronate, allowed an early recovery and return to premorbid function for the patient. In the present study we detail our technique and discuss its advantages over other possible methods of treatment.
Biomechanical analysis of five fixation techniques used in glenohumeral arthrodesis
Authors: Miller Bruce S. , Harper Wade P. , Gillies R. Mark , Sonnabend David H. , Walsh William R.
Published: November 2003

Background:  The purpose of the present study is to compare five fixation techniques in shoulder fusion. The most common complications resulting from shoulder fusion, non‐union and unacceptable arm position, might reflect a failure to achieve rigid fixation during the surgical procedure.

Methods:  Twenty‐five shoulder fusions were carried out on human cadaveric specimens using the following techniques: screw fixation, external fixation, external fixation supplemented with screw fixation, single plate fixation and double plate fixation. Each specimen was tested on a servohydraulic machine to determine stiffness.

Results:  There was a statistically significant difference in bending and torsional stiffness between all five fixation techniques. Normalized bending (B) and torsional stiffness (T), in descending order, were: double plate (B = 1.00, T = 1.00), single plate (B = 0.77, T = 0.89), external fixation with screws (B = 0.68, T = 0.74), external fixation alone (B = 0.40, T = 0.53), and screws alone (B = 0.13, T = 0.26).

Conclusion:  The risk of the most common complications resulting from shoulder fusion might be minimized if these biomechanical findings are applied to surgical decision making.
Tumour involvement of the re‐excision specimen following clear local excision of breast cancer with positive margins
Authors: Ooi Corinne W. L. , Serpell Jonathan W. , Rodger Alan
Published: November 2003

Background:  Breast conservation surgery and subsequent radiotherapy is an acceptable method of treating breast cancer. Complete excision of the primary tumour is important to minimize the risk of local recurrence. Re‐excision is usually carried out if the initial primary tumour excision shows positive margins. However, a significant proportion of re‐excision specimens are negative for tumour. The aim of the present study was to identify factors predicting a histologically positive re‐excision specimen.

Methods:  The case records of all patients with invasive and in situ breast cancer referred to the William Buckland Radiotherapy Centre between January 1996 and December 2001 were reviewed. The factors evaluated were patient age, whether or not tumours were detected by screening mammography, use of hook‐wire needle localization, whether tumours were marked with orientating sutures, histopathological characteristics of the tumour and involvement of axillary nodes. Univariate analysis was performed.

Results:  In the study period, a total of 1128 patients were reviewed. Of these, 742 underwent breast conservation surgery. Twenty‐nine (3.9%) of the 742 had positive surgical margins and underwent re‐excision. Data were insufficient for six, leaving 23 patients eligible for the study. The number of patients entering the study was small, limiting the statistical analysis. Of these, 21 patients had invasive cancer and two patients had ductal carcinoma in situ only. Of 23 re‐excisions, 11(48%) contained residual tumour. Univariate analysis of the data revealed no significant factors that were likely to predict tumour in the re‐excision specimen. The local recurrence after re‐excision in patients with positive margins was 4.3%.

Conclusion:  The results suggest that it is not possible to predict which patients will have tumour in the re‐excision specimen. However, approximately 50% of re‐excision specimens showed residual cancer. Therefore it is recommended that all excisions with positive margins need further surgery.
Competitive coexistence in spatially structured environments: a synthesis
Authors: Amarasekare Priyanga
Published: November 2003

Theoretical developments in spatial competitive coexistence are far in advance of empirical investigations. A framework that makes comparative predictions for alternative hypotheses is a crucial element in narrowing this gap. This review attempts to synthesize spatial competition theory into such a framework, with the goal of motivating empirical investigations that adopt the comparative approach. The synthesis presented is based on a major axis, coexistence in spatially homogeneous vs. heterogeneous competitive environments, along which the theory can be organized. The resulting framework integrates such key concepts as niche theory, spatial heterogeneity and spatial scale(s) of coexistence. It yields comparative predictions that can guide empirical investigations.
Alternative prey can change model–mimic dynamics between parasitism and mutualism
Authors: Kokko Hanna , Mappes Johanna , Lindström Leena
Published: November 2003

Classical (conventional) Müllerian mimicry theory predicts that two (or more) defended prey sharing the same signal always benefit each other despite the fact that one species can be more toxic than the other. The quasi‐Batesian (unconventional) mimicry theory, instead, predicts that the less defended partner of the mimetic relationship may act as a parasite of the signal, causing a fitness loss to the model. Here we clarify the conditions for parasitic or mutualistic relationships between aposematic prey, and build a model to examine the hypothesis that the availability of alternative prey is crucial to Müllerian and quasi‐Batesian mimicry. Our model is based on optimal behaviour of the predator. We ask if and when it is in the interest of the predator to learn to avoid certain species as prey when there is alternative (cryptic) prey available. Our model clearly shows that the role of alternative prey must be taken into consideration when studying model–mimic dynamics. When food is scarce it pays for the predator to test the models and mimics, whereas if food is abundant predators should leave the mimics and models untouched even if the mimics are quite edible. Dynamics of the mimicry tend to be classically Müllerian if mimics are well defended, while quasi‐Batesian dynamics are more likely when they are relatively edible. However, there is significant overlap: in extreme cases mimics can be harmful to models (a quasi‐Batesian case) even if the species are equally toxic. A crucial parameter explaining this overlap is the search efficiency with which indiscriminating vs. discriminating predators find cryptic prey. Quasi‐Batesian mimicry becomes much more likely if discrimination increases the efficiency with which the specialized predator finds cryptic prey, while the opposite case tends to predict Müllerian mimicry. Our model shows that both mutualistic and parasitic relationship between model and mimic are possible and the availability of alternative prey can easily alter this relationship.
Explaining the coexistence of asexuals with their sexual progenitors: no evidence for general‐purpose genotypes in obligate parthenogens of the peach‐potato aphid, Myzus persicae
Authors: Vorburger Christoph , Sunnucks Paul , Ward Seamus A.
Published: November 2003

In parthenogens, selection acts on entire genotypes rather than individual alleles. The general‐purpose genotype hypothesis (GPG) predicts that temporally variable environments select for clones with broad ecological tolerances. These general‐purpose genotypes should exhibit low fitness variance and high geometric mean fitness across environments. We tested this hypothesis by comparing the fitness of obligately and cyclically parthenogenetic genotypes of the peach‐potato aphid, Myzus persicae, on three unrelated host plants. We found genetic variation for the relative performance on different hosts, but no difference in geometric mean fitness between obligate and cyclical parthenogens. Thus, for an environmental variable of major importance to aphids, the GPG hypothesis was not supported. In addition, the lack of an overall fitness difference between reproductive modes suggests that cyclical parthenogens incur no cost of polyphenism, but neither can they compensate for the cost of sex during the parthenogenetic phase of their life cycle.
When does parameter drift decrease the uncertainty in extinction risk estimates?
Authors: Ellner Stephen P.
Published: November 2003

Halley (2003) proposed that parameter drift decreases the uncertainty in long‐range extinction risk estimates, because drift mitigates the extreme sensitivity of estimated risk to estimated mean growth rate. However, parameter drift has a second, opposing effect: it increases the uncertainty in parameter estimates from a given data set. When both effects are taken into account, parameter drift can increase, sometimes substantially, the uncertainty in risk estimates. The net effect depends sensitively on the type of drift and on which model parameters must be estimated from observational data on the population at risk. In general, unless many parameters are estimated from independent data, parameter drift increases the uncertainty in extinction risk. These findings suggest that more mechanistic PVA models, using long‐term data on key environmental variables and experiments to quantify their demographic impacts, offer the best prospects for escaping the high data requirements when extinction risk is estimated from observational data.
Patterns of functional diversity across an extensive environmental gradient: vertebrate consumers, hidden treatments and latitudinal trends
Authors: Stevens Richard D. , Cox Stephen B. , Strauss Richard E. , Willig Michael R.
Published: November 2003

Over the last two decades, although much has been learned regarding the multifaceted nature of biodiversity, relatively little is known regarding spatial variation in constituents other than species richness. This is particularly true along extensive environmental gradients such as latitude. Herein, we describe latitudinal gradients in the functional diversity of New World bat communities. Bat species from each of 32 communities were assigned to one of seven functional groups. Latitudinal gradients existed for the richness, diversity and scaled‐dominance of functional groups. No significant patterns were observed for evenness of functional groups. Measures of functional diversity were different in magnitude and increased towards the equator at a faster rate than expected given the underlying spatial variation in species richness. Thus, latitudinal gradient in species richness alone do not cause the latitudinal gradient in functional diversity. When variation in species composition of the regional fauna of each community was incorporated into analyses, many differences between observed and simulated patterns of functional diversity were not significant. This suggests that those processes that determine the composition of regional faunas strongly influence the latitudinal gradient in functional diversity at the local level. Nonetheless, functional diversity was lower than expected across observed sites. Community‐wide responses to variation in the quantity and quality of resources at the local level probably contribute to differences in functional diversity at local and regional scales and enhance beta diversity.
Rates of spread of marine pathogens
Authors: McCallum Hamish , Harvell Drew , Dobson Andy
Published: November 2003

Epidemics of marine pathogens can spread at extremely rapid rates. For example, herpes virus spread through pilchard populations in Australia at a rate in excess of 10 000 km year−1, and morbillivirus infections in seals and dolphins have spread at more than 3000 km year−1. In terrestrial environments, only the epidemics of myxomatosis and calicivirus in Australian rabbits and West Nile Virus in birds in North America have rates of spread in excess of 1000 km year−1. The rapid rates of spread of these epidemics has been attributed to flying insect vectors, but flying vectors have not been proposed for any marine pathogen. The most likely explanation for the relatively rapid spread of marine pathogens is the lack of barriers to dispersal in some parts of the ocean, and the potential for long‐term survival of pathogens outside the host. These findings caution that pathogens may pose a particularly severe problem in the ocean. There is a need to develop epidemic models capable of generating these high rates of spread and obtain more estimates of disease spread rate.
A Review of Cross‐border Mergers and Acquisitions in APEC
Authors: Chen Chunlai , Findlay Christopher
Published: November 2003

In parallel with global trends, cross‐border mergers and acquisitions (M&As) have increased dramatically in the APEC economies especially since the mid 1990s. The rapid increase in cross‐border M&As in the world in general and in the APEC economies in particular is driven by a combination of factors, including the liberalisation of trade and investment regimes, the deregulation of the services sector, the privatisation of state‐owned enterprises, and the relaxation of controls over cross‐border M&As. The role of APEC developing economies in cross‐border M&As has been increasing, especially since the late 1990s.
Globalisation and Consumer Protection in East Asia: is it a zero sum game?
Authors: Round David K. , Sporer Zeljka
Published: November 2003

The provision of comprehensive consumer protection legislation is not high on the policy agenda in most developing economies, given what are seen to be more urgent economic and social goals such as encouraging economic growth and the eradication of poverty and illiteracy. Yet large welfare losses can occur as a result of market failure due to the significant information asymmetries that usually exist in developing economies, with buyers being at the mercy of much better informed sellers. It is time to overcome this problem through education, legislation and the creation of appropriate bureaucratic institutions. However, through globalisation the market itself may be able to achieve a greater degree of consumer protection, certainly in the short term, than would otherwise be achieved in the absence of such forces. While globalisation may create problems, it provides an opportunity to solve some consumer protection problems—a benefit from globalisation not previously highlighted. This article suggests that the nations of East Asia seek a regional consensus on developing a culture for consumer protection and on the implementation of consumer protection laws and enforcement procedures.
Treatment of Primary Headache in the Emergency Department
Authors: Blumenthal Harvey J. , Weisz Michael A. , Kelly Karen M. , Mayer Renae L , Blonsky Jeffrey
Published: November 2003

Background.—Each year many patients present to an emergency department for treatment of acute primary headache. We investigated the diagnosis and clinical outcome of patients treated for primary headache in the emergency department.

Methods.—Patients treated for acute primary headache in the emergency department completed a questionnaire related to their headache symptoms, response to treatment, and ability to return to normal function. These responses were compared to the treating physicians' observations of the patient's condition at the time of discharge from the emergency department.

Results.—Based on the questionnaire, 95% of the 57 respondents met International Headache Society diagnostic criteria for migraine. Emergency department physicians, however, diagnosed only 32% of the respondents with migraine, while 59% were diagnosed as having “cephalgia” or “headache NOS” (not otherwise specified). All patients previously had taken nonprescription medication, and 49% had never taken a triptan. In the emergency department, only 7% of the patients received a drug “specific” for migraine (ie, a triptan or dihydroergotamine). Sixty‐five percent of the patients were treated with a “migraine cocktail” comprised of a variable mixture of a nonsteroidal anti‐inflammatory agent, a dopamine antagonist, and/or an antihistamine; 24% were treated with opioids. All 57 patients reported that after discharge they had to rest or sleep and were unable to return to normal function. Sixty percent of patients still had headache 24 hours after discharge from the emergency department.

Conclusion.—The overwhelming majority of patients who present to an emergency department with acute primary headache have migraine, but the majority of patients receive a less specific diagnosis and a treatment that is correspondingly nonspecific.
Exploring the Relationship Between Maternal Migraine and Child Functioning
Authors: Fagan Maria A.
Published: November 2003

Objective.—To investigate the relationship between mothers' migraines and the roles and expectations of their children.

Methods.—Twenty‐five mothers diagnosed with migraine completed questionnaires concerning their levels of migraine‐related disability and their parenting and child‐rearing attitudes. Migraine‐related disability was assessed using the Migraine‐Specific Quality of Life Questionnaire (version 2.1). Parenting and child‐rearing attitudes were assessed using the Adult‐Adolescent Parenting Inventory.

Results.—Significant positive relationships were found between the mothers' migraine‐related disability and both inappropriate expectations of their children and parent‐child role reversal; ie, the more migraine‐related disability reported by the mothers, the more they reported having inappropriate expectations of their children and favoring parent‐child role reversal.

Conclusions.—This study suggests that migraine may be associated with dysfunctional parenting patterns. More specifically, it suggests that in families wherein the mother has migraine, children may be at risk of inappropriately or prematurely assuming roles for which they are developmentally unready. Clinical implications are that mothers with migraine may benefit from some type of family‐focused intervention, in addition to headache treatment.
Atypical Odontalgia: A Review of the Literature
Authors: Melis Marcello , Lobo Silvia Lobo , Ceneviz Caroline , Zawawi Khalid , Al‐Badawi Emad , Maloney George , Mehta Noshir
Published: November 2003

Objective.—To review previous reports of cases of atypical odontalgia to examine its epidemiological and clinical characteristics and to explore the etiology and pathophysiology of the disease.

Background.—Atypical odontalgia is one of many painful conditions that affect the oral cavity and is often overlooked in the differential diagnosis.

Methods.—A search of the literature was performed for all cases of atypical odontalgia reported from 1966 to the present.

Results.—The typical clinical presentation of atypical odontalgia that has been reported involves pain in a tooth in the absence of any sign of pathology; the pain may spread to areas of the face, neck, and shoulder. The existing literature suggests that this condition occurs in 3% to 6% of the patients who undergo endodontic treatment, with high female preponderance and a concentration of cases in the fourth decade of life. Deafferentation seems to be the most likely mechanism to initiate the pain, but psychological factors, alteration of neural mechanisms, and even an idiopathic mechanism have been implicated. Not all reported cases were preceded by trauma to the teeth or gums.

The treatment of choice is a tricyclic antidepressant, alone or in combination with a phenothiazine. The outcome is usually fair, with many patients obtaining complete relief from pain. Especially in the absence of overt pathology, particular attention should be paid to avoiding any unnecessary and potentially dangerous dental intervention on the teeth.

Conclusion.—Atypical odontalgia is surprisingly common, of uncertain origin, and potentially treatable.
Early Intervention With Almotriptan Improves Sustained Pain‐free Response in Acute Migraine
Authors: Mathew Ninan T.
Published: November 2003

Objective.—To determine whether treatment of migraine with almotriptan, when pain intensity is mild, improves 1‐ and 2‐hour pain‐free and sustained pain‐free rates compared with treatment when pain intensity is moderate or severe.

Methods.—This was a post hoc analysis derived from an open‐label, multicenter, long‐term study of the safety, tolerability, and efficacy of almotriptan 12.5 mg. Patients who met International Headache Society criteria for migraine with or without aura were eligible. Patients were instructed to take a single dose of almotriptan 12.5 mg at the onset of a migraine attack. Rescue medication could be taken if migraine pain had not disappeared at 2 hours. A second dose of almotriptan 12.5 mg could be taken if head pain recurred within 24 hours of the initial dose. Patients reported the intensity of pain at baseline and at 1 and 2 hours postmedication using a 4‐point scale: no pain, mild, moderate, or severe pain. They also reported recurrence of pain (return of moderate or severe pain within 2 to 24 hours of taking the study medication) and use of rescue medication. Rescue medication consisted of supplemental analgesics taken for pain relief at 2 to 24 hours postdose. Ergotamines and other 5‐HT1B/1D agonists were excluded as rescue medications. Based on these patient‐reported end points, sustained pain‐free rates, defined as pain‐free at 2 hours with no recurrence from 2 to 24 hours and no use of rescue medication, were calculated.

Results.—A higher proportion of migraine attacks of mild intensity were pain‐free at 1 hour (35.3%) compared with attacks of moderate or severe intensity (7.5%) (P < .001). Two‐hour pain‐free rates also were significantly higher with mild intensity pain (76.9%) compared to moderate or severe intensity (43.9%) (P < .001). In addition, recurrence rates and use of rescue medication were reduced when attacks were treated during mild pain. Recurrence was 12.9% for mild pain versus 25.0% for moderate or severe pain (P < .001), and use of rescue medication was 9.4% for mild pain versus 17.2% for moderate or severe pain (P < .001). Sustained pain‐free rates were nearly twice as high when attacks were treated during mild intensity pain (66.6%) compared with attacks treated during moderate or severe pain (36.6%) (P < .001).

Conclusion.—Treatment with almotriptan 12.5 mg during migraine attacks of mild pain intensity improves 1‐ and 2‐hour pain‐free and sustained pain‐free responses.