bluuebunny/crossref_metadata_2025 huggingface dataset:
Spontaneous Intracranial Hypotension with Isolated Cortical Vein Thrombosis and Subarachnoid Haemorrhage
Authors: Wang Y-F , Fuh J-L , Lirng J-F , Chang F-C , Wang S-J
Published: September 2007

Spontaneous intracranial hypotension (SIH) associated with subarachnoid haemorrhage (SAH) has never been reported. Here, we report on a case of a 33-year-old woman with SIH, who developed simple partial sensory seizures 3 weeks later. Neuroimaging studies, including brain computed tomography and angiography, were initially normal, but revealed an isolated cortical venous thrombosis at 3 weeks. One week later, brain magnetic resonance imaging showed SAH around the thrombosed cortical vein. We postulate that the decline in the venous blood flow velocity due to SIH may have resulted in cortical venous thrombosis, which in turn led to rupture of the vessel wall and SAH in this patient.
Characteristics of Neck Pain Associated With Adolescent Headache
Authors: Laimi K , Salminen JJ , Metsähonkala L , Vahlberg T , Mikkelsson M , Anttila P , Aromaa M , Rautava P , Suominen S , Liljeström M-R , Sillanpää M
Published: September 2007

The objective of the study was to find out what kind of neck pain (NP) is associated with headache (HA) and with various headache variables: frequency, type, intensity, disturbance, and relief with analgesics. A population-based sample of 12-year-olds with and without HA ( n = 304) was followed for 4 years. At the age of 16 years, NP was evaluated on the basis of self-reported symptoms and a thorough physical examination of the neck region. Both self-reported and measured NP were associated with HA variables. Co-occurrent NP was found in adolescents with migraine as often as in those with tension-type HA. Especially, muscle pain and intensive, frequent NP were associated with disturbing HA unresponsive to analgesics. The study indicates that concomitant NP should be considered in adolescent HA sufferers, and a thorough cervical and muscle evaluation is recommended when planning the treatment of HA.
Ethanol Causes Neurogenic Vasodilation by TRPV1 Activation and CGRP Release in the Trigeminovascular System of The Guinea Pig
Authors: Nicoletti P , Trevisani M , Manconi M , Gatti R , Siena G De , Zagli G , Benemei S , Capone JA , Geppetti P , Pini LA
Published: September 2007

Ethanol stimulating transient receptor potential vanilloid 1 (TRPV1) on primary sensory neurons promotes neurogenic inflammation, including calcitonin gene-related peptide (CGRP)-mediated coronary dilation. Alcoholic beverages trigger migraine attacks and activation of trigeminal neurons plays a role in migraine. We have investigated in guinea pigs whether ethanol by TRPV1 stimulation causes neurogenic inflammation in the trigeminovascular system. Ethanolevoked release of neuropeptides from slices of dura mater was abolished by Ca2+removal, capsaicin pretreatment and the TRPV1 antagonist, capsazepine. Intragastric ethanol increased plasma extravasation in dura mater, an effect abolished by capsazepine and the NK1 receptor antagonist, SR140333, and caused vasodilation around the middle meningeal artery, an effect abolished by capsazepine and the CGRP receptor antagonist, BIBN4096BS. Vasodilation of meningeal vessels by TRPV1 activation and CGRP release may be relevant to the mechanism by which alcohol ingestion triggers migraine attacks.
Comorbidity of Migraine and Restless Legs Syndrome—A Case-Control Study
Authors: Rhode AM , Hösing VG , Happe S , Biehl K , Young P , Evers S
Published: September 2007

In order to evaluate a possible association between migraine and restless legs syndrome (RLS), we performed a case-control study on the comorbidity of RLS and migraine. Patients with migraine ( n = 411) and 411 sex- and age-matched control subjects were included. Migraine was diagnosed according to International Headache Society criteria, RLS according to the criteria of the International Restless Legs Syndrome Study Group. Furthermore, all patients had to fill out a self-assessment test performance on depression [Beck's Depression Inventory (BDI)]. RLS frequency was significantly higher in migraine patients than in control subjects (17.3% vs. 5.6%, P < 0.001; odds ratio 3.5, confidence interval 2.2, 5.8). In our sample, there was no significant association between migraine and depression as defined by the BDI score (9.6% in migraine vs. 4.0% in control subjects, P = 0.190). Depression was, however, not significantly more frequent in migraine patients with RLS (13.6%) than in migraine patients without RLS (8.7%). In addition, migraine patients with RLS had a significantly higher BDI score. RLS features did not differ significantly between migraine patients with RLS and control subjects with RLS. There is an association between RLS and migraine and, in addition, a co-association with depression. The underlying mechanism, however, remains undetermined and might be related to a dysfunction of dopaminergic metabolism in migraine.
Pregabalin effectiveness and tolerability in the prophylactic treatment of chronic migraine
Authors: Calandre Elena P. , Garcia-Leiva Juan M. , Rodriguez-Lopez Carmen M. , Rico-Villademoros Fernando
Published: September 2007

Objectives

To evaluate the effectiveness and tolerability of pregabalin in the prophylaxis of chronic migraine.

Methods

17 patients (11 women, 6 men), 25 to 69 years, diagnosed of chronic migraine according to IHS criteria, and most of them (88%) refractory to previous prophylactic drug therapies, received pregabalin during 12 weeks in a starting dose of 75 mg/day subsequently adjusted according to patients' clinical response. The main outcome measure was the decrease in attacks' frequency. Secondary outcome measures included changes in attacks' severity and in the Headache Impact Test (HIT-6) score. Emergent adverse reactions to drug were recorded.

Results

Pregabalin final dose ranged from 150 to 450 mg/day (303 ± 118). Monthly attacks = frequency decreased from 22.5 ± 5.8 to 18.5 ± 9.9 (P < 0.0001; Effect Size [ES]:0.69). The frequency of attacks of severe intensity decreased from 7.8 ± 6.3 to 4.6 ± 6.0 (P = 0.0042; ES:0.51) without relevant changes in the frequency of moderate and mild intensity attacks. HIT-6 scores decreased from 64.4 ± 5.8 to 55.5 ± 11.7 (P = 0.0002; ES:1,53). Eight cases of pregabalin-associated adverse reactions were reported: four cases of dizziness and four of sedation. Two patients withdraw the study due to side effects.

Conclusions

Pregabalin was effective and well tolerated in this sample of predominantly refractory chronic migraine, reducing markedly both the frequency and severity of attacks, and decreasing significantly the impact of their disease on daily activities. Controlled studies evaluating the efficacy of this drug in migraine prophylaxis seem warranted.
Food on Film: Pilot Test of an Innovative Method for Recording Food Intake of Adults with Intellectual Disabilities Living in the Community
Authors: Humphries Kathleen , Traci Meg Ann , Seekins Tom
Published: September 2007

Background Adults with intellectual or developmental disabilities need dietary monitoring but are not likely to be able to provide accurate dietary intake data via traditional methods. Pilot study efforts to meet their support needs with a novel and practical approach to dietary intake data collection are described in this brief report.

Materials and Method Still photography kits were used by nine adult volunteer participants with intellectual disabilities who lived in group homes or in semi‐independent living arrangements to capture images of the food they consumed over 24 h.

Results Use of photographs during dietary intake interviews improved the reliability of the participants’ responses. Mean reliability ratings improved from ‘Indiscernible/Poor’ (mean range 1.0–1.7) to ‘Good/Excellent’ (mean range 3.6–5.0).

Conclusions Our preliminary data imply thatFood on Filmis an effective and appropriate tool for use in community settings and warrants further testing.
Care Standards in Homes for People with Intellectual Disabilities
Authors: Beadle‐Brown Julie , Hutchinson Aislinn , Mansell Jim
Published: September 2007

Background  National minimum standards for residential care homes were introduced following the Care Standards Act 2000 in response to concern about the lack of consistency and poor quality services. These standards are intended to reflect outcomes for service users and to be comprehensive in scope.

Method  This study compared ratings made by care standards inspectors with research measures for 52 homes for people with intellectual disabilities serving 299 people. The research measures focused on the lived experience of residential care, including engagement in meaningful activity, choice and participation in activities of daily living. They also included measures of related care practices and organizational arrangements.

Results  The research measures were in general significantly correlated with each other. Most of the care standards ratings were also correlated with each other. However, only two of 108 correlations between care standards and research measures were significant. Possible reasons for this are discussed.

Conclusions  This study confirms that the review of national minimum standards and modernization of inspection methods recently announced by the Department of Health and the Commission for Social Care Inspection are timely and appropriate.
The rare Lutheran blood group phenotype Lu(a–b–): a genetic study
Authors: SHAW M. A. , LEAK M. R. , DANIELS G. L. , TIPPETT P.
Published: September 2007

The rare blood group phenotype lacking Lutheran antigens, Lu(a–b–), is known to have two genetic backgrounds. Tests on 250000 blood donors show the frequency of Lu(a–b–) to be approximately 1 in 3000. The families of 41 propositi show the dominant inhibitor of Lutheran antigens, In(Lu), to be the usual cause of the phenotype in South East England; there was no proven case of the recessive background, LuLu. Lod scores for In(Lu) and other blood group loci are presented; the only hint of linkage is between In(Lu) and Rh. The suppressing effect of In(Lu) on the expression of antigens of unrelated blood group systems, P1, Aua and i, is confirmed.
The anuran Bauplan: a review of the adaptive, developmental, and genetic underpinnings of frog and tadpole morphology
Authors: Handrigan Gregory R. , Wassersug Richard J.
Published: September 2007

Anurans (frogs, toads, and their larvae) are among the most morphologically derived of vertebrates. While tightly conserved across the order, the anuran Bauplan (body plan) diverges widely from that of other vertebrates, particularly with respect to the skeleton. Here we address the adaptive, ontogenetic, and genetic bases of three such hallmark anuran features: (1) the absence of discrete caudal vertebrae, (2) a truncated axial skeleton, and (3) elongate hind limbs. We review the functional significance of each as it relates to the ans uran lifestyle, which includes locomotor adaptations to both aquatic and terrestrial environments. We then shift our focus to the proximal origins of each feature, namely, ontogeny and its molecular regulation. Drawing on relatively limited data, we detail the development of each character and then, by extrapolating from comparative vertebrate data, propose molecular bases for these processes. Cast in this light, the divergent morphology of anurans emerges as a product of evolutionary modulation of the generalised vertebrate developmental machinery. Specifically, we hypothesise that: (1) the formation of caudal vertebrae is precluded due to a failure of sclerotomes to form cartilaginous condensations, perhaps resulting from altered expression of a suite of genes, including Pax1, Pax9, Msx1, Uncx‐4.1, Sonic hedgehog, and noggin; (2) anteriorised Hox gene expression in the paraxial mesoderm has led to a rostral shift of morphological boundaries of the vertebral column; and, (3) spatial and temporal shifts in Hox expression may underlie the expanded tarsal elements of the anuran hind limb. Technology is currently in place to investigate each of these scenarios in the African clawed frog Xenopus. Experimental corroboration will further our understanding of the molecular regulation of the anuran Bauplan and provide insight into the origin of vertebrate morphological diversity as well as the role of development in evolution.
Spider sex pheromones: emission, reception, structures, and functions
Authors: Gaskett A. C.
Published: September 2007

Spiders and their mating systems are useful study subjects with which to investigate questions of widespread interest about sexual selection, pre‐ and post‐copulatory mate choice, sperm competition, mating strategies, and sexual conflict. Conclusions drawn from such studies are broadly applicable to a range of taxa, but rely on accurate understanding of spider sexual interactions. Extensive behavioural experimentation demonstrates the presence of sex pheromones in many spider species, and recent major advances in the identification of spider sex pheromones merit review. Synthesised here are the emission, transmission, structures, and functions of spider sex pheromones, with emphasis on the crucial and dynamic role of sex pheromones in female and male mating strategies generally. Techniques for behavioural, chemical and electrophysiological study are summarised, and I aim to provide guidelines for incorporating sex pheromones into future studies of spider mating.

In the spiders, pheromones are generally emitted by females and received by males, but this pattern is not universal. Female spiders emit cuticular and/or silk‐based sex pheromones, which can be airborne or receivedviacontact with chemoreceptors on male pedipalps. Airborne pheromones primarily attract males or elicit male searching behaviour. Contact pheromones stimulate male courtship behaviour and provide specific information about the emitter’s identity. Male spiders are generally choosy and are often most attracted to adult virgin females and juvenile females prior to their final moult. This suggests the first male to mate with a female has significant advantages, perhaps due to sperm priority patterns, or mated female disinterest. Both sexes may attempt to control female pheromone emission, and thus dictate the frequency and timing of female mating, reflecting the potentially different costs of female signalling and/or polyandry to both sexes. Spider sex pheromones are likely to be lipids or lipid soluble, may be closely related to primary metabolites, and are not necessarily species specific, although they can still assist with species recognition. Newer electrophysiological techniques coupled with chemical analyses assist with the identification of sex pheromone compounds. This provides opportunities for more targeted behavioural experimentation, perhaps with synthetic pheromones, and for theorising about the biosynthesis and evolution of chemical signals generally. Given the intriguing biology of spiders, and the critical role of chemical signals for spiders and many other animal taxa, a deeper understanding of spider sex pheromones should prove productive.
Amphibian teeth: current knowledge, unanswered questions, and some directions for future research
Authors: Davit‐Béal Tiphaine , Chisaka Hideki , Delgado Sidney , Sire Jean‐Yves
Published: September 2007

Elucidation of the mechanisms controlling early development and organogenesis is currently progressing in several model species and a new field of research, evolutionary developmental biology, which integrates developmental and comparative approaches, has emerged. Although the expression pattern of many genes during tooth development in mammals is known, data on other lineages are virtually non‐existent. Comparison of tooth development, and particularly of gene expression (and function) during tooth morphogenesis and differentiation, in representative species of various vertebrate lineages is a prerequisite to understand what makes one tooth different from another. Amphibians appear to be good candidates for such research for several reasons: tooth structure is similar to that in mammals, teeth are renewed continuously during life ( = polyphyodonty), some species are easy to breed in the laboratory, and a large amount of morphological data are already available on diverse aspects of tooth biology in various species. The aim of this review is to evaluate current knowledge on amphibian teeth, principally concerning tooth development and replacement (including resorption), and changes in morphology and structure during ontogeny and metamorphosis. Throughout this review we highlight important questions which remain to be answered and that could be addressed using comparative morphological studies and molecular techniques. We illustrate several aspects of amphibian tooth biology using data obtained for the caudate Pleurodeles waltl. This salamander has been used extensively in experimental embryology research during the past century and appears to be one of the most favourable amphibian species to use as a model in studies of tooth development.
Coloured nectar: distribution, ecology, and evolution of an enigmatic floral trait
Authors: Hansen Dennis M. , Olesen Jens M. , Mione Thomas , Johnson Steven D. , Müller Christine B.
Published: September 2007

While coloured nectar has been known to science at least since 1785, it has only recently received focused scientific attention. However, information about this rare floral trait is scattered and hard to find. Here, we document coloured nectar in 67 taxa worldwide, with a wide taxonomical and geographical distribution. We summarise what is currently known about coloured nectar in each of the lineages where it occurs. The most common nectar colours are in the spectrum from yellow to red, but also brown, black, green, and blue colours are found. Colour intensity of the nectar varies, sometimes even within one taxa, as does the level of contrast between flower petals and nectar. Coloured nectar has evolved independently throughout the angiosperms at least 15 times at the level of family, and is in many cases correlated with one or more of three parameters: (1) vertebrate pollination, known or hypothesised, (2) insularity – many species are from islands or insular mainland habitats, and (3) altitude – many species are found at relatively high altitudes. We discuss the evolution and speculate on possible ecological functions of coloured nectar. Apart from being a non‐functional, perhaps pleiotropic, trait, we present several hypotheses on possible ecological functions of coloured nectar. Firstly, for some plant species it can be interpreted as an honest signal, leading to high pollination efficiency. Secondly, it can function as a deterrent against nectar‐thieves or inefficient pollinators, thus acting as a floral filter. Thirdly, nectar colour‐pigments can have anti‐microbial qualities that may protect the nectar in long‐lived flowers. Neither of these possibilities are mutually exclusive. Recent studies have provided experimental evidence for the first two hypotheses, and we suggest promising avenues for future research into this little‐known floral trait.
Quantitative steps in the evolution of metabolic organisation as specified by the Dynamic Energy Budget theory
Authors: Kooijman S. A. L. M. , Troost T. A.
Published: September 2007

The Dynamic Energy Budget (DEB) theory quantifies the metabolic organisation of organisms on the basis of mechanistically inspired assumptions. We here sketch a scenario for how its various modules, such as maintenance, storage dynamics, development, differentiation and life stages could have evolved since the beginning of life. We argue that the combination of homeostasis and maintenance induced the development of reserves and that subsequent increases in the maintenance costs came with increases of the reserve capacity. Life evolved from a multiple reserves ‐ single structure system (prokaryotes, many protoctists) to systems with multiple reserves and two structures (plants) or single reserve and single structure (animals). This had profound consequences for the possible effects of temperature on rates. We present an alternative explanation for what became known as the down‐regulation of maintenance at high growth rates in microorganisms; the density of the limiting reserve increases with the growth rate, and reserves do not require maintenance while structure‐specific maintenance costs are independent of the growth rate. This is also the mechanism behind the variation of the respiration rate with body size among species. The DEB theory specifies reserve dynamics on the basis of the requirements of weak homeostasis and partitionability. We here present a new and simple mechanism for this dynamics which accounts for the rejection of mobilised reserve by busy maintenance/growth machinery. This module, like quite a few other modules of DEB theory, uses the theory of Synthesising Units; we review recent progress in this field. The plasticity of membranes that evolved in early eukaryotes is a major step forward in metabolic evolution; we discuss quantitative aspects of the efficiency of phagocytosis relative to the excretion of digestive enzymes to illustrate its importance. Some processes of adaptation and gene expression can be understood in terms of allocation linked to the relative workload of metabolic modules in (unicellular) prokaryotes and organs in (multicellular) eukaryotes. We argue that the evolution of demand systems can only be understood in the light of that of supply systems. We illustrate some important points with data from the literature.
Parasite recruitment and oceanographic regime: evidence suggesting a relationship on a global scale
Authors: Pascual Santiago , González Ángel F. , Guerra Ángel
Published: September 2007

We here investigate the relationship between oceanographic processes and variability in parasite recruitment to host populations using existing data from host‐parasite systems encountering differing hydrographic conditions. Combined epidemiological data obtained from both exploited fish and cephalopod populations indicate that variability in recruitment of parasite infracommunities tends to be associated with major current systems of the World’s oceans. It appears that instability in water masses caused by physical perturbations (e.g. water mass convergence and turbulent mixing in upwelling systems) is associated with instability of trophic interactions over time, which in turn leads to a paucity of parasite communities in that area. The likely relationship between parasite recruitment and oceanographic regime should be extremely useful to the fishing industry and also as an indicator of ecosystem health.
The role of chemical communication in mate choice
Authors: Johansson Björn G. , Jones Therésa M.
Published: September 2007

Chemical signals are omnipresent in sexual communication in the vast majority of living organisms. The traditional paradigm was that their main purpose in sexual behaviour was to coordinate mate and species recognition and thus pheromones were conserved in structure and function. In recent years, this view has been challenged by theoretical analyses on the evolution of pheromones and empirical reports of mate choice based on chemical signals. The ability to measure precisely the quantity and quality of chemicals emitted by single individuals has also revealed considerable individual variation in chemical composition and release rates, and there is mounting evidence that prospecting mates respond to this variation. Here, we review the evidence for pheromones as indicators of mate quality and examine the extent of their use in individual mate assessment. We begin by briefly defining the levels of mate choice – species recognition, mate recognition and mate assessment. We then explore the degree to which pheromones satisfy the key criteria necessary for their evolution and maintenance as cues in mate assessment; that is, they should exhibit variation across individuals within a sex and species; they should honestly reflect an individual’s quality and thus be costly to produce and/or maintain; they should display relatively high levels of heritability. There is now substantial empirical evidence that pheromones can satisfy all these criteria and, while measurements of the actual metabolic cost of pheromone production remain to some degree lacking, trade‐offs between pheromone production and various fitness‐related characters such as growth rate, immunocompetence and longevity have been reported for a range of species. In the penultimate section, we outline the growing number of studies where the consequences of chemical‐based mate assessment have been investigated, specifically focussing on the reported direct and genetic benefits accrued by the receiver. Finally, we highlight potential areas for future research and in particular emphasise the need for interdisciplinary research that combines exploration of chemical, physiological and behavioural processes to further our understanding of the role of chemical cues in mate assessment.
Integrating animal temperament within ecology and evolution
Authors: Réale Denis , Reader Simon M. , Sol Daniel , McDougall Peter T. , Dingemanse Niels J.
Published: September 2007

Temperament describes the idea that individual behavioural differences are repeatable over time and across situations. This common phenomenon covers numerous traits, such as aggressiveness, avoidance of novelty, willingness to take risks, exploration, and sociality. The study of temperament is central to animal psychology, behavioural genetics, pharmacology, and animal husbandry, but relatively few studies have examined the ecology and evolution of temperament traits. This situation is surprising, given that temperament is likely to exert an important influence on many aspects of animal ecology and evolution, and that individual variation in temperament appears to be pervasive amongst animal species. Possible explanations for this neglect of temperament include a perceived irrelevance, an insufficient understanding of the link between temperament traits and fitness, and a lack of coherence in terminology with similar traits often given different names, or different traits given the same name. We propose that temperament can and should be studied within an evolutionary ecology framework and provide a terminology that could be used as a working tool for ecological studies of temperament. Our terminology includes five major temperament trait categories: shyness‐boldness, exploration‐avoidance, activity, sociability and aggressiveness. This terminology does not make inferences regarding underlying dispositions or psychological processes, which may have restrained ecologists and evolutionary biologists from working on these traits. We present extensive literature reviews that demonstrate that temperament traits are heritable, and linked to fitness and to several other traits of importance to ecology and evolution. Furthermore, we describe ecologically relevant measurement methods and point to several ecological and evolutionary topics that would benefit from considering temperament, such as phenotypic plasticity, conservation biology, population sampling, and invasion biology.
Paternal kin discrimination: the evidence and likely mechanisms
Authors: Widdig Anja
Published: September 2007

One of the most important assumptions of kin selection theory is that individuals behave differently towards kin than non‐kin. In mammals, there is strong evidence that maternal kin are distinguished from non‐kinviafamiliarity. However, little is known about whether or not mammals can also recognize paternal kin as many female mammals, including primates, mate with multiple males near the time of conception, potentially concealing paternal kinship. Genetic data in several mammalian species with a promiscuous mating system and male‐biased dispersal reveal a high skew in male reproduction which leads to co‐residing paternal half‐siblings. In most primates, individuals also form stable bisexual groups creating opportunities for males to interact with their offspring. Here I consider close paternal kin co‐resident in the same social group, such as father‐offspring and paternal half‐siblings (i.e. animals sharing the same father but who were born to different mothers) and review mammalian studies of paternal kin discrimination. Furthermore, I summarize the most likely mechanisms of paternal kin discrimination (familiarity and phenotype matching). When familiarity is the underlying mechanism, mothers and/or the sire could mediate familiarity among paternal half‐siblings as well as between fathers and offspring assuming mothers and/or fathers can assess paternity. When animals use phenotype matching, they might use their fathers’ template (when the father is present) or self (when the father is absent) to assess paternal kinship in others. Available evidence suggests that familiarity and phenotype matching might be used for paternal kin discrimination and that both mechanisms might apply to a wide range of social mammals characterized by a high skew in male reproduction and co‐residence of paternal kin. Among primates, suggested evidence for phenotype matching can often have an alternative explanation, which emphasizes the crucial importance of controlling for familiarity as a potential confounding variable. However, the mechanism/s used to identify paternal kin might differ within a species (as a function of each individual’s specific circumstances) as well as among species (depending upon the key sensory modalities of the species considered). Finally, I discuss the possible cues used in paternal kin discrimination and offer suggestions for future studies.
Petroleum hydrocarbon contamination in boreal forest soils: a mycorrhizal ecosystems perspective
Authors: Robertson Susan J. , McGill William B. , Massicotte Hugues B. , Rutherford P. Michael
Published: September 2007

The importance of developing multi‐disciplinary approaches to solving problems relating to anthropogenic pollution is now clearly appreciated by the scientific community, and this is especially evident in boreal ecosystems exposed to escalating threats of petroleum hydrocarbon (PHC) contamination through expanded natural resource extraction activities. This review aims to synthesize information regarding the fate and behaviour of PHCs in boreal forest soils in both ecological and sustainable management contexts. From this, we hope to evaluate potential management strategies, identify gaps in knowledge and guide future research. Our central premise is that mycorrhizal systems, the ubiquitous root symbiotic fungi and associated food‐web communities, occupy the structural and functional interface between decomposition and primary production in northern forest ecosystems (i.e. underpin survival and productivity of the ecosystem as a whole), and, as such, are an appropriate focal point for such a synthesis. We provide pertinent basic information about mycorrhizas, followed by insights into the ecology of ecto‐ and ericoid mycorrhizal systems. Next, we review the fate and behaviour of PHCs in forest soils, with an emphasis on interactions with mycorrhizal fungi and associated bacteria. Finally, we summarize implications for ecosystem management. Although we have gained tremendous insights into understanding linkages between ecosystem functions and the various aspects of mycorrhizal diversity, very little is known regarding rhizosphere communities in PHC‐contaminated soils. This makes it difficult to translate ecological knowledge into environmental management strategies. Further research is required to determine which fungal symbionts are likely to survive and compete in various ecosystems, whether certain fungal ‐ plant associations gain in ecological importance following contamination events, and how PHC contamination may interfere with processes of nutrient acquisition and exchange and metabolic processes. Research is also needed to assess whether the metabolic capacity for intrinsic decomposition exists in these ecosystems, taking into account ecological variables such as presence of other organisms (and their involvement in syntrophic biodegradation), bioavailability and toxicity of mixtures of PHCs, and physical changes to the soil environment.
Ecological correlates of body size in relation to cell size and cell number: patterns in flies, fish, fruits and foliage
Authors: Arendt Jeff
Published: September 2007

Body size is important to most aspects of biology and is also one of the most labile traits. Despite its importance we know remarkably little about the proximate (developmental) factors that determine body size under different circumstances. Here, I review what is known about how cell size and number contribute to phenetic and genetic variation in body size inDrosophila melanogaster, several fish, and fruits and leaves of some angiosperms. Variation in resources influences size primarily through changes in cell number while temperature acts through cell size. The difference in cellular mechanism may also explain the differences in growth trajectories resulting from food and temperature manipulations. There is, however, a poorly recognized interaction between food and temperature effects that needs further study. In addition, flies show a sexual dimorphism in temperature effects with the larger sex responding by changes in cell size and the smaller sex showing changes in both cell size and number. Leaf size is more variable than other organs, but there appears to be a consistent difference between how shade‐tolerant and shade‐intolerant species respond to light level. The former have larger leavesviacell size under shade, the latterviacell number in light conditions. Genetic differences, primarily from comparisons ofD. melanogaster, show similar variation. Direct selection on body size alters cell number only, while temperature selection results in increased cell size and decreased cell number. Population comparisons along latitudinal clines show that larger flies have both larger cells and more cells. Use of these proximate patterns can give clues as to how selection acts in the wild. For example, the latitudinal pattern inD. melanogasteris usually assumed to be due to temperature, but the cellular pattern does not match that seen in laboratory selection at different temperatures.
Use, misuse and extensions of “ideal gas” models of animal encounter
Authors: Hutchinson John M. C. , Waser Peter M.
Published: September 2007

Biologists have repeatedly rediscovered classical models from physics predicting collision rates in an ideal gas. These models, and their two‐dimensional analogues, have been used to predict rates and durations of encounters among animals or social groups that move randomly and independently, given population density, velocity, and distance at which an encounter occurs. They have helped to separate cases of mixed‐species association based on behavioural attraction from those that simply reflect high population densities, and to detect cases of attraction or avoidance among conspecifics. They have been used to estimate the impact of population density, speeds of movement and size on rates of encounter between members of the opposite sex, between gametes, between predators and prey, and between observers and the individuals that they are counting. One limitation of published models has been that they predict rates of encounter, but give no means of determining whether observations differ significantly from predictions. Another uncertainty is the robustness of the predictions when animal movements deviate from the model’s assumptions in specific, biologically relevant ways. Here, we review applications of the ideal gas model, derive extensions of the model to cover some more realistic movement patterns, correct several errors that have arisen in the literature, and show how to generate confidence limits for expected rates of encounter among independently moving individuals. We illustrate these results using data from mangabey monkeys originally used along with the ideal gas model to argue that groups avoid each other. Although agent‐based simulations provide a more flexible alternative approach, the ideal gas model remains both a valuable null model and a useful, less onerous, approximation to biological reality.
On the electrodetection threshold of aquatic vertebrates with ampullary or mucous gland electroreceptor organs
Authors: Peters Rob C. , Eeuwes Lonneke B. M. , Bretschneider Franklin
Published: September 2007

Reinterpretation of research on the electric sense in aquatic organisms with ampullary organs results in the following conclusions.

The detection limit of limnic vertebrates with ampullary organs is 1 μVcm−1, and of marine fish is 20 nVcm−1. Angular movements are essential for stimulation of the ampullary system in uniform d.c. fields. Angular movements in the geomagnetic field also generate induction voltages, which exceed the 20 nVcm−1 limit in marine fish. As a result, marine electrosensitive fish are sensitive to motion in the geomagnetic field, whereas limnic fish are not.

Angular swimming movements generate a.c. stimuli, which act like the noise in a stochastic resonance system, and result in a detection threshold in marine organisms as low as 1 nVcm−1.

Fish in the benthic space are exposed to stronger electric stimuli than fish in the pelagic space. Benthic fish scan the orientation plane for the maximum potential difference with their raster of electroreceptor organs, in order to locate bioelectric prey. This behaviour explains why the detection threshold does not depend on fish size. Pelagic marine fish are mainly exposed to electric fields caused by movements in the geomagnetic field. The straight orientation courses found in certain shark species might indicate that the electric sense functions as a simple bisensor system. Symmetrical stimulation of the sensory raster would provide an easy way to keep a straight course with respect to a far‐field stimulus. The same neural mechanism would be effective in the location of a bioelectric prey generating a near‐field stimulus.

The response criteria in conditioning experiments and in experiments with spontaneous reactions are discussed.
Mammalian evolution and biomedicine: new views from phylogeny
Authors: Springer Mark S. , Murphy William J.
Published: September 2007

Recent progress resolving the phylogenetic relationships of the major lineages of mammals has had a broad impact in evolutionary biology, comparative genomics and the biomedical sciences. Novel insights into the timing and historical biogeography of early mammalian diversification have resulted from a new molecular tree for placental mammals coupled with dating approaches that relax the assumption of the molecular clock. We highlight the numerous applications to come from a well‐resolved phylogeny and genomic prospecting in multiple lineages of mammals, from identifying regulatory elements in mammalian genomes to assessing the functional consequences of mutations in human disease loci and those driving adaptive evolution.
Ecology of Australia: the effects of nutrient‐poor soils and intense fires
Authors: Orians Gordon H. , Milewski Antoni V.
Published: September 2007

Australia, the flattest, driest, and geologically oldest vegetated continent, has a uniquely high proportion of nutrient‐poor soils. We develop a “Nutrient‐Poverty/Intense‐Fire Theory,” which postulates that most anomalous features of organisms and ecosystems of Australia are the evolutionary consequences of adaptations to nutrient poverty, compounded by intense fire that tends to occur as a result of nutrient poverty. The fundamental tenet of the theory is that plants growing in environments with plentiful light and periodic adequate moisture, but on soils poor in phosphorus, zinc, and other indispensible nutrients, can synthesize carbohydrates in excess of the amount that can be combined with, or catalyzed by, these nutrients for metabolism and production of nutrient‐rich foliage and reproductive tissues. They use this “expendable energy” to produce well‐defended foliage, large quantities of lignified tissues, and readily digestible exudates. Rapid accumulation of nutrient‐poor biomass, a result of low rates of herbivory, provides fuel for intense fire. Intense fire exacerbates nutrient poverty by volatilizing certain micronutrients critical for animals. Anomalous features of organisms of Australia that can be explained by this theory, rather than by climate or phylogenetic history alone, include the following: most woody plants have long‐lived, durable foliage; plants defend their tissues primarily with carbon‐rich but nutrient‐poor compounds; an unusually high proportion of plants protects seeds from fire and granivores in sturdy, woody capsules or follicles; plants allocate unusually large amounts of expendable energy to production of carbon‐based exudates, such as nectar and gums; an unusually high proportion of plant species is pollinated by vertebrates that average larger size than pollinators on other continents; herbivores are small and have slow metabolism; there are no ruminants, mammals that eat mainly subterranean plant matter, or fungus‐culturing termites and ants; vegetation dominated by leaf‐spinescent plants is more extensive than vegetation dominated by stem‐spinescent plants; nitrogen‐fixing plants are major components of most vegetation types; there is a higher proportion of myrmecochorous plant species than on any other continent; there are hardly any stem‐succulent and few leaf‐succulent, perennial, non‐halophytic plant species; and an unusually high proportion of bird species breeds cooperatively. Although the Nutrient‐Poverty/Intense‐Fire Theory can provide plausible explanations for these anomalous features, some puzzles remain, among them the great success of introduced herbivores, the lack of grazers on extensive grasslands on cracking clays, the apparently low productivity of ants, and the prominence of the parasitic plants of Australia. By examining the ratios of available energy to nutrients, particularly scarce nutrients, ecologists may identify processes not previously recognized as important for life forms or biotic adaptation on other continents.
The sense of smell: molecular basis of odorant recognition
Authors: Zarzo Manuel
Published: September 2007

Most animal species rely on odorant compounds to locate food, predators, or toxins. The sense of smell is also involved in animal communication, and revealing the underlying mechanisms will therefore facilitate a deeper understanding of animal behaviour. Since the 1940s different theories have speculated on the fundamental basis of olfaction. It was assumed that odorant molecules were recognized by selective protein receptors in the nose, triggering a nervous signal processed by the brain. The discovery of these receptors in the early 1990s allowed great progress in understanding the physiological and biochemical principles of olfaction. An overview of the different mechanisms involved in the coding of odour character as well as odour intensity is presented here, focusing on the biochemical basis of odorant recognition. Despite the enormous progress achieved in recent years, details of odorant‐receptor interaction at the molecular level and the mechanisms of olfactory receptor activation are poorly understood. The likely role of metal ions in odorant recognition is discussed, and also the perireceptor events involved in odorant transport and biotransformation, with a view to providing a comprehensive overview of mammalian olfaction to guide future computational structural models and the design of functional experiments. Recent studies have analysed the olfactory genome of several species, providing information about the evolution of olfaction. The role of the olfactory system in animal communication is also described.
Leave it all behind: a taxonomic perspective of autotomy in invertebrates
Authors: Fleming Patricia A. , Muller Davina , Bateman Philip W.
Published: September 2007

Autotomy is defined herein as the shedding of a body part, where (1) the loss of the body part is defensive (autotomy helps prevent the whole animal from being compromised and is in response to external stimuli); (2) shearing occurs by an intrinsic mechanism along a breakage plane (there has been selection for certain body parts to be pulled off easily); and (3) the loss is controlled ‐ the animal moves away from the trapped limb, the loss is under some form of central control (neural or hormonal), or the body part is detached quickly.

Autotomy (under this defensive definition) has evolved independently for a diverse array of body parts in many taxa; we have summarised available information for over 200 invertebrate species. The advantages of autotomy include escape from entrapment, an effective form of attack, expulsion of an infected body part or in limiting wounding. We discuss how the incidence of autotomy may therefore be correlated with various traits such as limb function, sex differences, other defence mechanisms, habitat disturbance, and sociality. There are also costs associated with autotomy. Short‐term costs include loss of a specialised appendage or organ, reduced speed and stability, or even death. Long‐term costs include compromised foraging and feeding (often leading to reduced growth), altered anti‐predator, competitive or reproductive behaviour, and even defective development. Regenerating lost appendages may also incur significant costs for the individual. We examine the costs and benefits of autotomy, and discuss the evolutionary selective pressures that contribute to the prevalence and effectiveness of autotomy in invertebrates.
Exploring the role of vision in social foraging: What happens to group size, vigilance, spacing, aggression and habitat use in birds and mammals that forage at night?
Authors: Beauchamp Guy
Published: September 2007

I examined the role of vision in social foraging by contrasting group size, vigilance, spacing, aggression and habitat use between day and night in many species of birds and mammals. The literature review revealed that the rate of predation/disturbance was often reduced at night while food was considered more available. Social foraging at night was prevalent in many species suggesting that low light levels at night are not sufficient to prevent the formation and cohesion of animal groups. Group sizes were similar or larger at night than during the day in more than half the bird populations and in the majority of mammal populations. Factors such as calls, feeding noises or smells may contribute to the formation and cohesion of groups at night. Larger numbers of foragers at night may also facilitate the aggregation of more foragers. Vigilance levels were usually lower at night perhaps as a response to the lower predation risk or to the decreased value of scanning for predators that are difficult to locate. Low light levels may also make visual cues that promote aggression less conspicuous, which may be a factor in the lower levels of aggression documented at night. Spacing varied as a function of time of day in response to changes in foraging mode or food availability. Habitats that are avoided during the day were often used at night. Foraging at night presents birds and mammals with a new set of constraints that influence group size, time budgeting and habitat use.
Mask‐ and distractor‐triggered inhibitory processes in the priming of motor responses: An EEG study
Authors: Jaśkowski Piotr , Białuńska Anita , Tomanek Monika , Verleger Rolf
Published: September 2007

Masked stimuli presented near the threshold of conscious awareness may act as primes, affecting responses to subsequent targets. With arrows as primes and targets, the prime–mask–target sequence has been shown to evoke triphasic lateralized readiness potentials (LRP) with two phases of imbalance between hemispheres preceding the target‐related contralateral preponderance of negativity: first a negative, then a positive preponderance contralateral to prime direction. The present article provides evidence that the second wave is related to mask presentation and reflects inhibitory processing independent of reductions in prime visibility, even being evoked by nonmasking distractors that leave the prime fully accessible for consciousness. Of all hypotheses put forward to account for inverse effects in masked priming, this finding is most compatible with the mask‐triggered inhibition hypothesis suggested byP. Jaśkowski (2007).