bluuebunny/crossref_metadata_2025_split huggingface dataset:
The evolution of floral scent: the influence of olfactory learning by insect pollinators on the honest signalling of floral rewards
Authors: Wright Geraldine A. , Schiestl Florian P. 
Published: September 2009

Summary1. The evolution of flowering plants has undoubtedly been influenced by a pollinator’s ability to learn to associate floral signals with food. Here, we address the question of ‘why’ flowers produce scent by examining the ways in which olfactory learning by insect pollinators could influence how floral scent emission evolves in plant populations.2. Being provided with a floral scent signal allows pollinators to learn to be specific in their foraging habits, which could, in turn, produce a selective advantage for plants if sexual reproduction is limited by the income of compatible gametes. Learning studies with honeybees predict that pollinator‐mediated selection for floral scent production should favour signals which are distinctive and exhibit low variation within species because these signals are learned faster. Social bees quickly learn to associate scent with the presence of nectar, and their ability to do this is generally faster and more reliable than their ability to learn visual cues.3. Pollinators rely on floral scent as a means of distinguishing honestly signalling flowers from deceptive ones. Furthermore, a pollinator’s sensitivity to differences in nectar rewards can bias the way that it responds to floral scent. This mechanism may select for flowers that provide olfactory signals as an honest indicator of the presence of nectar or which select against the production of a detectable scent signal when no nectar is present.4. We expect that an important yet commonly overlooked function of floral scent is an improvement in short‐term pollinator specificity which provides an advantage to both pollinator and plant over the use of a visual signal alone. This, in turn, impacts the evolution of plant mating systems via its influence on the species‐specific patterns of floral visitation by pollinators.
Floral volatiles controlling ant behaviour
Authors: Willmer Pat G. , Nuttman Clive V. , Raine Nigel E. , Stone Graham N. , Pattrick Jonathan G. , Henson Kate , Stillman Philip , McIlroy Lynn , Potts Simon G. , Knudsen Jeffe T. 
Published: September 2009

Summary1. Ants show complex interactions with plants, both facultative and mutualistic, ranging from grazers through seed predators and dispersers to herders of some herbivores and guards against others. But ants are rarely pollinators, and their visits to flowers may be detrimental to plant fitness.2. Plants therefore have various strategies to control ant distributions, and restrict them to foliage rather than flowers. These ‘filters’ may involve physical barriers on or around flowers, or ‘decoys and bribes’ sited on the foliage (usually extrafloral nectaries ‐ EFNs). Alternatively, volatile organic compounds (VOCs) are used as signals to control ant behaviour, attracting ants to leaves and/or deterring them from functional flowers. Some of the past evidence that flowers repel ants by VOCs has been equivocal and we describe the shortcomings of some experimental approaches, which involve behavioural tests in artificial conditions.3. We review our previous study of myrmecophytic acacias, which usedin situexperiments to show that volatiles derived from pollen can specifically and transiently deter ants during dehiscence, the effects being stronger in ant‐guarded species and more effective on resident ants, both in African and Neotropical species. In these plants, repellence involves at least some volatiles that are known components of ant alarm pheromones, but are not repellent to beneficial bee visitors.4. We also present new evidence of ant repellence by VOCs in temperate flowers, which is usually pollen‐based and active on common European ants. We use these data to indicate that across a wide range of plants there is an apparent trade‐off in ant‐controlling filter strategies between the use of defensive floral volatiles and the alternatives of decoying EFNs or physical barriers.
Testing the potential for conflicting selection on floral chemical traits by pollinators and herbivores: predictions and case study
Authors: Kessler André , Halitschke Rayko 
Published: September 2009

Summary1. There are myriad ways in which pollinators and herbivores can interact via the evolutionary and behavioural responses of their host plants.2. Given that both herbivores and pollinators consume and are dependent upon plant‐derived nutrients and secondary metabolites, and utilize plant signals, plant chemistry should be one of the major factors mediating these interactions.3. Here we build upon a conceptual framework for understanding plant‐mediated interactions of pollinators and herbivores. We focus on plant chemistry, in particular plant volatiles and aim to unify hypotheses for plant defence and pollination. We make predictions for the evolutionary outcomes of these interactions by hypothesizing that conflicting selection pressures from herbivores and pollinators arise from the constraints imposed by plant chemistry.4. We further hypothesize that plants could avoid conflicts between pollinator attraction and herbivore defence through tissue‐specific regulation of pollinator reward chemistry, as well as herbivore‐induced changes in flower chemistry and morphology.5. Finally, we test aspects of our predictions in a case study using a wild tomato species,Solanum peruvianum, to illustrate the diversity of tissue‐specific and herbivore‐induced differences in plant chemistry that could influence herbivore and pollinator behaviour, and plant fitness.
Spectral analysis of cyclostationary time-series: a robust method
Authors: Lepage K. Q. , Thomson D. J. 
Published: September 2009

SummaryA robust, spectral method of analysing cyclostationary time-series is introduced. The robust method involves an adaptation of an autoregressive one-step ahead predictive cleaning process. Standard, robust spectrum estimates are compared against the robust estimate computed using the presented procedure and found to be inferior, both in simulation and on seismic velocity data obtained from station NNA, situated in Ñaña, Peru.
Ovariectomy‐associated changes in bone mineral density and bone marrow haematopoiesis in rats
Authors: Lei Zhu , Xiaoying Zhao , Xingguo Lu 
Published: September 2009

SummaryThe relationship between the bone mass loss and bone marrow haematopoiesis in osteoporosis remains obscure. We selected 3‐month‐old female Sprague–Dawley rats and randomly divided them into six groups. Three groups were ovariectomized (OVX), while the other three groups were sham operated (Sham). Four, 8 and 12 weeks after the surgical procedure, the rats were euthanized and sampled. The left femur was used for measurement of bone mineral density (BMD). The right femur distal metaphysic cancellous bone was processed for morphological evaluation. Our results showed that the femur BMD in the 4‐week OVX group was not significantly decreased compared with that of the 4‐week Sham group, but that the volume of adipose tissue in the bone marrow was markedly increased. The femur BMD in the 8‐week OVX group was decreased significantly compared with that of the 8‐week Sham group (P < 0.05). Meanwhile, the volume of haematopoietic tissue decreased and the volume of adipose tissue increased. The number of megakaryocytes was decreased (P < 0.05). Interestingly, the osteoclasts and mast cells were increased in number in the 8‐week OVX group (P < 0.05). These changes became obvious in the 12‐week OVX rats, in contrast to the Sham groups. The volume of trabecular bone and the number of osteoblasts in the 12‐week OVX group decreased significantly. Increased reticulin fibres were observed only in the 12‐week OVX group. Our studies demonstrated a reciprocal correlation between bone‐forming osteoblasts and marrow adipose tissue and suggest that OVX rats may be valuable as an animal model to study hypohaemopoiesis.
Mutated K‐rasAsp12 promotes tumourigenesis in ApcMin mice more in the large than the small intestines, with synergistic effects between K‐ras and Wnt pathways
Authors: Luo Feijun , Brooks David G. , Ye Hongtao , Hamoudi Rifat , Poulogiannis George , Patek Charles E. , Winton Douglas J. , Arends Mark J. 
Published: September 2009

SummaryK‐ras mutations are found in 40–50% of human colorectal adenomas and carcinomas, but their functional contribution remains incompletely understood. Here, we show that a conditional mutant K‐ras mouse model (K‐rasAsp12/Cre), with transient intestinal Cre activation by β‐Naphthoflavone (β‐NF) treatment, displayed transgene recombination and K‐rasAsp12 expression in the murine intestines, but developed few intestinal adenomas over 2 years. However, when crossed with ApcMin/+ mice, the K‐rasAsp12/Cre/ApcMin/+ offspring showed acceleration of intestinal tumourigenesis with significantly changed average lifespan (P < 0.05) decreased to 18.4 ± 5.4 weeks from 20.9 ± 4.7 weeks (control ApcMin/+ mice). The numbers of adenomas in the small intestine and large intestine were significantly (P < 0.01) increased by 1.5‐fold and 5.7‐fold, respectively, in K‐rasAsp12/Cre/ApcMin/+ mice compared with ApcMin/+ mice, with the more marked increase in adenoma prevalence in the large intestine. To explore possible mechanisms for K‐rasAsp12 and ApcMin co‐operation, the Mitogen‐activated protein kinase (Mapk), Akt and Wnt signalling pathways, including selected target gene expression levels, were evaluated in normal large intestine and large intestinal tumours. K‐rasAsp12 increased activation of Mapk and Akt signalling pathway targets phospho‐extracellular signal‐regulated kinase (pErk) and pAkt, and increased relative expression levels of Wnt pathway targets vascular endothelial growth factor (VEGF), gastrin, cyclo‐oxygenase 2 (Cox2) and T‐cell lymphoma invasion and metastasis 1 (Tiam1) in K‐rasAsp12/Cre/ApcMin/+ adenomas compared with that of ApcMin/+ adenomas, although other Wnt signalling pathway target genes such as Peroxisome proliferator‐activated receptor delta (PPARd), matrix metalloproteinase 7 (MMP7), protein phosphatase 1 alpha (PP1A) and c‐myc remained unchanged. In conclusion, intestinal expression of K‐rasAsp12 promotes mutant Apc‐initiated intestinal adenoma formation in vivo more in the large intestine than the small intestine, with evidence of synergistic co‐operation between mutant K‐ras and Apc involving increased expression of some Wnt‐pathway target genes.
Hepatic extracellular matrix alterations in dogs naturally infected with Leishmania (Leishmania) chagasi
Authors: Melo Ferdinan Almeida , Moura Eliane Perlatto , Ribeiro Raul Rio , Alves Cíntia Fontes , Caliari Marcelo Vidigal , Tafuri Washington Luiz , Da Silva Calabrese Kátia , Tafuri Wagner Luiz 
Published: September 2009

SummaryThe aim of this work was to study alterations in the extracellular matrix of liver in dogs naturally infected with Leishmania (Leishmania) chagasi that are correlated with clinical aspects and with histological, parasitological and immunological findings. The study was carried out on 30 dogs, 10 uninfected (control group) and 20 infected. The infected animals were further divided into two groups: an asymptomatic group of 10 dogs without clinical signs of the disease; and a symptomatic group of 10 dogs with classical clinical signs. All thirty animals were mongrel dogs of undefined age, obtained from the municipality of Belo Horizonte, MG, metropolitan area. During necropsy, liver fragments were collected and fixed in 10% buffered formaldehyde for histological examination. Paraffined sections of the tissues were stained with haematoxylin–eosin, Gomori’s ammoniacal silver stain for reticular fibres and strepto‐avidin peroxidase for immunohistochemical detection of Leishmania amastigotes. Frozen tissue sections were stained by immunofluorescence for fibronectin (FN) and laminin (LN). Liver collagen deposition was significantly greater in the infected than the control animals and differed significantly between the symptomatic and asymptomatic dogs. There was a positive correlation between the parasite load and liver collagen deposition. The increased collagen deposition in infected animal livers may be associated with the parasite burden. Adhesive FN and LN fibres were significantly more highly expressed in the livers of symptomatic than of asymptomatic dogs. Our results demonstrate that canine visceral leishmaniasis causes fibrogenesis in liver, associated with the parasite load and degenerative processes.
Professional nursing culture on a trauma unit: experiences of patients and staff
Authors: Tutton Elizabeth , Seers Kate , Langstaff Debbie 
Published: September 2009

AbstractTitle.  Professional nursing culture on a trauma unit: experiences of patients and staff Aim.  This paper is a report of a study to explore the day‐to‐day experiences of patients and staff on a unit dedicated to the care of adult patients who have sustained an injury.Background.  With the numbers of people suffering traumatic injury increasing, provision of their acute care and rehabilitation is also of increasing concern. Staff have the potential to optimize recovery but the factors that facilitate or inhibit this in practice are unclear.Method.  This ethnographic study took place on a trauma unit in the United Kingdom between November 2004 and January 2006. Sixteen periods of observation, qualitative interviews with 40 patients and 19 staff, and four focus groups with staff were undertaken. Thematic analysis was conducted and data were analysed by sentence.Findings.  The dynamic process of patient‐centred care was expressed through the themes of closeness, therapeutic care and working as a team. Closeness conveyed the sudden and devastating nature of injury, and the necessity for staff to let go of feelings to maintain a positive momentum. Therapeutic care highlighted the social connection between the staff and the patients, combined with a proactive dynamic approach to care. Working as a team identified the importance of maintaining expertise and making the system work for patients to ensure the best possible care.Conclusion.  By identifying the context and processes that facilitate recovery, it becomes possible to provide a framework for individuals and units to develop and improve practice that enhances recovery. These findings may be useful for other similar areas of care.
Children’s experiences of visiting a seriously ill/injured relative on an adult intensive care unit
Authors: Knutsson Susanne , Samuelsson Ingrid Pramling , Hellström Anna‐Lena , Bergbom Ingegerd 
Published: September 2009

AbstractTitle.  Children’s experiences of visiting a seriously ill/injured relative on an adult intensive care unit Aim.  This paper is a report of a study of children’s experiences of visiting a seriously ill/injured relative in an intensive care unit.Background.  Little attention has been paid to children’s experiences and needs when visiting a relative being cared for at a high technological adult intensive care unit. Instead, the focus has been on adult’s experiences and needs.Method.  In 2004, 28 children (14 girls, 14 boys) aged 4–17 years who had visited an adult relative were interviewed 3 months after the visit. A hermeneutic approach was used when interpreting and analysing the text.Findings.  Four themes were generated from the data: It meant waiting, It was strange, It was white and It was good. Waiting was experienced as difficult, increasing the feeling of uncertainty, exclusion and separation, which in turn led to tension and concern. ‘It was strange’ was perceived as unfamiliar but also with interest and curiosity. The experience of the intensive care unit was that it was white. Everything in the patient’s room was experienced as white and gloomy. It lacked joy. ‘It was good’ was stated about the outcome of the visit because through this they were given the opportunity to meet and see the relative by themselves. This evoked feelings of relief and joy. The visit did not seem to frighten the child; instead it generated feelings of release and relief.Conclusion.  Children’s experiences of visiting an adult intensive care unit seem to support theories that emphasize the involvement and participation of children in family matters.
What determines a species’ geographical range? Thermal biology and latitudinal range size relationships in European diving beetles (Coleoptera: Dytiscidae)
Authors: Calosi Piero , Bilton David T. , Spicer John I. , Votier Stephen C. , Atfield Andrew 
Published: September 2009

Summary1. The geographical range sizes of individual species vary considerably in extent, although the factors underlying this variation remain poorly understood, and could include a number of ecological and evolutionary processes. A favoured explanation for range size variation is that this result from differences in fundamental niche breadths, suggesting a key role for physiology in determining range size, although to date empirical tests of these ideas remain limited.2. Here we explore relationships between thermal physiology and biogeography, whilst controlling for possible differences in dispersal ability and phylogenetic relatedness, across 14 ecologically similar congeners which differ in geographical range extent; European diving beetles of the genusDeronectesSharp (Coleoptera, Dytiscidae). Absolute upper and lower temperature tolerance and acclimatory abilities are determined for populations of each species, following acclimation in the laboratory.3. Absolute thermal tolerance range is the best predictor of both species’ latitudinal range extent and position, differences in dispersal ability (based on wing size) apparently being less important in this group. In addition, species’ northern and southern range limits are related to their tolerance of low and high temperatures respectively. In all cases, absolute temperature tolerances, rather than acclimatory abilities are the best predictors of range parameters, whilst the use of independent contrasts suggested that species’ thermal acclimation abilities may also relate to biogeography, although increased acclimatory ability does not appear to be associated with increased range size.4. Our study is the first to provide empirical support for a relationship between thermal physiology and range size variation in widespread and restricted species, conducted using the same experimental design, within a phylogenetically and ecologically controlled framework.
Marker‐assisted determination of the relationship between body size and reproductive success and consequences for evaluation of adaptive life histories
Authors: MORRISSEY MICHAEL B. , FERGUSON MOIRA M. 
Published: September 2009

AbstractWe tested for differences in the predicted optimal ages at first maturity in brook charr (Salvelinus fontinalis) in Freshwater River, Newfoundland, when life‐history data were collated based on the marker‐assisted estimation of the relationship between body size and reproductive success rather than using fecundity as a surrogate for reproductive success. Jointly with capture–recapture data to estimate the growth and survival costs of reproduction, we found that weak relationships between body size and reproductive success generate selection against delayed maturation. This finding would not have held for females if the relationship between body size and fecundity had been used as a surrogate for the relationship between body size and reproductive success. This shows that predictions of optimal life histories can be qualitatively changed when using molecular markers to directly evaluate age‐ and/or size‐specific effects of body size on reproductive success.
An information‐theoretical approach to phylogeography
Authors: CARSTENS BRYAN C. , STOUTE HOLLY N. , REID NOAH M. 
Published: September 2009

AbstractData analysis in phylogeographic investigations is typically conducted in either a qualitative manner, or alternatively via the testing of null hypotheses. The former, where inferences about population processes are derived from geographical patterns of genetic variation, may be subject to confirmation bias and prone to overinterpretation. Testing the predictions of null hypotheses is arguably less prone to bias than qualitative approaches, but only if the tested hypotheses are biologically meaningful. As it is difficult to know a priori if this is the case, there is the general need for additional methodological approaches in phylogeographic research. Here, we explore an alternative method for analysing phylogeographic data that utilizes information theory to quantify the probability of multiple hypotheses given the data. We accomplish this by augmenting the model‐selection procedure implemented in ima with calculations of Akaike Information Criterion scores and model probabilities. We generate a ranking of 17 models each representing a set of historical evolutionary processes that may have contributed to the evolution of Plethodon idahoensis, and then quantify the relative strength of support for each hypothesis given the data using metrics borrowed from information theory. Our results suggest that two models have high probability given the data. Each of these models includes population divergence and estimates of ancestral θ that differ from estimates of descendent θ, inferences consistent with prior work in this system. However, the models disagree in that one includes migration as a parameter and one does not, suggesting that there are two regions of parameter space that produce model likelihoods that are similar in magnitude given our data. Results of a simulation study suggest that when data are simulated with migration, most of the optimal models include migration as a parameter, and further that when all of the shared polymorphism results from incomplete lineage sorting, most of the optimal models do not. The results could also indicate a lack of precision, which may be a product of the amount of data that we have collected. In any case, the information‐theoretic metrics that we have applied to the analysis of our data are statistically rigorous, as are hypothesis‐testing approaches, but move beyond the ‘reject/fail to reject’ dichotomy of conventional hypothesis testing in a manner that provides considerably more flexibility to researchers.
Implications of isolation and low genetic diversity in peripheral populations of an amphi‐Atlantic coral
Authors: NUNES F. , NORRIS R. D. , KNOWLTON N. 
Published: September 2009

AbstractLimited dispersal and connectivity in marine organisms can have negative fitness effects in populations that are small and isolated, but reduced genetic exchange may also promote the potential for local adaptation. Here, we compare the levels of genetic diversity and connectivity in the coral Montastraea cavernosa among both central and peripheral populations throughout its range in the Atlantic. Genetic data from one mitochondrial and two nuclear loci in 191 individuals show that M. cavernosa is subdivided into three genetically distinct regions in the Atlantic: Caribbean‐North Atlantic, Western South Atlantic (Brazil) and Eastern Tropical Atlantic (West Africa). Within each region, populations have similar allele frequencies and levels of genetic diversity; indeed, no significant differentiation was found between populations separated by as much as 3000 km, suggesting that this coral species has the ability to disperse over large distances. Gene flow within regions does not, however, translate into connectivity across the entire Atlantic. Instead, substantial differences in allele frequencies across regions suggest that genetic exchange is infrequent between the Caribbean, Brazil and West Africa. Furthermore, markedly lower levels of genetic diversity are observed in the Brazilian and West African populations. Genetic diversity and connectivity may contribute to the resilience of a coral population to disturbance. Isolated peripheral populations may be more vulnerable to human impacts, disease or climate change relative to those in the genetically diverse Caribbean‐North Atlantic region.