bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of metal stress on life history divergence and quantitative genetic architecture in a wolf spider
Authors: HENDRICKX F. , MAELFAIT J.‐P. , LENS L. 
Published: November 2007

AbstractEffects and consequences of stress exposure on life history strategies and quantitative genetic variation in wild populations remain poorly understood. We here study whether long‐term exposure to heavy metal pollution may result in alternative life history strategies and alter quantitative genetic properties in natural populations of the wolf spiderPirata piraticus. Offspring originating from a reference and a metal contaminated population and their reciprocal hybrid cross were bred in a half‐sib mating scheme and subsequently reared in cadmium contaminated vs. clean environment. Results from this experiment provided evidence for a genetically based reduced growth rate and increased egg size in the contaminated population. Growth rate reduction in response to cadmium contamination was only observed for the reference population. Animal model analysis revealed that heritability for growth rate was large for the reference population under reference conditions, but much lower under metal stressed conditions, caused by a strong decrease in additive genetic variance. Heritability for growth of the metal contaminated population was very low, even under reference conditions. Initial size of the offspring was primarily determined by maternal effects, whereas egg size produced by the offspring was determined by both sire and dam effects, indicating that egg size determination is under control of the female genotype. In conclusion, these results show that metal stress can not only affect life history variation in natural populations, but also decreases the expression as well as the of the amount of genetic variation for particular life history traits.
Sympatric genetic differentiation of a generalist pathogenic fungus, Botrytis cinerea, on two different host plants, grapevine and bramble
Authors: FOURNIER E. , GIRAUD T. 
Published: November 2007

AbstractPrime candidates for sympatric ecological divergence include parasites that differentiate via host shifts, because different host species exert strong disruptive selection and because both hosts and parasites are continually co‐evolving. Sympatric divergence may be fostered even more strongly in phytopathogenic fungi, in particular those where sex must occur on the host, which allows adaptation alone to restrict gene flow between populations developing on different hosts. We sampled populations of Botrytis cinerea, a generalist ascomycete fungus, on sympatric grapes and brambles in six regions in France. Microsatellite data were analyzed using standard population genetics, a population graph analysis and a Bayesian approach. In addition to confirming that B. cinerea reproduces sexually, our results showed that the fungal populations on the two hosts were significantly differentiated, indicating restricted gene flow, even in sympatry. In contrast, only weak geographical differentiation could be detected. These results support the possibility of sympatric divergence associated with host use in generalist parasites.
The Effects of Predation Risk, Food Abundance, and Population Size on Group Size of Brown‐Headed Cowbirds (Molothrus ater)
Authors: Morgan Timothy , Fernández‐Juricic Esteban 
Published: November 2007

AbstractSocial and ecological conditions can influence flock formation (e.g. number of flocks, flock size, etc.) depending on the degree of social attraction of a species. We studied group formation in brown‐headed cowbirds (Molothrus ater) over short time periods (30 min) in two semi‐natural experiments conducted under controlled conditions. First, we determined the shape of the relationship between intake rate and flock size by manipulating group size in a single enclosure. Second, we assessed the role of population size, food abundance, and predation risk, and their interactions, in flock size formation in a system of four enclosures (two with and two without food) connected to a central refuge patch. In the first experiment, we found that pecking rates peaked at intermediate flock sizes (three to six individuals), which was influenced by greater availability of foraging time and more aggressive interactions in large groups. In the second experiment, flock sizes in the patches with food increased with population size likely due to the benefits of patch exploitation in groups. Flock size decreased after predator attack probably because refuge availability reduced perceived predation risk more than flocking in larger groups. Food abundance had minor effects, varying flock sizes between the two patches with food, under high food availability conditions when population size was high, probably due to social cohesion effects. Our results suggest that: (1) this species has an inverted‐U food intake–group size relationship with a range of intake‐maximizing flock sizes rather than a single peak, (2) the presence of a near refuge modifies the expected benefits of group patch exploitation under high predation risk, and (3) an increase in population size would more likely be translated into rapid increases in the size of the flocks rather than in more new flocks.
Kinship Discrimination and Effects on Social Rank and Aggressiveness Levels in Iberian Red Deer Hinds
Authors: Ceacero Francisco , Landete‐Castillejos Tomás , García Andres J. , Estévez José A. , Gallego Laureano 
Published: November 2007

AbstractKin recognition is a widespread phenomenon that allows individuals to benefit by enhancing their inclusive fitness, and one of its most common forms is reducing aggressiveness towards relatives. We carried out an experiment with Iberian red deer hinds (Cervus elaphus hispanicus) in order to examine kin biases in dominance behaviour and its consequences on social rank. Three enclosed groups (n = 36, 23 and 21, respectively) were monitored during two lactation seasons and social rank hierarchies were assessed by analysing aggressive interactions matrices with Matman 1.1 software. Aggressive interactions between related hinds was significantly smaller than expected (χ2 = 5.02, df = 1, p = 0.025), not only between mother and daughter but also in second and third kinship degrees. Although rates of aggressiveness were similar to data published relating free‐ranging C. e. scoticus, aggressive interactions with relatives were significantly smaller (χ2 = 39.0, df = 1, p < 0.001). This reduction of aggressiveness between related hinds was not the result of these hinds having a lower social rank: social rank was only related to age and weight, but not to kinship degree, calf sex or calving date. The decrease of aggressiveness towards first‐, second‐ and third‐degree relatives shows a complex kin recognition system in deer. Possible nepotistic roles in lactation include preventing milk thefts by non‐kin and disturbing feeding of unrelated hinds.
Determinants of Male Spacing Behaviour in Panacanthus pallicornis (Orthoptera: Tettigoniidae)
Authors: Chamorro‐R Juliana , Montealegre‐Z Fernando , González‐O Ranulfo 
Published: November 2007

Abstract Panacanthus pallicornis is a neotropical species of katydid endemic to Colombia that inhabits premontane forests, and individuals are found in regenerating (RF) and dense forest (DF) habits. Members of this species are made conspicuous by their colouration, remarkable defensive body thorns and the loud mating calls of the males. Through capture, marking, and recapture, we determined singing‐site characteristics in two different natural habitats: an RF and a DF. Using nearest neighbour analysis, we found male distribution tends to uniformity in forest habitats, but in the RF, male distribution is more random. Males also showed preference for high singing sites and these were correlated with host plant height. Although host plants in DF were taller than those in the RF, male’s perch preference was independent from the habitat; and in RF, males select lower perches. To investigate if male spacing was a function of the calling song, we manipulated two groups of males from a different population, one group deafened (tympanic membranes torn), and another control group with tympanic membranes intact. Insects were released from a single location in the two different zones of similar area. After a number of days we measured male displacement, and found that the deafened group distribution tended to aggregation, while the control group spread throughout the experimental zone with a random distribution. These results suggest that male spacing behaviour is one of the functions of the calling song. Based on a pre‐established phylogenetic framework of the genus Panacanthus, we discuss some implications for the evolution of the calling song of P. pallicornis in both RF and DF.
Field Observations of Agonism in the Crayfish, Orconectes rusticus: Shelter Use in a Natural Environment
Authors: Martin Arthur L. , Moore Paul A. 
Published: November 2007

AbstractCrayfish are aggressive animals that compete to acquire resources such as shelters, food, and mates. Shelters are a primary resource that crayfish use for protection from conspecifics and predators. Despite the importance of this resource, no field research has been performed that studies the acquisition and control of this resource. The present study examines shelter use in a natural habitat and the impact that shelter ownership has on the intensity and outcome of agonistic encounters. A stationary underwater camera was used to observe crayfish, Orconectes rusticus, shelter use and agonistic interactions in a natural lake environment. These shelters were formed naturally in iron outcroppings found on the limestone and detritus benthos. Crayfish activity and shelter use was found to be dependent upon a circadian cycle with most of the shelter use occurring during the morning to early afternoon (05:00–13:00 hours). Agonistic encounters in the presence of shelters resulted in short, low intensity interactions. Interestingly, fight outcomes were not significantly affected by shelter ownership, but were primarily determined by size differential of combatants. This outcome may be due to the prevalence of shelters within this habitat. Contrary to laboratory studies, these results indicate that shelter ownership may not be an important factor in determining resource‐holding potential in some habitats.
Mate Choice by Non‐Virgin Females Contributes to Reproductive Isolation between Populations of the Harlequin Beetle‐Riding Pseudoscorpion
Authors: Zeh Jeanne A. , Zeh David W. 
Published: November 2007

AbstractDetermining whether reproductive isolation evolves through mate choice and/or gametic factors that prevent fertilization or through the post‐zygotic mechanisms of hybrid sterility or inviability is fundamental to understanding speciation. Investigation of the pre‐ and post‐zygotic components of reproductive isolation is facilitated in the pseudoscorpion, Cordylochernes scorpioides, by its indirect method of sperm transfer and viviparous embryonic development. Previous research on this species, in which mate discrimination was assessed in virgin females, suggested that female choice played only a minor role in reproductive isolation between populations from French Guiana and Panamá. Here, in a study of three allopatric populations of C. scorpioides from Panamá, we assessed mating‐stage isolation in both virgin and once‐mated females, and found that female discrimination depends critically on mating status. Virgin females were almost invariably receptive, showing no tendency to discriminate against males from allopatric populations. By contrast, non‐virgin females were significantly more likely to reject foreign males than males from their own population. Male sexual motivation could not account for differences in either female sexual receptivity or male success in sperm transfer. Allopatric and sympatric males did not differ in number of spermatophores deposited as either a female’s first or second mate. Nonetheless, allopatric males achieved significantly lower sperm transfer success not only with choosy, non‐virgin females but also with virgin females. Given the lack of behavioral discrimination by virgin females, female receptivity was not the only factor influencing differences in sperm transfer success. Multivariate analysis of spermatophore morphology suggests that the higher failure rate of matings between allopatric males and virgin females resulted from population differences in sperm packet architecture. Overall, our findings indicate that assessment of discrimination against allopatric males that is limited to virgin females may seriously underestimate the contribution of female mate choice to reproductive isolation between populations.
Wilson’s Storm Petrels Oceanites oceanicus Recognise the Olfactory Signature of Their Mate
Authors: Jouventin Pierre , Mouret Vincent , Bonadonna Francesco 
Published: November 2007

AbstractChemical signals in birds have rarely been considered as recognition cues. Nevertheless, recent experiments showed that several petrel species are able to recognize their nest by smell, and in at least one species even their mate. But the use of smell may be different across the petrel species and olfactory nest recognition appears to be dependent on species’ breeding biology. To increase our knowledge of individual olfactory recognition in petrels and the relationships between breeding biology and use of smell, we tested Wilson’s storm petrels Oceanites oceanicus in Antarctica. In previous experiments, these birds failed to home if rendered anosmic, but the method employed to obtain anosmia (potentially stressing birds) and the fact that they breed in 24‐h daylight suggest that they might use visual, rather than olfactory, cues to recognize their nest. Our birds were tested in T‐maze experiments where nest odours or partner odours were presented. Wilson’s storm petrels preferred odours of their own nest and mate. Results on olfactory nest recognition confirm and complete previous results, viz. anosmic Wilson’s storm petrels do not home. Storm petrels olfactory mate recognition suggests that this ability may be widespread in burrowing petrels and implements olfactory nest recognition.
Occurrence of Heterobasidion basidiocarps on cull pieces of Norway spruce left on cutting areas and in mature spruce stands
Authors: Müller M. M. , Heinonen J. , Korhonen K. 
Published: November 2007

SummaryFruiting of Heterobasidion on cull pieces and stumps of Norway spruce was investigated in cutting areas and mature spruce stands located in southern Finland. Cull pieces of variable size and showing butt rot were left on three clear‐cut areas and in one thinned stand. Additionally, a part of the cull pieces was transported to mature forest sites with closed canopy. During the succeeding 3–4 years the cull pieces were investigated annually for sporocarps of Heterobasidion, and the area of actively sporulating pore layer of each sporocarp was measured. Root bases of spruce stumps in the logging areas were excavated and sporocarps found on the stumps also measured. At the onset of the experiment, Heterobasidion spp. were isolated from 76% of the cull pieces showing butt rot; 85% of the isolates were identified as H. parviporum and 15% as H. annosum s.s. During the following 3–4 years sporocarps were found on 20% of the 1938 cull pieces where Heterobasidion butt rot was initially detected visually. Sporocarp formation was promoted by advancement of butt rot, increasing cull piece diameter and end‐to‐end ground contact, but restricted by the colonization of the cull piece by Stereum sanguinolentum. Between‐site differences were significant but could not be explained by differences in tree cover. At the end of the investigation period the average sporulating area of Heterobasidion sporocarp per metre of cull piece was higher than the average sporulating area per stump at three of four logging sites. Hence, leaving cull pieces containing Heterobasidion butt rot at logging areas in southern Finland can considerably increase local production of Heterobasidion spores.
How many cytological examinations should be performed for the diagnosis of malignant biliary stricture via an endoscopic nasobiliary drainage tube?
Authors: Uchida Naohito , Kamada Hideki , Ono Masahiro , Aritomo Yuichi , Masaki Tsutomu , Nakatsu Toshiaki , Kuriyama Shigeki 
Published: November 2007

AbstractBackground and Aim:  The sensitivity of bile cytology is recognized as being low. Repeating cytological sampling is likely to improve the sensitivity. The aim of this study is to determine the optimal number of repeated cytological sampling of bile obtained via an endoscopic nasobiliary drainage (ENBD) tube for the diagnosis of malignant biliary stricture.Methods:  Ninety‐eight patients with malignant biliary stricture who underwent ENBD were enrolled. Diagnoses included bile duct carcinoma (n = 53), pancreatic carcinoma (n = 28), carcinoma of the major papilla (n = 8), gallbladder carcinoma (n = 6), and hepatocellular carcinoma (n = 3). Bile was aspirated via an ENBD tube once a day and immediately evaluated cytologically.Results:  The median number of cytological samplings via an ENBD tube was 2.8 times (range, 1–10). In 40 of 98 patients with malignant biliary stricture, cytology was positive at the first cytological sampling (sensitivity 40.8%). Cytology was cumulatively positive in 71 of 98 patients (sensitivity 72.4%) from which repeated samples were taken. In 71 patients with positive cytology, correlation of the positive rate and the number of cytological samplings performed was investigated. In 68 of 71 (95.8%) patients with positive cytology, positive results were obtained by or at the sixth examination.Conclusions:  Bile cytology via an ENBD tube is an easy method, and has been shown to have relatively high sensitivity. The optimal number of repeated cytological samplings using bile obtained via an ENBD tube for the diagnosis of malignant biliary stricture was concluded to be six.
Factors influencing parental decision to consult for children with upper respiratory tract infection
Authors: Ng Chirk‐Jenn , Chia Yook‐Chin , Teng Cheong‐Lieng , Nik‐Sherina Hanafi 
Published: November 2007

Aim:  This study aimed to determine which factors could influence (i) parents’ decision to seek medical consultatin and (ii) their preference for either public or private medical service in children with upper respiratory tract infection.Methods:  This cross‐sectional study was conducted at the Gombak district, which is an urban area in Malaysia. We randomly selected parents of kindergarten children aged 4–5 years to participate in this questionnaire survey. The main outcome measures were predictors of early medical consultation and type of service utilisation (public versus private).Results:  We achieved a response rate of 84.5% (n = 1033/1223). 64.1% sought early medical consultation and 70.9% preferred to consult a private doctor. Early consultation was predicated by the parent gender being male (OR 1.50; 95% CI 1.09, 2.05), non‐Chinese (OR 1.75%; 95% CI 1.10, 2.79), and those who preferred child specialists (OR 2.02; 95% CI 1.27, 3.23). Lower income group (OR 4.28; 95% CI 2.30, 7.95) and not having a regular doctor (OR 4.99%; 95% CI 3.19, 7.80) were predictors of using the public health services.Conclusions:  Parent's gender, ethnicity and income influenced their decision to seek early medical consultation for their children's respiratory illness while income and having a regular doctor could predict their choice of healthcare services.
Accuracy of pulse oximetry in assessing heart rate of infants in the neonatal intensive care unit
Authors: Singh Jasbir KSB , Kamlin C Omar F , Morley Colin J , O'Donnell Colm PF , Donath Susan M , Davis Peter G 
Published: November 2007

Aim:  To determine the accuracy of pulse oximetry measurement of heart rate in the neonatal intensive care unit.Methods:  Stable preterm infants were monitored with a pulse oximeter and an ECG. The displays of both monitors were captured on video. Heart rate data from both monitors, including measures of signal quality, were extracted and analysed using Bland Altman plots.Results:  In 30 infants the mean (SD) difference between heart rate measured by pulse oximetry and electrocardiography was −0.4 (12) beats per minute. Accuracy was maintained when the signal quality or perfusion was low.Conclusion:  Pulse oximetry may provide a useful measurement of heart rate in the neonatal intensive care unit. Studies of this technique in the delivery room are indicated.
Rates of early intervention services in very preterm children with developmental disabilities at age 2 years
Authors: Roberts Gehan , Howard Kelly , Spittle Alicia J , Brown Nisha C , Anderson Peter J , Doyle Lex W 
Published: November 2007

Aim: Preterm birth is increasing in prevalence and long‐term follow‐up studies have documented high rates of neurosensory, intellectual, academic and behavioural disabilities. The importance of early intervention (EI) is well recognised but significant barriers to receiving EI exist in the community. This study explores the association of levels of disability at age 2 years with EI services and social risk in a large cohort of very preterm children.Methods: This was a cohort study of 236 very preterm (gestational age < 30 weeks or birthweight < 1250 g) infants recruited at birth. Children were assessed comprehensively at age 2 years, and EI and social risk data were gathered via parental questionnaire. Disability levels were assigned as none, mild, or moderate to severe. The relationships of disability level to EI services and social risk were determined.Results: Of the initial cohort, data from 227 (97%) were available at age 2 years. Overall, 50.7% (115/227) of children had some disability. A significant difference was present (P < 0.001) between the rates of EI and disability, with only 27.9% of children with a mild disability receiving EI services compared with 51.1% of children with a moderate to severe disability. After adjustment for level of disability, those of higher social risk were less likely to receive EI services (odds ratio 0.25; 95% confidence interval 0.11–0.56;P = 001).Conclusions: Currently available follow‐up, referral and EI services underserve the most vulnerable children in our community, those with a combination of biological and social risk factors for developmental disabilities.
Full breastfeeding and paediatric cancer
Authors: Ortega‐García Juan A , Ferrís‐Tortajada Josep , Torres‐Cantero Alberto M , Soldin Offie P , Torres Encarna Pastor , Fuster‐Soler Jose L , Lopez‐Ibor Blanca , Madero‐López Luis 
Published: November 2007

Aim:  It has been suggested that there is an inverse association between breastfeeding and the risk of childhood cancer. We investigated the association between full breastfeeding and paediatric cancer (PC) in a case control study in Spain.Methods:  Maternal reports of full breastfeeding, collected through personal interviews using the Paediatric Environmental History, were compared among 187 children 6 months of age or older who had PC and 187 age‐matched control siblings.Results:  The mean duration of full breastfeeding for cases were 8.43 and 11.25 weeks for controls. Cases had been significantly more often bottle‐fed than controls (odds ratio (OR) 1.8; 95% confidence interval (CI) 1.1–2.8). Cases were significantly less breastfed for at least 2 months (OR 0.5; 95% CI 0.3–0.8), for at least 4 months (OR 0.5; 95% CI 0.3–0.8), and for 24 weeks or more (OR 0.5; 95% CI 0.2–0.9).Conclusions:  Breastfeeding was inversely associated with PC, the protection increasing with the duration of full breastfeeding. Additional research on possible mechanisms of this association may be warranted. Meanwhile, breastfeeding should be encouraged among mothers.