bluuebunny/crossref_metadata_2025 huggingface dataset:
Neuromuscular function and balance of prepubertal and pubertal blind and sighted boys
Authors: Häkkinen Arja , Holopainen Elina , Kautiainen Hannu , Sillanpää Elina , Häkkinen Keijo
Published: March 2006

Aim: To compare the neuromuscular function and balance of blind prepuberty‐ and puberty‐aged boys to those with normal sight. Methods: Thirty‐three prepubertal (aged 9–13 y) and pubertal (aged 15–18 y) blind and sighted boys were tested for muscle mass thickness, electromyography and maximal isometric strength, dynamic explosive actions, and balance. Results: There was no difference in the muscle mass thickness, maximal strength or vertical jump between the blind and sighted boys. However, fitness‐ball throwing and five‐jump distances were significantly shorter in both blind groups compared to the sighted groups. One‐leg stance of the prepuberty‐aged sighted boys was 109 (67) s and in blind boys 32 (12) s, and in the puberty‐aged boys 120 (57) s and 31 (8) s, respectively. When vision was blocked in the sighted boys, differences between the blind and sighted boys disappeared.

Conclusion: The results showed comparable performance between prepubertal and pubertal blind and sighted boys in the static physical fitness tests. However, balance and performance in dynamic multi‐joint tests did not improve similarly in the blind groups compared to sighted groups, indicating that maturation, learning and experience by themselves cannot compensate for the loss of sight.
Selectin polymorphisms and perinatal morbidity in low‐birthweight infants
Authors: Derzbach László , Bokodi Géza , Treszl András , Vásárhelyi Barna , Nobilis Andras , Rigó János
Published: March 2006

Abstracts

Background: Studies have shown an association between altered expression of selectins and premature birth, early sepsis and bronchopulmonary dysplasia. Aim: To investigate the possible link between functional polymorphisms of the E‐, P‐ and L‐selectin genes and perinatal morbidity. Methods: We compared the genotype distribution of the E‐selectin Ser128Arg, P‐selectin Thr715Pro and L‐selectin Pro213Ser polymorphisms in 125 low‐birthweight singleton infants with those of 156 healthy term neonates. We also analysed the association of genotype with risk of sepsis and bronchopulmonary dysplasia. Results: We found no association between E‐selectin or P‐selectin polymorphisms and premature birth, nor did we find any association between E‐selectin or P‐selectin and early postnatal sepsis or bronchopulmonary dysplasia. Carriers of the 213Ser L‐selectin allele were found to be more prevalent in low‐birthweight infants, particularly in those with bronchopulmonary dysplasia. We found no association between the L‐selectin polymorphism and early postnatal sepsis.

Conclusion: Our results underline the importance of L‐selectin in perinatal pathology, but further studies are needed to evaluate the alteration of L‐selectin levels in carriers of the 213Ser allele and their possible contribution to premature birth and bronchopulmonary dysplasia.
Systemic levels following PGE1 inhalation in neonatal hypoxemic respiratory failure
Authors: Sood Beena G. , Glibetic Maria , Aranda Jacob V. , Delaney‐Black Virginia , Chen Xinguang , Shankaran Seetha
Published: March 2006

Aim: To measure plasma prostaglandin E1 (PGE1) levels in newborns with hypoxemic respiratory failure (NHRF) following inhaled PGE1 (IPGE1), normal term newborns, and newborns with congenital heart disease (CHD) following intravenous PGE1. Methods: Twenty newborns with NHRF received IPGE1 by jet nebulizer in doses of 25, 50, 150, and 300 ng/kg/min followed by weaning. Blood for PGE1 assay using enzyme immunoassay was available in eight neonates with NHRF, 10 normal newborns, and three neonates with CHD. Results: There were no differences in PGE1 levels between cord arterial blood in normal newborns and baseline samples from newborns with NHRF. Oxygenation improved significantly following IPGE1 (p=0.024) in newborns with NHRF. No adverse events were identified. Although a reversible increase in PGE1 levels was detected following a dose of 50 ng/kg/min (p <0.05), there was no association between PGE1 levels and IPGE1 duration, Pa O2, temperature, heart rate, and blood pressure.

Conclusion: A reversible increase in mean PGE1 levels was demonstrable at low doses of IPGE1 in babies with NHRF using a sensitive assay, suggesting effective drug delivery. Levels did not increase further with increasing dose or duration of administration, suggesting local action in the lungs and a lack of systemic spillover due to extensive pulmonary metabolism offering pulmonary selectivity.
Sex influences on lung function and medication in childhood asthma
Authors: Hallberg Jenny , Anderson Martin , Wickman Magnus , Svartengren Magnus
Published: March 2006

Aim: To evaluate possible sex differences in prevalence, diagnosis and treatment of asthma, and influence on lung function associated with asthma severity in a population‐based birth cohort (BAMSE) of 4089 children. Methods: At 4‐y follow‐up, 92% responded to a questionnaire on symptoms of asthma, current medication and doctor's diagnosis of asthma. A total of 2965 children participated in clinical testing, including measurements of peak expiratory flow (PEF), and were assigned to groups of asthma or no asthma by reported airway symptoms. Results: Children in asthma groups had lower PEF readings compared to healthy children. This effect was most pronounced for both sexes in the persistent group (boys p<0.05, girls p<0.001) and for girls in the transient group (p<0.01). A doctor's diagnosis of asthma did not significantly differ between boys and girls, but significantly more boys than girls had inhaled corticosteroids, even when stratifying by frequency of symptoms.

Conclusion: These results suggest that when 4‐y‐old children are stratified according to common diagnostic criteria, girls have a larger effect on PEF of asthma symptoms and are less frequently treated compared to boys.
Spontaneous localized intestinal perforation and intestinal dilatation in very‐low‐birthweight infants
Authors: Koshinaga Tsugumichi , Gotoh Hiroshi , Sugito Kiminobu , Ikeda Tarou , Hagiwara Noritsugu , Tomita Ryouichi
Published: March 2006

Aim: To elucidate how spontaneous localized intestinal perforation (SLIP) is related to intestinal morphological features such as dilatation in very‐low‐birthweight (VLBW) infants. Methods: The medical records of 13 VLBW infants (<1500 g) undergoing laparotomy between 1983 and 2003 for presumed SLIP were retrospectively reviewed. Clinical findings including maternal, prenatal and perinatal factors were analysed, and the clinical and surgical findings upon laparotomy were compared. Results: Postnatal pathological conditions included patent ductus arteriosus (n= 7), sepsis (n= 2), respiratory distress syndrome (n= 7), intraventricular haemorrhage (n= 2), an indwelling catheter via the umbilical vein (n= 1) and pneumonia (n= 1). Indomethacin was used in seven neonates with patent ductus arteriosus, and dexamethasone preventive therapy was employed in one neonate for bronchopulmonary dysplasia. Operative findings revealed a localized small punched‐out perforation in the ileum. Five patients had intestinal dilatation: two with a perforation in the middle of the dilated intestine, and three with a perforation proximal to the region of dilatation. The muscularis propria was absent in the dilated intestine of four patients.

Conclusion: This study found no significant relationship between perforation and dilatation of the intestine. Perforation may occur in any portion of the ischaemic intestine when circulatory failure becomes severe, and is not necessarily restricted to the dilated intestine. We believe that SLIP and intestinal dilatation may occur on the same basis in low‐birthweight infants; however, the disease process may be aetiologically different.
The NHE3 Juxtamembrane Cytoplasmic Domain Directly Binds Ezrin: Dual Role in NHE3 Trafficking and Mobility in the Brush Border
Authors: Cha Boyoung , Tse Ming , Yun Chris , Kovbasnjuk Olga , Mohan Sachin , Hubbard Ann , Arpin Monique , Donowitz Mark
Published: March 2006

Based on physiological studies, the epithelial brush-border (BB) Na+/H+antiporter3 (NHE3) seems to associate with the actin cytoskeleton both by binding to and independently of the PDZ domain containing proteins NHERF1 and NHERF2. We now show that NHE3 directly binds ezrin at a site in its C terminus between aa 475-589, which is separate from the PSD95/dlg/zonular occludens-1 (PDZ) interacting domain. This is an area predicted to be α-helical, with a positive aa cluster on one side (K516, R520, and R527). Point mutations of these positively charged aa reduced (NHE3 double mutant [R520F, R527F]) or abolished (NHE3 triple mutant [K516Q, R520F, R 527F]) ezrin binding. Functional consequences of these NHE3 point mutants included the following. 1) A marked decrease in surface amount with a greater decrease in NHE3 activity. 2) Decreased surface expression due to decreased rates of exocytosis and plasma membrane delivery of newly synthesized NHE3, with normal total expression levels and slightly reduced endocytosis rates. 3) A longer plasma membrane half-life of mutant NHE3 with normal total half-life. 4) Decreased BB mobile fraction of NHE3 double mutant. These results show that NHE3 binds ezrin directly as well as indirectly and suggest that the former is related to 1) the exocytic trafficking of and plasma membrane delivery of newly synthesized NHE3, which determines the amount of plasma membrane NHE3 and partially determines NHE3 activity, and 2) BB mobility of NHE3, which may increase its delivery from microvilli to the intervillus clefts, perhaps for NHE3-regulated endocytosis.
Compartmentation of the Nucleolar Processing Proteins in the Granular Component Is a CK2-driven Process
Authors: Louvet Emilie , Junéra Henriette Roberte , Berthuy Isabelle , Hernandez-Verdun Danièle
Published: March 2006

To analyze the compartmentation of nucleolar protein complexes, the mechanisms controlling targeting of nucleolar processing proteins onto rRNA transcription sites has been investigated. We studied the reversible disconnection of transcripts and processing proteins using digitonin-permeabilized cells in assays capable of promoting nucleolar reorganization. The assays show that the dynamics of nucleolar reformation is ATP/GTP-dependent, sensitive to temperature, and CK2-driven. We further demonstrate the role of CK2 on the rRNA-processing protein B23. Mutation of the major CK2 site on B23 induces reorganization of nucleolar components that separate from each other. This was confirmed in assays using extracts containing B23 mutated in the CK2-binding sites. We propose that phosphorylation controls the compartmentation of the rRNA-processing proteins and that CK2 is involved in this process.
Early experience and parent-of-origin-specific effects influence female reproductive success in mice
Authors: Hager Reinmar , Johnstone Rufus A
Published: March 2006

Recent studies on mammals investigating parent-of-origin-specific effects such as genomic imprinting and maternal effects have demonstrated their impact on short-term measures of fitness, for example offspring growth. However, the long-term fitness consequences of parent-of-origin-specific effects and their role outside the immediate mother–offspring interaction remain largely unexplored. Here, we show that female mice mated to males that inherited the same set of paternal and maternal genes as themselves have a higher reproductive success than females mated to males of reciprocal genotype. Furthermore, we demonstrate that the early social environment experienced by an individual influences its reproductive success. Females raised with unrelated siblings in a mixed litter had a subsequent lower reproductive success than those that were fostered together with all their biological siblings in unmixed litters. Our results highlight the important influence of parent-of-origin-specific effects and conditions in early development on long-term reproductive success in mammals and suggest that parent-of-origin-specific effects may provide the underlying mechanism for beneficial coadaptation between genotypes, for example, in mate choice.
Infanticide by subordinates influences reproductive sharing in cooperatively breeding meerkats
Authors: Young Andrew J , Clutton-Brock Tim
Published: March 2006

In cooperative animal societies, dominant females typically show higher breeding success than subordinates, and are commonly believed to control the extent of reproductive sharing. However, studies of social insect societies reveal that subordinates too can interfere with the breeding attempts of others, with important implications for the distribution of fitness within colonies. Here, we show that subordinate females in a high-skew vertebrate (the meerkat,
Suricata suricatta
), also exert a substantial influence over the reproductive attempts of others. In meerkat societies, pregnant dominants are known to kill subordinate litters, but we show that pregnant subordinates also kill pups; not only those of other subordinates but the dominant's as well. Litters born to females of any rank were half as likely to survive their first 4 days if a subordinate was pregnant. However, dominant females were more likely than subordinates to give birth when no other females were pregnant, and so lost fewer litters to infanticide than subordinates. This is probably due in part to dominants employing counter-tactics to reduce the incidence of subordinate pregnancy. We discuss the broad implications of subordinates having a degree of control over reproductive sharing for future attempts to understand the distribution of reproduction in animal societies.
Monitoring of metabolite gradients in tissue-engineered constructs
Authors: Boubriak Olga A , Urban Jill P.G , Cui Zhanfeng
Published: March 2006

At present, the assessment of developing tissue-engineered constructs is almost always carried out destructively using biochemical or histological methods to determine cell number, viability and tissue growth throughout the construct. Since many of these experiments are long, taking weeks or even months to complete, simple and readily applicable non-destructive methods of monitoring changes in cell metabolism, viability and tissue deposition within the construct would be invaluable; such methods could point out adverse responses during the early stages of culture. Here, we describe the use of microdialysis for detecting local changes in cellular metabolism within a tissue-engineered construct. Three-dimensional constructs consisting of bovine articular chondrocytes entrapped in an alginate gel were cultured in a bioreactor for two weeks. Glucose and lactate were monitored by microdialysis, as the major nutrient and metabolite, respectively. Concentration gradients within the construct were evident, with the highest lactate concentrations in the construct centre. The local lactate concentration was a measure of cellular metabolic activity, decreasing as cellular activity fell and increasing as cellular activity was stimulated. Nutrient starvation and cell death in the construct centre could be readily detected in constructs deliberately cultured under adverse conditions. The results show that probe measurements can give an early warning of inappropriate local metabolic changes. Such information during the growth of tissue-engineered constructs would allow either corrective action or else an early end to an unsuccessful test.
A qualitative approach to quantum probability
Authors: Lehrer Ehud , Shmaya Eran
Published: March 2006

A likelihood order is defined over linear subspaces of a finite dimensional Hilbert space. The question arises as to when such an order can be represented by a quantum probability. We introduce a few behaviorally plausible axioms that provide the answer in two cases: pure state and uniform measure. The general problem is answered by using duality-like conditions.

The general problem of characterizing the partial orders that admit a quantum representation by behaviorally justified axioms remains open.
An asymptotic analysis of initial-value problems for thin elastic plates
Authors: Kaplunov Julius , Nolde Evgeniya , Rogerson Graham A
Published: March 2006

An asymptotic technique is developed to analyse initial-value problems in application to the three-dimensional theory of thin elastic plates. Various sets of long-wave initial data are considered, with arbitrary distribution along the plate thickness. To account for the initial data, composite asymptotic expansions are employed, utilizing both two-dimensional low-frequency and high-frequency models. The former correspond to the classical theories of plate bending and extension, and their refinements, whereas the latter are associated with the long-wave motions occurring in the vicinities of thickness stretch and shear resonance frequencies. Six cases of iteration process are revealed depending on the symmetry of the initial data and their thickness variation. For each case, approximate two-dimensional initial conditions are derived, including higher-order corrections for the two-dimensional low-frequency refined plate theories. The validity of the proposed approach is justified by comparison with the exact solution of the model plane problem for initial data with uniform distribution along the thickness and sinusoidal distribution along the mid-plane. The methodology of the paper has potential for more general initial-value problems specified over a narrow domain, including many of those commonly met in physical applied mathematics.
Separate attentional resources for vision and audition
Authors: Alais David , Morrone Concetta , Burr David
Published: March 2006

Current models of attention, typically claim that vision and audition are limited by a common attentional resource which means that visual performance should be adversely affected by a concurrent auditory task and vice versa. Here, we test this implication by measuring auditory (pitch) and visual (contrast) thresholds in conjunction with cross-modal secondary tasks and find that no such interference occurs. Visual contrast discrimination thresholds were unaffected by a concurrent chord or pitch discrimination, and pitch-discrimination thresholds were virtually unaffected by a concurrent visual search or contrast discrimination task. However, if the dual tasks were presented within the same modality, thresholds were raised by a factor of between two (for visual discrimination) and four (for auditory discrimination). These results suggest that at least for low-level tasks such as discriminations of pitch and contrast, each sensory modality is under separate attentional control, rather than being limited by a supramodal attentional resource. This has implications for current theories of attention as well as for the use of multi-sensory media for efficient informational transmission.
AWolbachia-associated fitness benefit depends on genetic background inDrosophila simulans
Authors: Dean Matthew D
Published: March 2006

The α-proteobacteriaWolbachiainfect a number of insect species and influence host reproduction to favour the spread of infected females through a population. The fitness effect of this infection is important in understanding the spread and maintenance ofWolbachiawithin and among host populations. However, a full elucidation of fitness effect requires careful control of host genetic background. Here, I transferred a single clone ofWolbachia(thewHa strain) into three genetically distinct isofemale lines of the flyDrosophila simulansusing microinjection methodology. These lines carried one of the three described mitochondrial haplogroups (siI,siII orsiIII) and differ in nuclear genome as well. Population cage assays showed thatwHa-infectedsiIII flies enjoyed a dramatic fitness benefit compared to uninfectedsiIII. In contrast,wHa did not affect the fitness ofsiI orsiII flies. This study points to the importance of host-by-symbiont interaction terms that may play an important role in organismal-fitness.
Kittiwakes strategically reduce investment in replacement clutches
Authors: Gasparini Julien , Roulin Alexandre , Gill Verena A , Hatch Scott A , Boulinier Thierry
Published: March 2006

Many life-history traits are expressed interactively in life, but to a varying extent on different occasions. Changes in trait expression can be accounted for by differences in the quality of the environment (‘environmental constraint’ hypothesis) or by strategic adjustments, if the relative contribution of the trait to fitness varies with time (‘strategic allocation’ hypothesis). In birds, egg production is lower in replacement clutches than in first clutches, but it is unknown whether this reduction results from an environmental constraint (e.g. food being less available at the time when the replacement clutch is produced) or from a strategic allocation of resources between the two breeding attempts. To distinguish between these two hypotheses, we performed an experiment with black-legged kittiwakes (
Rissa tridactyla
). Pairs were either food-supplemented or not before the first clutch was laid onwards and we induced them to produce a replacement clutch by removing eggs once when the first clutch was complete. As predicted by the ‘strategic allocation’ hypothesis, egg production of food-supplemented and non-food-supplemented birds decreased between first and replacement clutches. This suggests that kittiwakes strategically reduce investment in egg production for their replacement clutches compared to first clutches.
Emergence of gynodioecy in wild beet (Beta vulgarisssp.maritimaL.): a genealogical approach using chloroplastic nucleotide sequences
Authors: Fénart Stéphane , Touzet Pascal , Arnaud Jean-François , Cuguen Joël
Published: March 2006

Gynodioecy is a breeding system where both hermaphroditic and female individuals coexist within plant populations. This dimorphism is the result of a genomic interaction between maternally inherited cytoplasmic male sterility (CMS) genes and bi-parentally inherited nuclear male fertility restorers. As opposed to other gynodioecious species, where every cytoplasm seems to be associated with male sterility, wild beetBeta vulgarisssp.maritimaexhibits a minority of sterilizing cytoplasms among numerous non-sterilizing ones. Many studies on population genetics have explored the molecular diversity of different CMS cytoplasms, but questions remain concerning their evolutionary dynamics. In this paper we report one of the first investigations on phylogenetic relationships between CMS and non-CMS lineages. We investigated the phylogenetic relationships between 35 individuals exhibiting different mitochondrial haplotypes. Relying on the high linkage disequilibrium between chloroplastic and mitochondrial genomes, we chose to analyse the nucleotide sequence diversity of three chloroplastic fragments (trnKintron,trnD–trnTandtrnL–trnFintergenic spacers). Nucleotide diversity appeared to be low, suggesting a recent bottleneck during the evolutionary history ofB. vulgarisssp.maritima. Statistical parsimony analyses revealed a star-like genealogy and showed that sterilizing haplotypes all belong to different lineages derived from an ancestral non-sterilizing cytoplasm. These results suggest a rapid evolution of male sterility in this taxon. The emergence of gynodioecy in wild beet is confronted with theoretical expectations, describing either gynodioecy dynamics as the maintenance of CMS factors through balancing selection or as a constant turnover of new CMSs.
‘Trans-generational immune priming’: specific enhancement of the antimicrobial immune response in the mealworm beetle,Tenebrio molitor
Authors: Moret Yannick
Published: March 2006

Encounters with parasites and pathogens are often unpredictable in time. However, experience of an infection may provide the host with reliable cues about the future risk of infection for the host itself or for its progeny. If the parental environment predicts the quality of the progeny's environment, then parents may further enhance their net reproductive success by differentially providing their offspring with phenotypes to cope with potential hazards such as pathogen infection. Here, I test for the occurrence of such an adaptive transgenerational phenotypic plasticity in the mealworm beetle,Tenebrio molitor. A pathogenic environment was mimicked by injection of bacterial lipopolysaccharides for two generations of insects. I found that parental challenge enhanced offspring immunity through the inducible production of antimicrobial peptides in the haemolymph.
Explaining the explosion: modelling hybrid invasions
Authors: Hall Richard J , Hastings Alan , Ayres Debra R
Published: March 2006

The emergence of hybrids between native and introduced species is an increasingly widespread problem which can alter entire ecosystems. We present a general model for the hybridization of two plant species to investigate the conditions under which hybrid invasions can occur, and the ecological and genetic consequences of such hybridizations. We find that parental compatibility and fecundity are important determinants of whether (and at what rate) hybrid genotypes emerge. Enhanced hybrid fitness traits affect both the population's genetic structure and total rate of increase, with rapid selection for the fittest genotype. Conversely, if different genotypes maximize different life-history characteristics, the ensuing population can be genetically very variable. The model provides a novel approach to evaluate the contributions of population dynamic and genetic processes in the study of hybrid invasions.
Maternal food provisioning in relation to condition-dependent offspring odours in burrower bugs (Sehirus cinctus)
Authors: Kölliker Mathias , Chuckalovcak John P , Haynes Kenneth F , Brodie Edmund D
Published: March 2006

The sensory modalities used for communication among family members have at least partly evolved within an organism's pre-existing sensory context. Given the well-known general importance of chemical communication in insects, we hypothesized in sub-social insects with parental care that chemical signals emitted by larvae to influence parental care (i.e. solicitation pheromones) would have evolved. To test this hypothesis, we performed an experiment in the burrower bugSehirus cinctus(Hemiptera: Cydnidae) where nymphs were hand-reared under high- or low-food conditions. These hand-reared clutches were used as a source of volatiles. The volatiles were collected for chemical analysis and delivered to caring mothers to quantify their behavioural response. As predicted, mothers exposed to volatiles from nymphs in poor condition provisioned significantly more food than those exposed to air (controls) or volatiles from high-condition nymphs. Chemical analysis revealed that nymphs emitted a blend of eight compounds of which α-pinene and camphene showed the strongest relationship with food treatment. Exposure to pure synthetic α-pinene and camphene did not affect maternal provisioning, however, suggesting that the functional significance of α-pinene and/or camphene may occur in a blend with other compounds. This study shows a clear effect of condition-dependent offspring odours on maternal food provisioning and identifies, for the first time, candidate compounds for a potential chemical offspring begging signal.
Evolution in group-structured populations can resolve the tragedy of the commons
Authors: Killingback Timothy , Bieri Jonas , Flatt Thomas
Published: March 2006

Public goods are the key features of all human societies and are also important in many animal societies. Collaborative hunting and collective defence are but two examples of public goods that have played a crucial role in the development of human societies and still play an important role in many animal societies. Public goods allow societies composed largely of cooperators to outperform societies composed mainly of non-cooperators. However, public goods also provide an incentive for individuals to be selfish by benefiting from the public good without contributing to it. This is the essential paradox of cooperation—known variously as the Tragedy of the Commons, Multi-person Prisoner's Dilemma or Social Dilemma. Here, we show that a new model for evolution in group-structured populations provides a simple and effective mechanism for the emergence and maintenance of cooperation in such a social dilemma. This model does not depend on kin selection, direct or indirect reciprocity, punishment, optional participation or trait-group selection. Since this mechanism depends only on population dynamics and requires no cognitive abilities on the part of the agents concerned, it potentially applies to organisms at all levels of complexity.
Experimentally increased food resources in the natal territory promote offspring philopatry and helping in cooperatively breeding carrion crows
Authors: Baglione Vittorio , Canestrari Daniela , Marcos José M , Ekman Jan
Published: March 2006

Kin-based societies, where families represent the basic social unit, occur in a relatively small number of vertebrate species. In the majority of avian kin societies, families form when offspring prolong their association with the parents on the natal territory. Therefore, the key to understanding the evolution of families in birds is to understand natal philopatry (i.e. the tendency to remain on the natal territory). It has been shown that, within populations, the strength of the association between parents and offspring (i.e. family stability) increases when offspring dispersal is constrained by external environmental factors, but it is unclear whether and how family wealth influences juvenile dispersal decisions. Here, we show that young carrion crows (
Corvus corone corone
) from territories that were food-supplemented year-round were more philopatric and more likely to help at their family's nest than the unfed ones. The results suggest that offspring philopatry and helping behaviour are influenced by the quality of ‘home’ and that the availability of food resources positively affects the cohesion of the family.
Lifetime reproductive success and density-dependent, multi-variable resource selection
Authors: McLoughlin Philip D , Boyce Mark S , Coulson Tim , Clutton-Brock Tim
Published: March 2006

Individuals are predicted to maximize lifetime reproductive success (LRS) through selective use of resources; however, a wide range of ecological and social processes may prevent individuals from always using the highest-quality resources available. Resource selection functions (RSFs) estimate the relative amount of time an individual spends using a resource as a function of the proportional availability of that resource. We quantified the association between LRS and coefficients of individual-based RSFs describing lifetime resource selection for 267 female red deer (Cervus elaphus) of the Isle of Rum, Scotland, from 1970 to 2001. LRS was significantly related to first- and second-order effects of selection forAgrostis/Festucagrassland and proximity to the sea coast (quality of forage withinAgrostis/Festucagrassland was highest nearest the coast (ratio of short : long grassland)). The benefits of selecting for quality inAgrostis/Festucagrassland, however, traded-off with increases in LRS gained by avoiding conspecific density. LRS was inversely associated with local density, which was highest along the coast, and reproductive benefits of selectingAgrostis/Festucagrassland diminished with increasing density. We discuss the relevance of these results to our understanding of the spatial distribution of red deer abundance, and potential applications of our approach to evolutionary and applied ecology.
Comparative analyses of the influence of developmental mode on phenotypic diversification rates in shorebirds
Authors: Thomas Gavin H , Freckleton Robert P , Székely Tamás
Published: March 2006

Phenotypic diversity is not evenly distributed across lineages. Here, we describe and apply a maximum-likelihood phylogenetic comparative method to test for different rates of phenotypic evolution between groups of the avian order Charadriiformes (shorebirds, gulls and alcids) to test the influence of a binary trait (offspring demand; semi-precocial or precocial) on rates of evolution of parental care, mating systems and secondary sexual traits. In semi-precocial species, chicks are reliant on the parents for feeding, but in precocial species the chicks feed themselves. Thus, where the parents are emancipated from feeding the young, we predict that there is an increased potential for brood desertion, and consequently for the divergence of mating systems. In addition, secondary sexual traits are predicted to evolve faster in groups with less demanding young. We found that precocial development not only allows rapid divergence of parental care and mating behaviours, but also promotes the rapid diversification of secondary sexual characters, most notably sexual size dimorphism (SSD) in body mass. Thus, less demanding offspring appear to facilitate rapid evolution of breeding systems and some sexually selected traits.
Active use of the metapleural glands by ants in controlling fungal infection
Authors: Fernández-Marín Hermógenes , Zimmerman Jess K , Rehner Stephen A , Wcislo William T
Published: March 2006

Insect societies face constant challenges from disease agents. Ants deploy diverse antimicrobial compounds against pathogens and the key sources are metapleural glands (MGs). Are MG products passively secreted and used indiscriminately or are they selectively used when ants are challenged by pathogens? In 26 species from five subfamilies, ants use foreleg movements to precisely groom the MG opening. In the absence of experimental infection, MG grooming rates are low and workers groom themselves after contacting the MGs. The derived leaf-cutter ants (AttaandAcromyrmex) also groom their fungal gardens, substrata (leaves), queens and nest-mates after MG grooming.Attarespond to a challenge by fungal conidia by increasing the rate of MG grooming, but do not do so when an inert powder is applied. This increase occurs in the first hour after a potential infection, after which it returns to baseline levels. Ants with open MGs produce more infrabuccal pellets (IP) than ants with sealed MGs and conidia within pellets from the former are less likely to germinate. Thus, ants selectively groom their MGs when disease agents are present, suggesting that they also selectively use their MG secretions, which has important implications for understanding the evolution of hygienic behaviour in social groups.
Real-time sea-level gauge observations and operational oceanography
Authors: Mourre Baptiste , Crosnier Laurence , Provost Christian Le
Published: March 2006

The contribution of tide-gauge data, which provide a unique monitoring of sea-level variability along the coasts of the world ocean, to operational oceanography is discussed in this paper. Two distinct applications that both demonstrate tide-gauge data utility when delivered in real-time are illustrated. The first case details basin-scale operational model validation of the French Mercator operational system applied to the North Atlantic. The accuracy of model outputs in the South Atlantic Bight both at coastal and offshore locations is evaluated using tide-gauge observations. These data enable one to assess the model's nowcasts and forecasts reliability which is needed in order for the model boundary conditions to be delivered to other coastal prediction systems. Such real-time validation is possible as long as data are delivered within a delay of a week. In the second application, tide-gauge data are assimilated in a storm surge model of the North Sea and used to control model trajectories in real-time. Using an advanced assimilation scheme that takes into account the swift evolution of model error statistics, these observations are shown to be very efficient to control model error, provided that they can be assimilated very frequently (i.e. available within a few hours).
Mean dynamic topography: intercomparisons and errors
Authors: Bingham Rory J , Haines Keith
Published: March 2006

Knowledge of the ocean dynamic topography, defined as the height of the sea surface above its rest-state (the geoid), would allow oceanographers to study the absolute circulation of the ocean and determine the associated geostrophic surface currents that help to regulate the Earth's climate. Here a novel approach to computing a mean dynamic topography (MDT), together with an error field, is presented for the northern North Atlantic. The method uses an ensemble of MDTs, each of which has been produced by the assimilation of hydrographic data into a numerical ocean model, to form a composite MDT, and uses the spread within the ensemble as a measure of the error on this MDT. The r.m.s. error for the composite MDT is 3.2 cm, and for the associated geostrophic currents the r.m.s. error is 2.5 cm s−1. Taylor diagrams are used to compare the composite MDT with several MDTs produced by a variety of alternative methods. Of these, the composite MDT is found to agree remarkably well with an MDT based on the GRACE geoid GGM01C. It is shown how the composite MDT and its error field are useful validation products against which other MDTs and their error fields can be compared.
Recent results on modelling the spatial and temporal structure of the Earth's gravity field
Authors: Moore P , Zhang Q , Alothman A
Published: March 2006

The Earth's gravity field plays a central role in sea-level change. In the simplest application a precise gravity field will enable oceanographers to capitalize fully on the altimetric datasets collected over the past decade or more by providing a geoid from which absolute sea-level topography can be recovered. However, the concept of a static gravity field is now redundant as we can observe temporal variability in the geoid due to mass redistribution in or on the total Earth system. Temporal variability, associated with interactions between the land, oceans and atmosphere, can be investigated through mass redistributions with, for example, flow of water from the land being balanced by an increase in ocean mass. Furthermore, as ocean transport is an important contributor to the mass redistribution the time varying gravity field can also be used to validate Global Ocean Circulation models.

This paper will review the recent history of static and temporal gravity field recovery, from the 1980s to the present day. In particular, mention will be made of the role of satellite laser ranging and other space tracking techniques, satellite altimetry andin situgravity which formed the basis of gravity field determination until the last few years. With the launch of Challenging Microsatellite Payload and Gravity and Circulation Experiment (GRACE) our knowledge of the spatial distribution of the Earth's gravity field is taking a leap forward. Furthermore, GRACE is now providing insight into temporal variability through ‘monthly’ gravity field solutions. Prior to this data we relied on satellite tracking, Global Positioning System and geophysical models to give us insight into the temporal variability. We will consider results from these methodologies and compare them to preliminary results from the GRACE mission.
Impacts of climate change on coastal flood risk in England and Wales: 2030–2100
Authors: Hall Jim W , Sayers Paul B , Walkden Mike J.A , Panzeri Mike
Published: March 2006

Coastal flood risk is a function of the probability of coastal flooding and the consequential damage. Scenarios of potential changes in coastal flood risk due to changes in climate, society and the economy over the twenty-first century have been analysed using a national-scale quantified flood risk analysis methodology. If it is assumed that there will be no adaptation to increasing coastal flood risk, the expected annual damage in England and Wales due to coastal flooding is predicted to increase from the current £0.5 billion to between £1.0 and £13.5 billion, depending on the scenario of climate and socio-economic change. The proportion of national flood risk that is attributable to coastal flooding is projected to increase from roughly 50% to between 60 and 70%. Scenarios of adaptation to increasing risk, by construction of coastal dikes or retreat from coastal floodplains, are analysed. These adaptations are shown to be able to reduce coastal flood risk to between £0.2 and £0.8 billion. The capital cost of the associated coastal engineering works is estimated to be between £12 and £40 billion. Non-structural measures to reduce risk can make a major contribution to reducing the cost and environmental impact of engineering measures.
Finding the molecular basis of complex genetic variation in humans and mice
Authors: Mott Richard
Published: March 2006

I survey the state of the art in complex trait analysis, including the use of new experimental and computational technologies and resources becoming available, and the challenges facing us. I also discuss how the prospects of rodent model systems compare with association mapping in humans.
From genomes to systems: the path with yeast
Authors: Oliver Stephen G
Published: March 2006

Metabolic Control Analysis (MCA) is a conceptual and mathematical formalism that models the relative contributions of individual effectors in a pathway to both the flux through the pathway and the concentrations of individual intermediates within it. To exploit MCA in an initial Systems Biology analysis of the eukaryotic cell, two categories of experiments are required. In category 1 experiments, flux is changed and the impact on the levels of the direct and indirect products of gene action is measured. We have measured the impact of changing the flux on the transcriptome, proteome and metabolome of
Saccharomyces cerevisiae
. In this whole-cell analysis, flux equates to growth rate. In category 2 experiments, the levels of individual gene products are altered, and the impact on the flux is measured. We have used competition analyses between the complete set of heterozygous yeast deletion mutants to reveal genes encoding proteins with high flux control coefficients. These genes may be exploited, in a top-down analysis, to build a coarse-grained model of the eukaryotic cell, as exemplified by yeast. More detailed modelling requires that ‘natural’ biological systems be identified. The combination of flux balance analysis with both genetics and metabolomics in the definition of metabolic systems is discussed.
Modelling in molecular biology: describing transcription regulatory networks at different scales
Authors: Schlitt Thomas , Brazma Alvis
Published: March 2006

Approaches to describe gene regulation networks can be categorized by increasing detail, as network parts lists, network topology models, network control logic models or dynamic models. We discuss the current state of the art for each of these approaches. We study the relationship between different topology models, and give examples how they can be used to infer functional annotations for genes of unknown function. We introduce a new simple way of describing dynamic models called finite state linear model (FSLM). We discuss the gap between the parts list and topology models on one hand, and network logic and dynamic models, on the other hand. The first two classes of models have reached a genome-wide scale, while for the other model classes high-throughput technologies are yet to make a major impact.
Adaptor protein Ste50p links the Ste11p MEKK to the HOG pathway through plasma membrane association
Authors: Wu Cunle , Jansen Gregor , Zhang Jianchun , Thomas David Y. , Whiteway Malcolm
Published: March 2006

In a variety of yeast cellular pathways, the Ste50p protein regulates the kinase function of the mitogen extracellular signal-regulated kinase kinase (MEKK) Ste11p. Both Ste11p and Ste50p contain sterile α motif (SAM) domains; these are interchangeable, and can be replaced by other protein-interacting modules. Furthermore, the function of the Ras association (RA)-like domain of Ste50p can be mimicked by a plasma membrane recruiting signal, and direct plasma membrane targeting of Ste11p bypasses the requirement of Ste50p for Ste11p function. Thus the regulatory role of Ste50p requires both the N-terminal SAM domain to bind Ste11p and the C-terminal RA-like domain to direct kinase localization. We have identified Opy2p, an integral membrane protein that can interact with Ste50p, as a new component in the Sho1p–Ste11p/Ste50p signaling branch of the high-osmolarity glycerol (HOG) pathway. We propose that Opy2p can serve as a membrane anchor for the Ste50p/Ste11p module in the activation of the HOG pathway.
Multipotential differentiation ability of GATA-1-null erythroid-committed cells
Authors: Kitajima Kenji , Zheng Jie , Yen Hilo , Sugiyama Daijiro , Nakano Toru
Published: March 2006

GATA-1, a zinc finger transcription factor, has been believed to be indispensable for the survival of proerythroblasts. However, we found that GATA-1-null proerythroblasts could survive and proliferate on OP9 stroma cells in the presence of erythropoietin. Furthermore, myeloid and mast cells were induced from the GATA-1-null proerythroblasts by the stimulation of granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-3 (IL-3), respectively, but lymphoid differentiation was not achieved by in vivo transfer. Thus, without activity of the transcription factor required for terminal differentiation, even relatively mature and committed cells proliferate continuously with the differentiation capacity to other lineages. Our data suggest that GATA-1 is a critical transcription factor to fix erythroid progenitors to the erythroid lineage.
The Saccharomyces cerevisiae histone H2A variant Htz1 is acetylated by NuA4
Authors: Keogh Michael-Christopher , Mennella Thomas A. , Sawa Chika , Berthelet Sharon , Krogan Nevan J. , Wolek Adam , Podolny Vladimir , Carpenter Laura Rocco , Greenblatt Jack F. , Baetz Kristin , Buratowski Stephen
Published: March 2006

The histone H2A variant H2A.Z (Saccharomyces cerevisiae Htz1) plays roles in transcription, DNA repair, chromosome stability, and limiting telomeric silencing. The Swr1-Complex (SWR-C) inserts Htz1 into chromatin and shares several subunits with the NuA4 histone acetyltransferase. Furthermore, mutants of these two complexes share several phenotypes, suggesting they may work together. Here we show that NuA4 acetylates Htz1 Lys 14 (K14) after the histone is assembled into chromatin by the SWR-C. K14 mutants exhibit specific defects in chromosome transmission without affecting transcription, telomeric silencing, or DNA repair. Function-specific modifications may help explain how the same component of chromatin can function in diverse pathways.
Smad3-dependent nuclear translocation of β-catenin is required for TGF-β1-induced proliferation of bone marrow-derived adult human mesenchymal stem cells
Authors: Jian Hongyan , Shen Xing , Liu Irwin. , Semenov Mikhail , He Xi , Wang Xiao-Fan
Published: March 2006

Adult mesenchymal stem cells (MSCs) derived from bone marrow contribute to the regeneration of multiple types of mesenchymal tissues. Here we describe the functional role of a novel form of cross-talk between the transforming growth factor β1 (TGF-β1) and Wnt signaling pathways in regulating the activities of human MSCs. We show that TGF-β1 induces rapid nuclear translocation of β-catenin in MSCs in a Smad3-dependent manner. Functionally, this pathway is required for the stimulation of MSC proliferation and the inhibition of MSC osteogenic differetiation by TGF-β1, likely through the regulation of specific downstream target genes. These results provide evidence for a new mode of cooperation between the TGF-β and Wnt signaling pathways in this specific cellular context and suggest a potentially important role for this distinct signaling pathway in the control of self-renewal and differentiation of a specific type of MSCs.