bluuebunny/crossref_metadata_2025_split huggingface dataset:
Strategies and counterstrategies to infanticide in mammals
Authors: EBENSPERGER LUIS A. 
Published: August 2010

ABSTRACTI analyse and summarize the empirical evidence in mammals supporting alternative benefits that individuals may accrue when committing nonparental infanticide. Nonparental infanticide may provide the perpetrator with nutritional benefits, increased access to limited resources, increased reproductive opportunities, or it may prevent misdirecting parental care to unrelated offspring. The possibility that infanticide is either a neutral or maladaptive behaviour also is considered. I devote the second half of this article to reviewing potential mechanisms that individuals may use to prevent infanticide. These counterstrategies include the early termination of pregnancy, direct aggression by the mother against intruders, the formation of coalitions for group defence, the avoidance of infanticidal conspecifics, female promiscuity, and territoriality. I evaluate the support for each benefit and counterstrategy across different groups of mammals and make suggestions for future research.
The effect of group size on mean food intake rate in birds
Authors: BEAUCHAMP GUY 
Published: August 2010

ABSTRACTA description of the relationship between mean food intake rate (MFIR) and group size is important in assessing the adaptiveness of group living in animals. Several hypotheses argue that foraging in groups can be beneficial in terms of MFIR but an overall assessment of the evidence available thus far was lacking. I examined this relationship in birds using studies that provided a measure of MFIR in groups of different sizes and evaluated the effect of study design and food type. In addition, I noted some of the mechanisms thought to be responsible for changes in MFIR with group size and quantified the impact of the addition of individual foragers. The most common pattern of change in MFIR with group size was a monotonic increase. The different patterns of change in MFIR with group size occurred with similar frequencies in experimental and observational studies despite the fact that observational studies often lacked control for confounding factors. Increases in MFIR were more likely to be associated with seeds as a food type than with fish or invertebrates, and were least likely with carcasses. This finding was related to the ease with which individuals can use aggression to increase their share of resources that are more concentrated in space. Adjustments in vigilance levels and aggression, as well as more subtle changes in speed of search and handling time, were correlated with changes in MFIR with group size. Finally, the addition of three to four individuals appeared to be needed to double the MFIR of a solitary bird. The results suggest that foraging in avian groups is often associated with increased MFIRs and that several ecological factors, including food dispersion, influence the pattern of change with group size.
A behavioural analysis of phase change in the desert locust
Authors: SIMPSON STEPHEN J. , McCAFFERY ALAN R. , HÄGELE BERND F. 
Published: August 2010

ABSTRACTA programme of research into phase change in the desert locust,Schistocerca gregaria, is described. The ability to change phase between solitarious and gregarious forms in response to population density is a key feature of locusts and is central to their occasional yet catastrophic impact on humans. Phase polymorphism is an extreme form of phenotypic plasticity. The most labile phase characteristic is behaviour. It is argued that a fully integrated study of behavioural phase change provides a powerful tool for understanding both the mechanisms of phase change and locust population dynamics, both of which offer possibilities for improved management and control of desert locust plagues. An assay for measuring behavioural phase‐state in individual locusts was derived, based on logistic regression analysis. Experiments are described that used the assay to quantify the time‐course of behavioural change, both within the life of individual locusts and across generations. The locust‐related stimuli that provoke behavioural gregarization were investigated. Complex interactions were found between tactile, visual and olfactory stimuli, with the former exerting the strongest effect. Behavioural analysis also directed a study of the mechanisms whereby adult females exert an epigenetic influence over the phase‐state of their developing offspring. Female locusts use their experience of the extent and recency of being crowded to predict the probability that their offspring will emerge into a high‐density population, and alter the development of their embryos accordingly through a gregarizing agent added to the foam that surrounds the eggs at laying. There is also a less pronounced paternal influence on hatchling phase‐state. An understanding of the time‐course of behavioural phase change led to a study of the effect of the fine‐scale distribution of resources in the environment on interactions between individual locusts, and hence on phase change. This, in turn, stimulated an exploration of the implications of individual behavioural phase change for population dynamics. Cellular automata models were derived that explore the relationships between population density, density of food resources and the distribution of resources in the environment. The results of the simulation showed how the extent of gregarization within a population increases with rising population size relative to food abundance and increasing concentration of food resources. Of particular interest was the emergence of critical zones across particular combinations of resource abundance, resource distribution and population size, where a solitarious population would rapidly gregarize. The model provided the basis for further laboratory and field experiments, which are described.
Ultraviolet radiation screening compounds
Authors: COCKELL CHARLES S. , KNOWLAND JOHN 
Published: August 2010

ABSTRACTAmongst the diversity of methods used by organisms to reduce damage caused by ultraviolet (UV) radiation, the synthesis of UV‐screening compounds is almost ubiquitous. UV‐screening compounds provide a passive method for the reduction of UV‐induced damage and they are widely distributed across the microbial, plant and animal kingdoms. They share some common chemical features. It is likely that on early earth strong selection pressures existed for the evolution of UV‐screening compounds. Many of these compounds probably had other physiological roles, later being selected for the efficacy of UV screening. The diversity in physiological functions is one of the complications in studying UV‐screening compounds and determining the true ecological importance of their UV‐screening role. As well as providing protection against ambient UV radiation, species with effective screening may also be at an advantage during natural ozone depletion events. In this review the characteristics of a wide diversity of UV‐screening compounds are discussed and evolutionary questions are explored. As research into the range of UV‐screening compounds represented in the biosphere continues, so it is likely that the properties of many more compounds will be elucidated. These compounds, as well as providing us with insights into natural responses to UV radiation, may also have implications for the development of artificial UV‐screening methods to reduce human exposure to UV radiation.
Genes and plant cell walls: a difficult relationship
Authors: WOJTASZEK PRZEMYSŁAW 
Published: August 2010

ABSTRACTChemical information, carried by genes, is one of several types of information important for the functioning of cells and organisms. While genes govern the two‐dimensional flow of information, the cell walls are at the basis of a structural, three‐dimensional framework of plant form and growth. Recent data show the walls to be a cellular'organelle’ undergoing dynamic changes in response to a plethora of stimuli. In this review, an integrated approach, rooted in the organismal perspective, is taken to consider the role of cell walls in the biology of plants. First, the complexity of molecular and biochemical events leading to the biosynthesis of wall components is described within the framework of its spatial cellular organisation, and the major regulatory check‐points are characterised. Second, cell walls form a structural and functional continuum within the whole plant and thus could be defined in relation to the protoplasts that produce them and in relation to the plant itself. Model systems of suspension‐cultured cells are used to reveal the existence of a bidirectional exchange of information between the protoplast and its walls. The ‘plasticity’ of plant cell reactions, seen in defence responses or in changes in wall composition, to e.g. stress, plant growth regulators or chemical agents as well as the role of cell walls and/or wall components in somatic embryogenesis are also discussed. Third, being a continuum within the plant body, the walls fulfil vital functions in plant growth and development. The examples characterised include the determination of cellular polarity and the plane of cell division, cytokinesis, and the role of plasmodesmata in cell‐to‐cell communication and the formation of functional symplastic domains. Fourth, the exocellular control of morphogenetic processes is described and the potential of cell walls as determinants or reservoirs of positional information is indicated. Particular emphasis is put on the (bio)chemical signals coming through or derived from cell walls as well as the mechanical properties of the walls. Based on those data, the ‘plant body’ concept is formulated. The plant is thus treated as a unit filled with intertwining networks: (1) symplastic, (2) the endomembrane system and (3) cytoskeletal, with cell walls providing an architectural scaffolding and communication ports formed within (4) the cytoskeleton‐plasma membrane‐cell wall continuum.
The social organization of fish shoals: a test of the predictive power of laboratory experiments for the field
Authors: KRAUSE JENS , BUTLIN ROGER K. , PEUHKURI NINA , PRITCHARD VICTORIA L. 
Published: August 2010

ABSTRACTBy contrast with a multitude of laboratory studies on the social organization of fish, relatively little is known about the size, composition and dynamics of free‐ranging fish shoals. We give an overview of the available information on fish shoals and assess to what degree the predictions made from laboratory studies are consistent with field data. The section on shoal choice behaviour in the laboratory is structured so that the evidence for different shoaling p is discussed in the context of their mechanisms and functions. Predictions based on experiments in captivity regarding p for conspecifics, individuals of similar body length and unparasitized fish were highly consistent with field observations on free‐ranging shoals whereas p for familiar conspecifics and kin remain to be conclusively demonstrated in the field. In general, there is a shortage of studies in which shoaling p have been investigated both in the laboratory and the field, and field studies have so far been largely descriptive revealing little about the underlying mechanisms of observed patterns. Given the great importance of fish shoals both in fundamental and applied research, an advancement of our knowledge of their social organization should significantly contribute to a better understanding of a whole range of topics including reciprocal altruism, group‐living and self‐organization.
Ethylene signal perception and transduction: multiple paradigms?
Authors: HALL M. A. , MOSHKOV I. E. , NOVIKOVA G. V. , MUR L. A. J. , SMITH A. R. 
Published: August 2010

ABSTRACTCurrent progress on the mechanisms of ethylene signal perception and transduction are reviewed with an emphasis on reconciling data from molecular genetics and from biochemical approaches. It is proposed that there exist two or more interacting transduction pathways.
Ossification patterns in the tetrapod limb – conservation and divergence from morphogenetic events
Authors: Fröbisch Nadia B. 
Published: August 2010

AbstractTwo different patterns of the condensation and chondrification of the limbs of tetrapods are known from extensive studies on their early skeletal development. These are on the one hand postaxial dominance in the sequential formation of skeletal elements in amniotes and anurans, and on the other, preaxial dominance in urodeles. The present study investigates the relative sequence of ossification in the fore‐ and hindlimbs of selected tetrapod taxa based on a literature survey in comparison to the patterns of early skeletal development, i.e. mesenchymal condensation and chondrification, representing essential steps in the late stages of tetrapod limb development. This reveals the degree of conservation and divergence of the ossification sequence from early morphogenetic events in the tetrapod limb skeleton. A step‐by‐step recapitulation of condensation and chondrification during the ossification of limbs can clearly be refuted. However, some of the deeper aspects of early skeletal patterning in the limbs, i.e. the general direction of development and sequence of digit formation are conserved, particularly in anamniotes. Amniotes show a weaker coupling of the ossification sequence in the limb skeleton with earlier condensation and chondrification events. The stronger correlation between the sequence of condensation/chondrification and ossification in the limbs of anamniotes may represent a plesiomorphic trait of tetrapods. The pattern of limb ossification across tetrapods also shows that some trends in the sequence of ossification of their limb skeleton are shared by major clades possibly representing phylogenetic signals.This review furthermore concerns the ossification sequence of the limbs of the Palaeozoic temnospondyl amphibian Apateon sp. For the first time this is described in detail and its patterns are compared with those observed in extant taxa. Apateon sp. shares preaxial dominance in limb development with extant salamanders and the specific order of ossification events in the fore‐ and hindlimb of this fossil dissorophoid is almost identical to that of some modern urodeles.
Does Biology Need an Organism Concept?
Authors: Pepper John W. , Herron Matthew D. 
Published: August 2010

AbstractAmong biologists, there is no general agreement on exactly what entities qualify as ‘organisms’. Instead, there are multiple competing organism concepts and definitions. While some authors think this is a problem that should be corrected, others have suggested that biology does not actually need an organism concept. We argue that the organism concept is central to biology and should not be abandoned. Both organism concepts and operational definitions are useful. We review criteria used for recognizing organisms and conclude that they are not categorical but rather continuously variable. Different organism concepts are useful for addressing different questions, and it is important to be explicit about which is being used. Finally, we examine the origins of the derived state of organismality, and suggest that it may result from positive feedback between natural selection and functional integration in biological entities.
Chromosome conformation capture of transcriptional interactions between cytochrome c oxidase genes and genes of glutamatergic synaptic transmission in neurons
Authors: Dhar Shilpa S. , Wong‐Riley Margaret T. T. 
Published: August 2010

J. Neurochem. (2010) 115, 676–683.AbstractNeuronal activity and energy metabolism are tightly coupled processes. Recently, we found that nuclear respiratory factor 1 co‐regulates all subunits of cytochrome c oxidase (COX, representing oxidative energy metabolism) and glutamatergic neurochemicals, including NR1 (Grin1) and NR2B (Grin2b) of NMDA receptors, GluR2 (Gria2) of alpha‐amino‐3‐hydroxy‐5‐methyl‐4‐isoxazolepropionic acid receptors, and neuronal nitric oxide synthase (Nos1). Moreover, all 10 nuclear‐encoded COX subunit genes and three transcription factor genes for the three mitochondrial‐encoded COX subunits are transcribed in the same transcription factory. The goal of the present study was to test our hypothesis that genomic loci for Grin1, Grin2b, Gria2, and Nos1 interact with those for COX at the transcriptional level. By means of chromosome conformation capture, interactions were found among all of these genes in neurons, but not in C2C12 muscle cells. COX subunit genes also did not interact with neurochemical genes not regulated by nuclear respiratory factor 1, nor with genes for calreticulin, a non‐mitochondrial protein. Depolarizing stimulation up‐regulated interaction frequencies between COX and neurochemical genes, whereas impulse blockade with tetrodotoxin or inhibition of COX with KCN down‐regulated them in neurons. Thus, an efficient mechanism is in place for coordinating the transcriptional coupling of energy metabolism and glutamatergic neurotransmission at the molecular level in neurons.
The Birth Was Normal — But is the Baby?
Authors: Phibbs Roderic H. 
Published: August 2010

ABSTRACT: The group of babies at lowest risk for neonatal problems have experienced a significant drop in morbidity and mortality since neonatology began in the 1960's. Up to 50% of such low‐risk babies develop jaundice which requires treatment. ABO hemolytic disease and polycythemia affect 5% and 3% of full‐term babies, respectively. Congenital malformations occur in about 1–2% of term newborns, and infection will be found in 2–5 babies per thousand. Because infections can be life‐threatening and the symptoms are vague in newborns, we do from 25 to 40 septic work‐ups for every one infection confirmed. Handling the high risk mother whose infant needs diagnostic or treatment procedures is easier than handling the shocked mother who expected a normal outcome according to Dr. Phibbs. It is better to give a simple statement of what is being done, and why, than to give technical explanations. Because of the adaptability of human mothers and infants, we find that separation of mothers and infants for common procedures does not interfere with bonding.
Is Neonatal Special Care Overused?
Authors: Richards M.P.M. 
Published: August 2010

ABSTRACT: Among the health regions of Britain, admissions to special care baby units (SCBUs) vary from 15% to 27% of live born children. These variations in admission rates do not correlate with the percentage of low birth‐weight babies born in each region, nor with the perinatal mortality rate. However, they correlate positively with the provision of cots for special newborn care and with how close the baby was to such a facility when born. A large number of full‐term babies are admitted with no disease, but simply for observation. These babies come predominately from deliveries in consultant obstetric units which also have SCBUs, so that admissions for observation are most probable for the group of babies receiving the highest standards of care and therefore are least in need of it. Some of the disadvantages of unnecessary admissions are described. A change in admission policy at one SCBU resulted in the number of full‐term babies admitted to SCBU dropping from 928 in 1972 to 163 in 1975. The effects of pressures to fill the cots in such units, of competition between units, and of other factors influencing admission are discussed.
The Economics of Intensive Care for the Full‐Term Newborn
Authors: Shearer Madeleine H. 
Published: August 2010

ABSTRACT: The nursery and labor/delivery unit have long been loss leaders in hospital accounting. However, Medicaid, Crippled (or Handicapped) Children's Services, Blue Cross and Blue Shield will make very high payments for intensive fetal and neonatal care. As a result, there was an increase of 18% in the number of neonatal intensive care units (NICUs) between 1977 and 1978, and a concomitant reduction in newborn nursery space. Because a large number of NICU beds, and a 75% occupancy rate, are required by local and professional standards, in order to fill NICU beds normal or very mildly sick full‐term newborns are being admitted. The number of tests and treatments were found to be lowest after rotation of residents in August, and to increase monthly until they rotated out in June. Of full‐term newborns, 18% were treated for jaundice and/or given septic work‐ups at one Level II hospital. At another, the same percent of babies was admitted to the NICU from the alternative birth center (ABC) as from the labor/delivery unit, despite figures indicating that the ABC babies had better outcomes on all parameters.
Episiotomy Counts: Trends and Prevalence in Canada, 1981/1982 to 1993/1994
Authors: Graham Ian D. , Graham Dawn Fowler 
Published: August 2010

Background: The purpose of this study was to produce a minimum estimate of the prevalence of episiotomy use in Canada, and to investigate the trend in its use between 1981/1982 and 1993/1994. Method: A retrospective population case series study was conducted using hospital discharge abstracts. Outcome measures were the count of episiotomies performed during a 12‐month period and the episiotomy rate per 100 vaginal births. Results: For more than a decade, official statistics have significantly underreported episiotomy use by as much as 50 percent. In 1993/1994 at least 37.7 percent of women giving birth vaginally in Canada are known to have received an episiotomy. Between 1981/1982 and 1993/1994 its prevalence declined 29.1 percent, with the greatest decline occurring during the 1990s. This decline did not result from changes in parity in the population. The decrease in episiotomy use during this 13‐year period is more than twice that found in the United States (a decline of only 13.6%). Conclusions: The reporting of official statistics on obstetric procedures in Canada should be modified to include all known cases of episiotomy. The observed downward trend in the rate of this procedure is encouraging, and is in the direction of evidence‐based recommendations advocating its restrictive use. (BIRTH 24:3, September 1997)
Reasons To Stay, Reasons To Go: Results of an Australian Population‐Based Survey
Authors: Brown Stephanie , Lumley Judith 
Published: August 2010

Background: Debate about early obstetric discharge is occurring simultaneously in several different countries. An Australian population‐based survey of recent mothers investigated women's views about shorter postnatal stays and assessed the impact of early discharge on important maternal health outcomes. Method: Women's views and experiences of length of hospital stay were gathered by means of a statewide postal survey of all women who gave birth in Victoria, Australia, during two weeks in 1993. Questionnaires were mailed to women 6 to 7 months after the birth; 62.5 percent (n = 1336) responded. Results: Most of the sample (64%) stayed in hospital for 5 or more days after the birth, 26.6 percent left on day 3 or 4, and 9.4 percent on day 1 or 2. Compared with women who stayed for 5 or more days, women who left in the first 48 hours were more likely to be multiparous; to have attended public models of care (public hospital clinic, shared care, public general practitioner, birth center); not to have private health insurance; to have experienced a lower level of obstetric intervention; and to have a very low income. Twenty‐one percent of women who left within 48 hours, and 26 percent of those who left on day 3 or 4 described their stay as too short. Women who left on day 3 or 4, or within 48 hours, were not more likely to experience any of the adverse outcomes investigated in the study: breastfeeding problems, low confidence about caring for the baby, or depression 6 to 7 months after birth. Women who left on day 3 or 4 had slightly lower rates of breastfeeding at 3 and 6 months than women staying for longer or shorter periods. Conclusion: Concerns about possible adverse outcomes resulting from shorter postnatal stays were not borne out by the study findings. Large and carefully designed randomized trials are needed to resolve continuing uncertainties about the safety and possible benefits of shorter hospital stays. (BIRTH 24:3, September 1997)