bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluating performance costs of sexually selected traits
Authors: OUFIERO C. E. , GARLAND T. 
Published: April 2007

Summary

Aspects of locomotor performance are thought to be important in a variety of natural contexts, including foraging and escaping from predators. The role of locomotor abilities in sexual selection is less well documented, but is probably of wide importance.
Sexual selection may exaggerate traits beyond their optimum with respect to biomechanical or physiological function, thus imposing ‘costs’ of various types. Locomotor performance, in conjunction with its lower‐level determinants and its behavioural and ecological consequences, constitutes an ideal set of phenotypes with which to study such costs.
Organisms may possess traits that compensate for the negative effects of sexually selected traits on performance abilities. Ignoring these may lead to erroneous conclusions about the cost of a putatively sexually selected trait. At the same time, ignoring the effects of sexual selection on functionally important traits may lead us to underestimate their functional significance.
Many properties of organisms are affected by, or at least correlate with, overall body size, so this must be considered in any study of adaptation or sexual selection. For interspecific or interpopulation comparative studies, phylogeny must also be considered in statistical analyses.
We present a hypothetical data set that illustrates the perils of ignoring potential compensatory mechanisms when studying the costs of a sexually selected trait. We also discuss different ways of studying costs, including analyses of a single sex and of the differences between the sexes.
Predicting grazing damage by white‐fronted geese under different regimes of agricultural management and the physiological consequences for the geese
Authors: AMANO TATSUYA , USHIYAMA KATSUMI , FUJITA GO , HIGUCHI HIROYOSHI 
Published: April 2007

Summary

One of the most common human–wildlife conflicts is damage by wildlife to agricultural crops. In order to propose cost‐effective measures to address wildlife damage and also to manage pest animals that are of conservation interest, both the effects of wildlife on agricultural crop yield and the effects of mitigation measures on wildlife must be evaluated.
In this study, we applied a behaviour‐based model to the conflict between agricultural production and white‐fronted geese Anser albifrons causing damage to wheat crops around Lake Miyajimanuma in northern Japan. The model is spatially explicit, individual‐ and physiology based, and therefore tracks the day‐to‐day spatial distribution of geese and the physiological dynamics of fat deposition by each goose throughout the staging period.
In our simulations, the establishment of alternative feeding areas (AFAs) for the geese was predicted to be cost‐effective for alleviating wheat damage if the number of AFAs and the amount of alternative food supplied was balanced carefully. However, even with the most cost‐effective combination, a reduction of up to 23% in heavily damaged areas was the best outcome that could be achieved.
Alternatively, locating wheat fields further away from the roost site and also encouraging farmers to leave rice grain remains, the main food resource for the geese, could greatly reduce wheat damage without a detrimental impact on the geese (measured in terms of fat deposition) over a wide range of simulated population sizes.
Synthesis and applications. The suggested combination of mitigation measures (relocation of wheat fields and inhibition of rice‐reducing agricultural practices) should qualify to be tested in practice for alleviating agriculture–geese conflicts in the study area. This study demonstrates that behaviour‐based models can be applied successfully to agriculture–wildlife conflicts, allowing us to evaluate the effects of mitigation measures by quantitative predictions. Behaviour‐based models can be applied to most cases of agriculture–wildlife conflicts involving adaptive foraging behaviour of animals.
Potential ecological and epidemiological factors affecting the persistence of classical swine fever in wild boarSus scrofapopulations
Authors: KRAMER‐SCHADT S. , FERNÁNDEZ N. , THULKE H.‐H. 
Published: April 2007

ABSTRACTClassical swine fever has increased in economic importance since it has become endemic in some wild boarSus scrofapopulations in Europe. The mechanism of disease persistence is still not well understood, and several aspects of both the ecology of boar and the virus are claimed to be responsible for disease persistence.We review literature on the spread and persistence of the disease in free‐ranging wild boar. We determine whether the available knowledge can explain the observed patterns via mechanistic processes and their interactions, and assemble knowledge in a conceptual model.We speculate that the most important factor explaining disease persistence is an alteration in disease outcome, resulting in individual courses with prolonged infectiousness or a sustained reproductive population through immunity. This effect is reinforced by high wild boar numbers either within sites or scattered over larger areas.We highlight the sparse knowledge of disease transmission between wild boar. We derive management suggestions for different phases of an outbreak based on the conceptual model and advocate the use of model‐based investigations to test alternative management options.
Early responses associated with chronic pathology in murine schistosomiasis
Authors: CÊTRE‐SOSSAH C. B. , MONTESANO M. A. , FREEMAN G. L. , WILLARD M. T. , COLLEY D. G. , SECOR W. E. 
Published: April 2007

SUMMARY Inbred male CBA/J mice infected with Schistosoma mansoni develop either hypersplenomegaly syndrome (HSS) or moderate splenomegaly syndrome (MSS) by 20 weeks of infection. Pathologically and immunologically, MSS and HSS closely parallel the intestinal and hepatosplenic clinical forms of schistosomiasis in humans, respectively. By 6 weeks after infection, mice that eventually will become MSS develop T cell‐stimulatory, cross‐reactive idiotypes (CRI) while HSS mice never produce CRI. Because presence of CRI is useful to predict degree of chronic pathology, we used this measure to investigate what other early immunological events occurred in animals destined to develop severe morbidity. At 8 weeks of infection, there was a strong inverse correlation between CRI and splenomegaly, egg counts, and liver hydroxyproline. Similarly, phorbol myristate acetate (PMA)‐ and ionomycin‐stimulated intracellular cytokine expression of IL‐4, IL‐5, and GM‐CSF in splenic CD4+ T cells was inversely correlated with serum CRI and directly correlated with spleen size. In contrast, spleen cell intracellular TNF‐α and peritoneal cell production of nitric oxide demonstrated positive correlations with CRI and inverse correlations with measures of morbidity. Surprisingly, IL‐10 and IFN‐γ were not correlated with CRI levels. These studies link chronic pathology to certain immunological responses during the acute phase of schistosomiasis.
Effect of extending the platelet storage time on platelet utilization: predictions from a mathematical model of prophylactic platelet support
Authors: Pereira A. , Sanz C. 
Published: April 2007

summary Bacterial culturing (BCU) or photochemical treatment (PCT) of platelet (PLT) concentrates may permit extending the storage time to 7 days at the cost of decreased viability of transfused PLTs. This study was aimed at predicting the impact this may have on the routine management of patients on prophylactic PLT support.The method included a mathematical model that represents the dynamics of prophylactic PLT support with standard, BCU or PCT PLTs. Data on posttransfusion PLT kinetics and the effect of PCT or storage time on PLT recovery and survival were obtained from published studies.Variables that influenced the level of PLT usage were the proportion of transfusions supplied with PLT on the last day of shelf‐life, the use of PCT and the assumed degree of synergy between clinical factors of PLT consumption and either PCT or storage time. In the reference‐case scenario, extending the PLT shelf‐life to 7 days by BCU or PCT increased by 9 and 19%, respectively, the number of PLT transfusions per patient‐year. In the worst‐case scenario, these figures rose to 27 and 38%, respectively. Despite more intensive PLT usage, in most scenarios, the time that patients spent at PLT counts <10 × 109 L−1 increased.Extending the shelf‐life of PLT products will increase PLT usage. Such increase may be disproportionately larger for patients with complex conditions if there is a synergic interaction between storage time or PCT and clinical factors of PLT consumption, an issue that is worth further clinical research.
Ludwik Zamenhof: a colleague of rare distinction
Authors: Littlewood Kenneth R 
Published: April 2007

AbstractLudwik Zamenhof trained as an ophthalmologist in Vienna at the end of the 19th century. He is best known as the originator of Esperanto and devoted his life to the ideals of secular humanism and ethnic tolerance. Few individuals left a nobler legacy, yet in a tragic irony when the Nazis invaded Poland in World War Two his family were singled out for persecution.
CD40 promotion of amyloid beta production occurs via the NF‐κB pathway
Authors: Ait‐Ghezala Ghania , Volmar Claude‐Henry , Frieling Jeremy , Paris Daniel , Tweed Miles , Bakshi Pancham , Mullan Michael 
Published: April 2007

AbstractThe CD40 receptor is a member of the tumor necrosis factor (TNF) super‐family of trans‐membrane receptors. Interaction of CD40 with its ligand CD40L mediates a broad range of immune and inflammatory responses in the periphery and in the central nervous system. Recently it has been suggested that CD40/CD40L interaction is involved in amyloid precursor protein (APP) processing and Alzheimer's disease (AD)‐like pathology in transgenic mouse models of AD. We have previously shown that pharmacologically inhibiting CD40/CD40L interaction improves memory deficits in the PSAPP AD mouse model. We have also recently shown that CD40 deficiency mitigates amyloid deposition in APPsw and PSAPP mouse models. In the present report, using human embryonic kidney cells (HEK293) over‐expressing both the APPsw mutation and CD40, we demonstrate that CD40/CD40L interaction directly increases the production of APP metabolites (Aβ 1–40, Aβ 1–42, CTFs, sAPPβ and sAPPα). The results also show that CD40/CD40L interaction affects APP processing via the NF‐κB pathway. Using NFκB inhibitors and SiRNAs to silence diverse elements of the NFκB pathway, we observe a reduction in levels of both Aβ 1–40 and Aβ 1–42. Taken together, our results further suggest that CD40L stimulation may be a key component in AD pathology and that elements of the NF‐κB pathway may be suitable targets for therapeutic approaches against AD.
Forebrain mineralocorticoid receptor overexpression enhances memory, reduces anxiety and attenuates neuronal loss in cerebral ischaemia
Authors: Lai Maggie , Horsburgh Karen , Bae Sung‐Eun , Carter Roderick N. , Stenvers Dirk J. , Fowler Jill H. , Yau Joyce L. , Gomez‐Sanchez Celso E. , Holmes Megan C. , Kenyon Christopher J. , Seckl Jonathan R. , Macleod Malcolm R. 
Published: April 2007

AbstractThe nuclear mineralocorticoid receptor (MR), a high‐affinity receptor for glucocorticoids, is highly expressed in the hippocampus where it underpins cognitive, behavioural and neuroendocrine regulation. Increased neuronal MR expression occurs early in the response to cellular injury in vivo and in vitro and is associated with enhanced neuronal survival. To determine whether increased neuronal MR might be causal in protecting against ischaemic damage in vivo we generated a forebrain‐specific MR‐overexpressing transgenic mouse (MR‐Tg) under the control of the CamKII alpha promoter, and subjected mice to transient cerebral global ischaemia induced by bilateral common carotid artery occlusion for 20 min. We also separately assessed the effects of MR overexpression on hypothalamic–pituitary–adrenal (HPA) axis activity and cognitive and affective functions in noninjured animals. Our results showed that MR‐Tg mice had significantly reduced neuronal death following transient cerebral global ischaemia compared to wild‐type littermates. This effect was not associated with alterations in basal or poststress HPA axis function or in arterial blood pressure. MR‐Tg mice also demonstrated improved spatial memory retention, reduced anxiety and altered behavioural response to novelty. The induction of neuronal MR appears to offer a protective response which has potential therapeutic implications in cerebral ischaemia and cognitive and affective disorders.
The relationship between brain activity and peak grip force is modulated by corticospinal system integrity after subcortical stroke
Authors: Ward Nick S. , Newton Jennifer M. , Swayne Orlando B. C. , Lee Lucy , Frackowiak Richard S. J. , Thompson Alan J. , Greenwood Richard J. , Rothwell John C. 
Published: April 2007

AbstractIn healthy human subjects, the relative contribution of cortical regions to motor performance varies with the task parameters. Additionally, after stroke, recruitment of cortical areas during a simple motor task varies with corticospinal system integrity. We investigated whether the pattern of motor system recruitment in a task involving increasingly forceful hand grips is influenced by the degree of corticospinal system damage. Nine chronic subcortical stroke patients and nine age‐matched controls underwent functional magnetic brain imaging whilst performing repetitive isometric hand grips. Target grip forces were varied between 15% and 45% of individual maximum grip force. Corticospinal system functional integrity was assessed with transcranial magnetic stimulation. Averaged across all forces, there was more task‐related activation compared with rest in the secondary motor areas of patients with greater corticospinal system damage, confirming previous reports. However, here we were primarily interested in regional brain activation, which covaried with the amount of force generated, implying a prominent executive role in force production. We found that in control subjects and patients with lesser corticospinal system damage, signal change increased linearly with increasing force output in contralateral primary motor cortex, supplementary motor area and ipsilateral cerebellum. In contrast, in patients with greater corticospinal system damage, force‐related signal changes were seen mainly in contralesional dorsolateral premotor cortex, bilateral ventrolateral premotor cortices and contralesional cerebellum, but not ipsilesional primary motor cortex. These findings suggest that the premotor cortices might play a new and functionally relevant role in controlling force production in patients with more severe corticospinal system disruption.
Age‐related differences in the local cellular and molecular responses to injury in developing spinal cord of the opossum, Monodelphis domestica
Authors: Lane M. A. , Truettner J. S. , Brunschwig J‐P. , Gomez A. , Bunge M. B. , Dietrich W. D. , Dziegielewska K. M. , Ek C. J. , VandeBerg J. L. , Saunders N. R. 
Published: April 2007

AbstractImmature spinal cord, unlike adult, has an ability to repair itself following injury. Evidence for regeneration, structural repair and development of substantially normal locomotor behaviour comes from studies of marsupials due to their immaturity at birth. We have compared morphological, cellular and molecular changes in spinal cords transected at postnatal day (P)7 or P14, from 3 h to 2 weeks post‐injury, in South American opossums (Monodelphis domestica). A bridge between severed ends of cords was apparent 5 days post‐injury in P7 cords, compared to 2 weeks in P14. The volume of neurofilament (axonal) material in the bridge 2 weeks after injury was 30% of control in P7‐ but < 10% in P14‐injured cords. Granulocytes accumulated at the site of injury earlier (3 h) in P7 than in P14 (24 h)‐injured animals. Monocytes accumulated 24 h post‐injury and accumulation was greater in P14 cords. Accumulation of GFAP‐positive astrocytes at the lesion occurred earlier in P14‐injured cords. Neurites and growth cones were identified ultrastructurally in contact with astrocytes forming the bridge. Results using mouse inflammatory gene arrays showed differences in levels of expression of many TGF, TNF, cytokine, chemokine and interleukin gene families. Most of the genes identified were up‐regulated to a greater extent following injury at P7. Some changes were validated and quantified by RT‐PCR. Overall, the results suggest that at least some of the greater ability to recover from spinal cord transection at P7 compared to P14 in opossums is due to differences in inflammatory cellular and molecular responses.
Detection psychophysics of intracortical microstimulation in rat primary somatosensory cortex
Authors: Butovas Sergejus , Schwarz Cornelius 
Published: April 2007

AbstractA problem of purposeful intracortical microstimulation is the long duration of neuronal integration time and the associated complex temporal interactions of effects to individual pulses in trains. Here we investigated the effects of repetitive stimuli on perception. We trained head‐restraint rats to indicate the detection of cortical microstimulation in infragranular layers of barrel cortex. Three stimulus parameters: stimulus intensity, number of pulses and frequency were varied, and psychometric detection curves were assessed using the method of constant stimuli. The average psychophysical threshold of single pulses was 2.0 nC − a measure very close to what has been found earlier for the evocation of short‐latency action potentials in neurons near the stimulation electrode. Detection of single‐pulse stimulation always saturated at probabilities of about 0.8. In contrast, repetitive stimuli gave rise to lower thresholds (by a factor of two at 15 pulses, 320 Hz), and to saturation at probabilities close to 1. Interestingly, a large fraction of these perceptual benefits was observed already with double pulses. Moreover, the perceptual efficacy of individual pulses was higher using double pulses compared with longer sequences, i.e. double pulses were detected better than expected from the assumption of independence of single‐pulse effects, while trains of 15 pulses fell well short of this expectation. The present results thus point to double‐pulse stimulation as an optimal choice when trading economic stimulation against optimizing of the percept.
Androgen receptor is essential for sexual differentiation of responses to olfactory cues in mice
Authors: Bodo Cristian , Rissman Emilie F. 
Published: April 2007

AbstractDuring sexual differentiation males and females are exposed to different levels of testosterone, which promotes sex differences in the adult brain and in behavior. Testosterone can act after aromatization or reduction via a number of steroid hormone receptors. Here we provide new evidence that the androgen receptor (AR) is essential for sexual differentiation in mice. We used mice carrying the testicular feminization (Tfm) mutation of the AR. Adult Tfm males, wild‐type male and female littermates were gonadectomized and given subcutaneous estradiol implants. In all sexually dimorphic traits, Tfm males had responses equivalent to females and different from males. In simultaneous choice tests, males spent significantly more time investigating female‐soiled bedding, whereas females and Tfm males preferred to investigate male‐soiled bedding. Tfm males and females did not have a partner preference in tests with awake stimulus animals, whereas males showed a preference for females over males. Exposure to male‐soiled, but not clean, bedding produced a significant increase in c‐Fos‐immunoreactive cells in the medial preoptic area and bed nucleus of the stria terminalis in Tfm males and females, no increase was noted in males. Masculine sexual behavior (mounting and thrusting) was not sexually dimorphic, and all groups displayed these behaviors. Our results support data collected in humans suggesting a role for the androgen receptor in sexual differentiation of social preferences and neural responses to pheromones.
An evaluation framework of expertise presence in computer conferences
Authors: Lui Andrew K. , Tsang Philip , Kwan Reggie , Ng Sin Chun , Cheung Yannie H. Y. , Choy Sheung On 
Published: April 2007

AbstractCurrently, for educators and researchers, diagnosing the online interactions specifically related to knowledge and expertise exchanges is challenging. To address the problem, this paper describes a framework for the understanding and measurement of expertise presence in computer conferences. Expertise presence is defined as a persistent contribution of knowledge relevant to the purposes of the computer conferences. The paper includes a technique for measuring the strength of expertise presence from transcripts of computer conferences, and it also envisages a number of applications in online learning diagnosis and research. A case study of the application of the framework to the computer conferences of several online courses is discussed.
All Guts, No Glory: Trading and Diversification among Online Investors
Authors: Anderson Anders 
Published: April 2007

Abstract I explore cross‐sectional portfolio performance in a sample containing 324,736 transactions conducted by 16,831 Swedish investors at an Internet discount brokerage firm during the period May 1999 to March 2002. On average, investors hold undiversified portfolios, show a strong preference for risk, and trade aggressively. I measure performance using a panel data model, and explain the cross‐sectional variation using investors' turnover, portfolio size and degree of diversification. I find that turnover is harmful to performance due to fees, and is therefore more predominant among investors with small portfolios. I argue that the degree of diversification is a proxy for investor skill, and it has a separate and distinct positive effect on performance. Investors underperform the market by about 8.5% per year on average, of which half can be attributed to trading costs.
Au nom de qui? The European Court of Justice between Member States, Civil Society and Union Citizens
Authors: Wernicke Stephan 
Published: April 2007

Abstract:  How does the quest for legitimacy of the European Union relate to the view the European Court of Justice(ECJ) accords to Union citizens, civil society and to private actors? It is submitted that the ECJ is currently developing a jurisprudence under which citizens, as well as their organisations and corporate private actors, are gradually, and in almost complete disregard of the public/private distinction, being included in the matrix of rights and—a crucial point—obligations of the treaties. The ECJ incorporates civil society actors and citizens, beyond notions of representative (citizenship) and participatory (civil society) democracy, into the body of law and thereby reworks its own and the Union's identity. Two core aspects are explored: the first is the reconfiguration of Union citizenship as a norm which triggers the application of the substantive norms of the EC Treaty. The second aspect of this evolution is the creation of ‘private governance’ schemes, i.e. processes in which, as a rule, private action is regarded as action that has to meet the standards of the Treaty. The analysis shows that the court is disentangling itself from the State‐oriented Treaty situation and drawing legitimacy directly from citizens themselves so that judgments should be pronounced ‘In the Name of the Citizens of the European Union’.
‘Union Citizenship is destined to be the fundamental status of nationals of the Member States.’1