bluuebunny/crossref_metadata_2025_split huggingface dataset:
Linking frugivore activity to early recruitment of a bird dispersed tree, Eugenia umbelliflora (Myrtaceae) in the Atlantic rainforest
Authors: CÔRTES MARINA CORRÊA , CAZETTA ELIANA , STAGGEMEIER VANESSA GRAZIELE , GALETTI MAURO 
Published: March 2009

AbstractSeed dispersal by animals is a complex process involving several distinct stages: fruit removal by frugivores, seed delivery in different microhabitats, seed germination, seedling establishment, and adult recruitment. Nevertheless, studies conducted until now have provided scarce information concerning the sequence of stages in a plant's life cycle in its entirety. The main objective of this study was to evaluate the immediate consequences of frugivore activity for Eugenia umbelliflora (Myrtaceae) early recruitment by measuring the relative importance of each fruit‐eating bird species on the establishment of new seedlings in scrub and low restinga vegetation in the Atlantic rainforest, Brazil. We conducted focal tree observations on E. umbelliflora trees recording birds' feeding behaviour and post‐feeding movements. We also recorded the fate of dispersed seeds in scrub and low restinga vegetation. We recorded 17 bird species interacting with fruits in 55 h of observation. Only 30% of the handled fruits were successfully removed. From 108 post flight movements of exit from the fruiting trees, 30.6% were to scrub and 69.4% to low restinga forest. Proportion of seed germination was higher in low restinga than in the scrub vegetation. Incorporating the probabilities of seeds' removal, deposition, and germination in both sites, we found that the relative importance of each frugivorous bird as seed dispersers varies largely among species. Turdus amaurochalinus and Turdus rufiventris were the best dispersers, together representing almost 12% probability of seed germination following removal. Our results show the importance of assessing the overall consequence of seed dispersal within the framework of disperser effectiveness, providing a more comprehensive and realistic evaluation of the relative importance of different seed dispersers on plant population dynamics.
Environmental controls and patterns of cumulative radial increment of evergreen tree species in montane, temperate rainforests of Chiloé Island, southern Chile
Authors: PÉREZ CECILIA A. , CARMONA MARTÍN R. , ARAVENA JUAN CARLOS , FARIÑA JOSÉ M. , ARMESTO JUAN J. 
Published: March 2009

AbstractWe investigated the local environmental controls on daily fluctuations of cumulative radial increment and cambial hydration of three dominant, evergreen tree species from montane, Coastal rainforests of Chiloé Island, Chile (42° 22′ S). During 2 years (1997–1998 and 1998–1999) we recorded hourly cumulative radial increments using electronic band dendrometers in the long‐lived conifer Fitzroya cupressoides (Cupressaceae), the evergreen broad‐leaved Nothofagus nitida (Nothofagaceae), and the narrow‐leaved conifer Podocarpus nubigena (Podocarpaceae). We also measured soil and cambial tissue hydration using capacitance sensors, together with air and soil temperature and rainfall during the period of the study. In addition, we collected cores of these tree species to evaluate how dendrometer measurements reflect annual tree ring width. One‐year long daily time series of cumulative radial increments suggests that radial growth of Fitzroya cupressoides was initiated slowly in early spring, with a maximum in early summer. Multiple regressions showed positive relations between daily precipitation and radial index (i.e. the difference in cumulative radial increment of two consecutive days) in the three species. According to path analysis there was a significant direct effect of changes in tree hydration on radial index of the three focal species. In emergent, pioneer species such as Nothofagus and Fitzroya, radial index was negatively affected by changes in maximum air temperature and photosynthetically active radiation, probably because of high evapotranspiration demand on warm sunny days. The shade‐tolerant species Podocarpus nubigena was positively affected by photosynthetically active radiation. Our diel scale findings support the use of tree ring widths for reconstructing past climate in these southern temperate forests and provide evidence that rainforest trees may be highly sensitive to future declines in rainfall and temperature increases during summer.
Habitat preferences of the noisy miner (Manorina melanocephala) – a propensity for prime real estate?
Authors: OLDLAND JOANNE M. , TAYLOR RICK S. , CLARKE MICHAEL F. 
Published: March 2009

AbstractThis study investigated habitat characteristics that have been postulated to influence the occurrence of noisy miners (Manorina melanocephala Family Meliphagidae). It builds on an earlier study that identified corners along remnant edges as important predictors of the presence of noisy miners in large blocks of remnant vegetation (>300 ha). Six habitat characteristics were recorded at 39 corner sites within the box‐ironbark region of Victoria. We failed to detect any significant effect of the density of understorey vegetation on the likelihood of noisy miners occupying a site, but this might have been an artefact of prolonged drought conditions. The most powerful predictors of the presence of noisy miners at remnant corners were found to be soil type and the proportion of canopy trees at a site that were yellow gum (Eucalyptus leucoxylon), with noisy miners being associated with deeper, more fertile soils and higher proportions of yellow gums present. As yellow gum is a prolific and reliable nectar producer, the inherent productivity of a site might be more important in determining the attractiveness of a site to noisy miners than structural attributes like the presence or absence of an understorey. Noisy miners are sedentary colonial birds that occupy year‐round territories, often at high densities. Sites capable of supporting such high density occupation year‐round might be limited to the most productive sites within the landscape. This productivity hypothesis has potentially profound implications for other woodland avifauna, as noisy miners might be excluding other woodland birds from some of the most fertile components of the landscape; components that are already rare in the box‐ironbark region due preferential clearing for agriculture at the time of settlement.
Deeply divergent mitochondrial lineages reveal patterns of local endemism in chironomids of the Australian Wet Tropics
Authors: KROSCH MATT N. , BAKER ANDREW M. , MCKIE BRENDAN G. , MATHER PETER B. , CRANSTON PETER S. 
Published: March 2009

AbstractThe Wet Tropics bioregion of north‐eastern Australia has been subject to extensive fluctuations in climate throughout the late Pliocene and Pleistocene. Cycles of rainforest contraction and expansion of dry sclerophyll forest associated with such climatic fluctuations are postulated to have played a major role in driving geographical endemism in terrestrial rainforest taxa. Consequences for the distributions of aquatic organisms, however, are poorly understood. The Australian non‐biting midge species Echinocladius martini Cranston (Diptera: Chironomidae), although restricted to cool, well‐forested freshwater streams, has been considered to be able to disperse among populations located in isolated rainforest pockets during periods of sclerophyllous forest expansion, potentially limiting the effect of climatic fluctuations on patterns of endemism. In this study, mitochondrial COI and 16S data were analysed for E. martini collected from eight sites spanning the Wet Tropics bioregion to assess the scale and extent of phylogeographic structure. Analyses of genetic structure showed several highly divergent cryptic lineages with restricted geographical distributions. Within one of the identified lineages, strong genetic structure implied that dispersal among proximate (<1 km apart) streams was extremely restricted. The results suggest that vicariant processes, most likely due to the systemic drying of the Australian continent during the Plio‐Pleistocene, might have fragmented historical E. martini populations and, hence, promoted divergence in allopatry.
Petals may act as a reward: myrmecochory in shrubby Darwinia species of south‐eastern Australia
Authors: AULD TONY D. 
Published: March 2009

AbstractThe removal rates of fruits (the diaspore) were assessed in exclusion experiments in three shrubby species of Darwinia, endemic to the Sydney Basin of south‐eastern Australia. There was a clear pattern of fruit removal in just a few days by small species of ants from the genera Iridomyrmex, Crematogaster and Pheidole. When only ants had access to fruits an average of 41% of fruits were removed, whereas when only vertebrates had access an average of 13% of fruits were removed. There was some variation in the number of fruits removed both between species and within species across study sites or annual seed crops. When ants had access to seeds this variation in removal amounted to 10–80% over 1–4 days. Uniquely in Darwinia, it is the old petals (which remain attached to the fruit) that are attractive to the ants, rather than a specific lipid body. This likely represents a case of successful ecological fitting by Darwinia to take advantage of the widespread presence of myrmecochory in the Australian flora.
Dynamics of free intracellular Ca2+ during synaptic and spike activity of cricket tibial motoneurons
Authors: Baden Tom , Hedwig Berthold 
Published: March 2009

AbstractFor all nervous systems, motoneurons are the main output pathway. They are involved in generating episodic motor activity as well as enduring motor rhythms. To determine whether changes in cytosolic Ca2+ correlate with motor performance, we studied the spatiotemporal dynamics, mode of entry and role of free intracellular Ca2+ in cricket (Gryllus bimaculatus) front leg tibial extensor and flexor motoneurons. Synaptic activation or intracellular depolarising current injection uniformly increased Ca2+ with the same dynamics throughout the primary and secondary branches of the dendritic tree of all motoneurons. Ca2+ rise times (mean τrise, 233–295 ms) were lower than decay times (mean τdecay, 1927–1965 ms), and resulted in a Ca2+ plateau during repetitive activation, such as during walking. The neurons therefore operate with a different Ca2+ level during walking than during episodic leg movements. Ca2+ enters the dendritic processes of motoneurons via a voltage‐activated mechanism. Entry is driven by subthreshold excitation, and is largely independent of the neurons’ spiking activity. To what extent ligand‐activated mechanisms of Ca2+ entry operate remains uncertain. We found no evidence for any prominent Ca2+‐activated secondary currents in these motoneurons. Excitatory postsynaptic potentials evoked by extracellular stimulation of descending neurons were unaffected by the level of free intracellular Ca2+. The activity of tibial motoneurons therefore appears to be only weakly dependent on the level of free intracellular Ca2+ in dendrites. This is different to what has been found for many other neurons studied, and may represent an essential prerequisite for insect motoneurons to support a wide range of both episodic and rhythmic motor sequences underlying behaviour.
Dynamic Capabilities, Government Policies, and Performance in Firms from Emerging Economies: Evidence from India and Pakistan
Authors: Malik Omar R. , Kotabe Masaaki 
Published: March 2009

abstractIn this study we developed a model of the dynamic capability development mechanisms in Emerging Market manufacturing Firms (EMF). We identified three dynamic capability development mechanisms: organizational learning, reverse engineering, and manufacturing flexibility. We generated hypotheses based on this framework, linking these mechanisms with firm performance. We also modelled the roles played by managerial use of two types of government policies: input supporting policies and marketing supporting policies. We tested our hypotheses on a sample of Indian and Pakistani manufacturing firms. Results showed that organizational learning, reverse engineering and manufacturing flexibility had significant impacts on EMF performance. Additionally, organizational learning combined with input supporting government policies enhanced performance, and the combination of manufacturing flexibility and marketing supporting government policies had an insignificant influence on performance.
Governance, Negotiations, and Alliance Dynamics: Explaining the Evolution of Relational Practice
Authors: Ness Håvard 
Published: March 2009

abstractThis paper explores relational practice in strategic alliances. Focusing on how governance mechanisms and negotiation strategies evolve and form patterns of interaction that are under influence of both recursive and adaptive forces, four modes of relational practice are discussed: recursively integrative, recursively distributive, adaptive toward integrative, and adaptive toward distributive. Three longitudinal cases are examined. I find that different contractual conditions enable (or restrain) interaction patterns. Negotiation behaviour, in turn, affects future contractual conditions and their combination and recombination form the evolution of relational practice. As relationships progress, initial governance mechanisms are complemented and negotiation behaviours change. I explain how perceptions of both process and relational outcomes influence relational practice. In addition, I explicate why relational practices have both recursive and adaptive characteristics, and identify conditions that cause relational practices to move towards more integrative or distributive modes.
Bridging the Rigour–Relevance Gap in Management Research: It's Already Happening!
Authors: Hodgkinson Gerard P. , Rousseau Denise M. 
Published: March 2009

abstractKieser and Leiner (2009) maintain that the rigour–relevance gap in management research is fundamentally unbridgeable because researchers and the researched inhabit separate social systems. They argue that it is impossible to assess the relevance of research outputs within the system of science and that neither action research nor related approaches to collaborative research can succeed in producing research that is rigorous as well as relevant. In reply, we show how their analysis is inconsistent with available evidence. Drawing on a diversity of management research domains, we provide counter‐illustrations of work where researchers, in a number of cases in collaboration with practitioners, have generated knowledge that is both socially useful and academically rigorous.
Trade, Tariffs and Total Factor Productivity: The Case of Spanish Firms
Authors: Dovis Marion , Milgram‐Baleix Juliette 
Published: March 2009

AbstractThe aim of this paper is to examine the sensitivity of total factor productivity (TFP) to foreign competition in the case of a European country. Using the Olley and Pakes method, we calculate the TFP of Spanish manufacturing firms and study the impact of EU tariffs and the presence of foreign products and imports on TFP at the firm level. Applying the System‐GMM method, we find that TFP is negatively impacted by European tariffs, whereas competition in the form of the increased presence of foreign products in the domestic market and firm imports leads to improvements in the TFP. Moreover, these two effects are complementary. We also find evidence of important asymmetries among firms depending on their involvement in foreign markets.
EMG of chimpanzee shoulder muscles during knuckle‐walking: problems of terrestrial locomotion in a suspensory adapted primate
Authors: Larson Susan G. , Stern Jack T. 
Published: March 2009

By most accounts, the upper limb of the chimpanzee is primarily adapted to suspensory postures and locomotion. In order to determine how the derived morphology of the chimpanzee forelimb has affected the form of quadrupedal locomotion displayed by these animals, electromyographic activity patterns of 10 shoulder muscles during knuckle‐walking in two chimpanzee subjects were analysed and compared to data on the opossum and cat taken from the literature. Telemetered electromyography coupled with simultaneous video recording was employed in order to study unfettered locomotion in the chimpanzee subjects.Chimpanzees are characterized by a quadrupedal gait in which the hind limb overstrides the ipsilateral forelimb. Forelimb position in the plane of abduction/adduction is significantly affected by whether the hind limb passes inside or outside its ipsilateral forelimb. The degree of abduction adduction of the forelimb, in turn, influences many of the muscle activity patterns. That is, some muscles would be more frequently or less frequently active, depending on whether the arm was relatively abducted or adducted during a stride. Thus, there can be no single motor programme that generates the step cycle in chimpanzees.While there are some parallels between muscle recruitment patterns for chimpanzee, opossum and cat quadrupedalism, the results of this study also indicate that many aspects of muscle use in chimpanzees have been significantly influenced by factors related to increased mobility of the upper limb. Finally, this study has revealed that moving the arm forward during swing phase of knuckle‐walking is not a simple product of muscular elTort. and that other mechanisms must be involved. However, it is unclear at present exactly what these mechanisms may be.
Testing historical phylogeographic inferences with contemporary gene flow data: population genetic structure of the Qinghai toad‐headed lizard
Authors: Wang Y. , Zhan A. , Fu J. 
Published: March 2009

AbstractUsing data from 11 microsatellite DNA loci and a population genetic approach, the phylogeographic patterns of the Qinghai toad‐headed lizard Phrynocephalus vlangalii revealed by mitochondrial DNA (mtDNA) were tested and the congruence between the nuclear and mitochondrial genes was examined. Both analysis of molecular variance (AMOVA) and BARRIER analyses suggested that the Arjin and the A'nyemaqen Mountains were significant genetic barriers to contemporary gene flow of the P. vlangalii populations. On the other hand, the Qaidam populations, where no major mountains are present, showed a weak but significant isolation by distance pattern. The patterns of population genetic structure were largely congruent with the phylogeographic patterns inferred from the mtDNA, and therefore, supported the hypothesis that the uplift of the Arjin and the A'nyemaqen Mountains caused the initial vicariant events that led to the formation of the diverged lineages within P. vlangalii. The only major difference between the mtDNA and nuclear DNA (nuDNA) results was the allocation of variance to different hierarchical levels in AMOVA. While the among group component, which were defined by mountains, accounted for most of the mitochondrial variance (81.73%), most of the nuDNA variance was at the among individuals within population level (83.69%). Differences in effective population sizes, social structure and male/female dispersal patterns might have contributed to the discrepancy.
BAG‐1M is up‐regulated in hippocampus of Alzheimer’s disease patients and associates with tau and APP proteins
Authors: Elliott Evan , Laufer Offir , Ginzburg Irith 
Published: March 2009

AbstractThe accumulation of tau and amyloid beta proteins is the major molecular pathology of Alzheimer’s disease (AD). The mechanisms leading to the accumulation of these proteins are not completely clear. Hsc‐70/Hsp‐70, a chaperone protein, has been shown to bind both these proteins and regulate their degradation. We have previously shown that the co‐chaperone protein BAG‐1 can inhibit the degradation of tau by forming a complex with Hsc‐70 and tau. In this current work, we show that there is an increase in the BAG‐1M isoform in the hippocampus of AD patients. In addition, BAG‐1 binds to both tau and amyloid precursor protein physically, and is found highly expressed in the same neurons that contain intracellular tau or amyloid in hippocampal sections from AD patients. Over‐expression of BAG‐1M in cell culture also induced an increase in both tau and amyloid precursor protein levels. In conclusion, we report a specific increase of BAG‐1M in human AD patients, which is both physically and functionally associated to the two major molecular markers of AD.
Interleukin‐1β enhances nucleotide‐induced and α‐secretase‐dependent amyloid precursor protein processing in rat primary cortical neurons via up‐regulation of the P2Y2 receptor
Authors: Kong Qiongman , Peterson Troy S. , Baker Olga , Stanley Emily , Camden Jean , Seye Cheikh I. , Erb Laurie , Simonyi Agnes , Wood W. Gibson , Sun Grace Y. , Weisman Gary A. 
Published: March 2009

AbstractThe heterologous expression and activation of the human P2Y2 nucleotide receptor (P2Y2R) in human 1321N1 astrocytoma cells stimulates α‐secretase‐dependent cleavage of the amyloid precursor protein (APP), causing extracellular release of the non‐amyloidogenic protein secreted amyloid precursor protein (sAPPα). To determine whether a similar response occurs in a neuronal cell, we analyzed whether P2Y2R‐mediated production of sAPPα occurs in rat primary cortical neurons (rPCNs). In rPCNs, P2Y2R mRNA and receptor activity were virtually absent in quiescent cells, whereas overnight treatment with the pro‐inflammatory cytokine interleukin‐1β (IL‐1β) up‐regulated both P2Y2R mRNA expression and receptor activity by four‐fold. The up‐regulation of the P2Y2R was abrogated by pre‐incubation with Bay 11‐7085, an IκB‐α phosphorylation inhibitor, which suggests that P2Y2R mRNA transcript levels are regulated through nuclear factor‐κ‐B (NFκB) signaling. Furthermore, the P2Y2R agonist Uridine‐5′‐triphosphate (UTP) enhanced the release of sAPPα in rPCNs treated with IL‐1β or transfected with P2Y2R cDNA. UTP‐induced release of sAPPα from rPCNs was completely inhibited by pre‐treatment of the cells with the metalloproteinase inhibitor TACE inhibitor (TAPI‐2) or the phosphatidylinositol 3‐kinase (PI3K) inhibitor LY294002, and was partially inhibited by the MAPK/extracellular signal‐regulated kinase inhibitor U0126 and the protein kinase C inhibitor GF109203. These data suggest that P2Y2R‐mediated release of sAPPα from cortical neurons is directly dependent on a disintegrin and metalloproteinase (ADAM) 10/17 and PI3K activity, whereas extracellular signal‐regulated kinase 1/2 and PI3K activity may indirectly regulate APP processing. These results demonstrate that elevated levels of pro‐inflammatory cytokines associated with neurodegenerative diseases, such as IL‐1β, can enhance non‐amyloidogenic APP processing through up‐regulation of the P2Y2R in neurons.