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Subregions
Kinds of Subregions Selected AbstractsDisturbance facilitates rapid range expansion of aspen into higher elevations of the Rocky Mountains under a warming climateJOURNAL OF BIOGEOGRAPHY, Issue 1 2010Simon M. Landhäusser Abstract Aim, Trembling aspen (Populus tremuloides Michx.) is absent in the upper foothills region of west-central Alberta because of the cold conditions and short growing season at this high elevation. However, in recent years it appears that aspen has been establishing from seed in this zone and that it has been doing so mainly as a result of forest harvesting. The objectives of this study were to determine the frequency of and types of microsite required for the successful establishment of aspen seedlings at these higher elevations. Location, Rocky Mountains Upper Foothills Natural Subregion of west-central Alberta, Canada. Methods, The current distribution of mature aspen and the presence and absence of aspen seedlings in harvested areas were determined in an area c. 300 km2 in size, using ground and aerial surveys. In an intensive study, 12 belt transects (180 m long and 5 m wide) were established in areas disturbed by forest harvesting at high elevations where no aspen was present prior to harvesting. Transects were surveyed seven growing seasons after disturbance and the microsites occupied by aspen seedlings were characterized according to their substrate and microtopography. Similarly, the availability of different substrates and microtopographic positions were assessed by systematic point sampling on these sites. Results, On level surfaces, aspen seedling regeneration was found up to 200 m higher in elevation than the mature aspen in the original undisturbed forests. Overall, there were 428 seedlings ha,1 established on these transects, and the age distribution indicates that aspen seedlings had established in each of the seven growing seasons since the disturbance. Nearly all of the seedlings (93%) were established on mineral soil microsites and virtually no seedlings were established on undisturbed forest floor layers. Significantly more seedlings were found in concave microtopographic positions. Main conclusions, This study indicates that aspen establishment from seed is currently not a stochastic event and demonstrates that aspen is rapidly expanding its range upslope in the Canadian Rocky Mountain region as a result of forest management practices that expose mineral soil substrates in conjunction with a warming climate. The change in canopy composition from conifer to deciduous forests at these higher elevations will have far-reaching implications for ecosystem processes and functions. [source] The distribution of South American galaxiid fishes: the role of biological traits and post-glacial historyJOURNAL OF BIOGEOGRAPHY, Issue 1 2004Víctor Cussac Abstract Aim, The aim of this work is to update the distribution data of Galaxiidae in South America, relating extant distribution to physiological and reproductive characteristics of the species, latitude, temperature, and post-glacial opportunities for colonization. Location, Lakes and rivers of Patagonia. Methods, We compared, and eventually reconsidered, general data about distribution based on the original literature about capture sites, incorporating several published and unpublished data to the analysis of the biological traits and distribution of Galaxiidae. Results, The more consistent issue in the comprehension of galaxiid biogeography in South America is the ability to establish landlocked populations. Different founding events in landlocked populations of Galaxias maculatus suggest the possible existence of older and younger landlocked populations. This difference in the time since the establishment of lacustrine populations could have been expressed in their ability for colonization of post-glacial areas. Galaxias maculatus, Aplochiton and Brachygalaxias are more clearly excluded from the post-glacial area than G. platei. For all the species we could note a more abundant record of lake populations at the area of glacial refuges. It could be noted that the most successful species, Galaxias platei, is a specialized deep bottom dweller. Deep bottom dwelling helps to endure winter constraints and it appears to be an alternative to the colonization of the littoral and limnetic zones of post-glacial lakes, the prefered habitat of the other Patagonian fish species. Main conclusions, At the end of this process of post-glacial colonization, in the beginning of twentieth century, man introduced several salmonid species in Patagonia. In addition, antropogenic actions had its more recent consequences in global warming. Nowadays we were able to observe new localities for Brazilian fishes into the Austral Subregion and expect some changes in the distribution of Galaxiidae. Northern limits for all species and southern limits for landlocked G. maculatus, Brachigalaxias bullocki and Aplochiton zebra, could be displaced southward. Probably, the species less affected by the changes will be G. platei. These predictions could be accurately formulated using the model of B.J. Shuter & J.R. Post (1990) Transactions of the American Fisheries Society119, 314,336, when biological database on these species are completed. [source] Economic Integration of Yunnan with the Greater Mekong Subregion,ASIAN ECONOMIC JOURNAL, Issue 3 2006Sandra Poncet F14; F15 This paper examines the process of economic integration between the Chinese province of Yunnan and its riparian areas of the Mekong region. The gravity model of trade is used to investigate the evolution of Yunnan's international trade integration between 1988 and 1999. Although Greater Mekong Subregion cooperation efforts have had a positive effect on trade, trade has progressively decreased from an above-standard level to a normal level, according to the gravity model of trade. During this process, Yunnan's trade has increased with other countries such as Singapore, Indonesia and Malaysia. This evolution is in line with Yunnan's development and indicates a progressive re-orientation of its trade toward more developed partners. The results suggest that the Mekong cooperation project has to broaden its perspective, taking into consideration Yunnan's expanding trade relations with countries outside the Greater Mekong Subregion. [source] Contrasting effects of selective lesions of nucleus accumbens core or shell on inhibitory control and amphetamine-induced impulsive behaviourEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 2 2008E. R. Murphy Abstract The core and shell subregions of the nucleus accumbens receive differential projections from areas of the medial prefrontal cortex that have dissociable effects on impulsive and perseverative responding. The contributions of these subregions to simple instrumental behaviour, inhibitory control and behavioural flexibility were investigated using a ,forced choice' task, various parameter manipulations and an omission schedule version of the task. Post-training, selective core lesions were achieved with microinjections of quinolinic acid and shell lesions with ibotenic acid. After a series of behavioural task manipulations, rats were re-stabilized on the standard version of the task and challenged with increasing doses of d - amphetamine (vehicle, 0.5 or 1.0 mg/kg i.p. 30 min prior to test). Neither core- nor shell-lesioned rats exhibited persistent deficits in simple instrumental behaviour or challenges to behavioural flexibility or inhibitory control. Significant differences between lesion groups were unmasked by d- amphetamine challenge in the standard version of the forced task. Core lesions potentiated and shell lesions attenuated the dose-dependent effect of d- amphetamine on increasing anticipatory responses seen in sham rats. These data imply that the accumbens core and shell subregions do not play major roles in highly-trained task performance or in challenges to behavioural control, but may have opposed effects following d- amphetamine treatment. Specifically, they suggest the shell subregion to be necessary for dopaminergic activation driving amphetamine-induced impulsive behaviour and the core subregion for the normal control of this behaviour via conditioned influences. [source] Stimulation of D1-like or D2 dopamine receptors in the shell, but not the core, of the nucleus accumbens reinstates cocaine-seeking behaviour in the ratEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 1 2006Heath D. Schmidt Abstract Although increases in dopamine transmission in the brain are clearly involved in the reinstatement of cocaine seeking, the role of nucleus accumbens dopamine in cocaine priming-induced reinstatement remains controversial. The goal of these experiments was to evaluate the relative contributions of D1-like and D2-like dopamine receptors in the nucleus accumbens core and shell in the reinstatement of cocaine-seeking behaviour. Initially, rats were trained to press a lever for cocaine (0.25 mg, i.v.) using a fixed-ratio 5 (FR5) schedule of reinforcement. Responding was then extinguished by substituting saline for cocaine. During the reinstatement phase, subtype-specific dopamine receptor agonists were microinjected into the nucleus accumbens core or medial shell in order to assess their ability to induce cocaine seeking. Administration of the D1/D5 dopamine receptor agonist SKF-81297 (1.0 µg) into the nucleus accumbens shell, but not core, reinstated drug-seeking behaviour. Similarly, microinjection of quinpirole (3.0 µg), a D2/D3 dopamine receptor agonist, into the nucleus accumbens shell and not core reinstated drug-seeking behaviour. In contrast, administration of the D3- or D4-preferring dopamine receptor agonists PD 128,907 (1.5 and 3.0 µg) and PD 168,077 (0.3 and 3.0 µg), respectively, did not promote reinstatement when administered into either the core or the shell. Taken together, these results indicate that activation of D1/D5 or D2 dopamine receptors, in the limbic shell subregion of the nucleus accumbens but not the basal ganglia-orientated accumbens core, promotes the reinstatement of cocaine-seeking behaviour. [source] Double dissociation of the effects of selective nucleus accumbens core and shell lesions on impulsive-choice behaviour and salience learning in ratsEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 10 2005Helen H. J. Pothuizen Abstract The nucleus accumbens can be subdivided into at least two anatomically distinct subregions: a dorsolateral ,core' and a ventromedial ,shell', and this distinction may extend to a functional dissociation. Here, we contrasted the effects of selective excitotoxic core and medial shell lesions on impulsive-choice behaviour using a delayed reward choice paradigm and a differential reward for low rates of responding (DRL) test, against a form of salience learning known as latent inhibition (LI). Core lesions led to enhanced impulsive choices as evidenced by a more pronounced shift from choosing a continuously reinforced lever to a partially reinforced lever, when a delay between lever press and reward delivery was imposed selectively on the former. The core lesions also impaired performance on a DRL task that required withholding the response for a fixed period of time in order to earn a reward. Medial shell lesions had no effect on these two tasks, but abolished the LI effect, as revealed by the failure of stimulus pre-exposure to retard subsequent conditioning to that stimulus in an active avoidance procedure in the lesioned animals. As expected, selective core lesions spared LI. The double dissociations demonstrated here support a functional segregation between nucleus accumbens core and shell, and add weight to the hypothesis that the core, but not the shell, subregion of the nucleus accumbens is preferentially involved in the control of choice behaviour under delayed reinforcement conditions and in the inhibitory control of goal-directed behaviour. [source] Involvement of NMDA and AMPA/KA receptors in the nucleus accumbens core in instrumental learning guided by reward-predictive cuesEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 6 2005Christian Giertler Abstract The use of reward-predictive cues to guide behavior critically involves the nucleus accumbens. However, little is known regarding the role of ionotropic glutamate receptors in the core subregion of the nucleus accumbens (AcbC) in instrumental learning guided by reward-predictive cues. Here we examined the effects of an intra-AcbC blockade of NMDA and AMPA/KA receptors on the acquisition of an instrumental response in a reaction time (RT) task in rats. In this task, discriminative cues signaled in advance the upcoming reward magnitude (5 or 1 food pellet) associated with a lever release. During early acquisition (days 1,6) rats received daily bilateral injections of either the NMDA receptor antagonist AP5 (5.0 µg per side, n = 14), the AMPA/KA receptor antagonist CNQX (2.5 µg per side, n = 14) or vehicle (0.5 µL per side, n = 19). No treatment was given during late acquisition (days 7,12). The main result was that rats which received intra-AcbC injections of AP5 or CNQX during early acquisition exhibited a general RT increase of responses to high and low reward. However, treatment with AP5 and CNQX did not interfere with discriminative guidance of RTs by cue-associated reward magnitudes, i.e. during acquisition RTs of responses to expected high reward became significantly faster than RTs of responses to expected low reward. Our findings suggest that NMDA and AMPA/KA receptors in the AcbC play a critical role in invigorating responding during instrumental learning, but seem less important in guiding responding according to reward-predictive cues. [source] Alterations of postsynaptic density proteins in the hippocampus of rat offspring from the morphine-addicted mother: Beneficial effect of dextromethorphanHIPPOCAMPUS, Issue 6 2006San Nan Yang Abstract Infants passively exposed to morphine or heroin through their addicted mothers usually develop characteristic withdrawal syndrome of morphine after birth. In such early life, the central nervous system exhibits significant plasticity and can be altered by various prenatal influences, including prenatal morphine exposure. Here we studied the effects of prenatal morphine exposure on postsynaptic density protein 95 (PSD-95), an important cytoskeletal specialization involved in the anchoring of the NMDAR and neuronal nitric oxide synthase (nNOS), of the hippocampal CA1 subregion from young offspring at postnatal day 14 (P14). We also evaluated the therapeutic efficacy of dextromethorphan, a widely used antitussive drug with noncompetitive antagonistic effects on NMDARs, for such offspring. The results revealed that prenatal morphine exposure caused a maximal decrease in PSD-95 expression at P14 followed by an age-dependent improvement. In addition, prenatal morphine exposure reduced not only the expression of nNOS and the phosphorylation of cAMP responsive element-binding protein at serine 133 (CREBSerine-133), but also the magnitude of long-term depression (LTD) at P14. Subsequently, the morphine-treated offspring exhibited impaired performance in long-term learning and memory at later ages (P28,29). Prenatal coadministration of dextromethorphan with morphine during pregnancy and throughout lactation could significantly attenuate the adverse effects as described above. Collectively, the study demonstrates that maternal exposure to morphine decreases the magnitude of PSD-95, nNOS, the phosphorylation of CREBSerine-133, and LTD expression in hippocampal CA1 subregion of young offspring (e.g., P14). Such alterations within the developing brain may play a role for subsequent neurological impairments (e.g., impaired performance of long-term learning and memory). The results raise a possibility that postsynaptic density proteins could serve an important role, at least in part, for the neurobiological pathogenesis in offspring from the morphine-addicted mother and provide tentative therapeutic strategy. © 2006 Wiley-Liss, Inc. [source] Dynamic regulation of T-cell costimulation through TCR,CD28 microclustersIMMUNOLOGICAL REVIEWS, Issue 1 2009Tadashi Yokosuka Summary:, T-cell activation requires contact between T cells and antigen-presenting cells (APCs) to bring T-cell receptors (TCRs) and major histocompatibility complex peptide (MHCp) together to the same complex. These complexes rearrange to form a concentric circular structure, the immunological synapse (IS). After the discovery of the IS, dynamic imaging technologies have revealed the details of the IS and provided important insights for T-cell activation. We have redefined a minimal unit of T-cell activation, the ,TCR microcluster', which recognizes MHCp, triggers an assembly of assorted molecules downstream of the TCR, and induces effective signaling from TCRs. The relationship between TCR signaling and costimulatory signaling was analyzed in terms of the TCR microcluster. CD28, the most valuable costimulatory receptor, forms TCR,CD28 microclusters in cooperation with TCRs, associates with protein kinase C ,, and effectively induces initial T-cell activation. After mature IS formation, CD28 microclusters accumulate at a particular subregion of the IS, where they continuously assemble with the kinases and not TCRs, and generate sustained T-cell signaling. We propose here a ,TCR,CD28 microcluster' model in which TCR and costimulatory microclusters are spatiotemporally formed at the IS and exhibit fine-tuning of T-cell responses by assembling with specific players downstream of the TCR and CD28. [source] How to keep V(D)J recombination under controlIMMUNOLOGICAL REVIEWS, Issue 1 2004Marjorie A. Oettinger Summary:, Breaking apart chromosomes is not a matter to be taken lightly. The possible negative outcomes are obvious: loss of information, unstable chromosomes, chromosomal translocations, tumorigenesis, or cell death. Utilizing DNA rearrangement to generate the desired diversity in the antigen receptor loci is a risky business, and it must be carefully controlled. In general, the regulation is so precise that the negative consequences are minimal or not apparent. They are visible only when the process of V(D)J recombination goes awry, as for example in some chromosomal translocations associated with lymphoid tumors. Regulation is imposed not only to prevent the generation of random breaks in the DNA, but also to direct rearrangement to the appropriate locus or subregion of a locus in the appropriate cell at the appropriate time. Antigen receptor rearrangement is regulated essentially at four different levels: expression of the RAG1/2 recombinase, intrinsic biochemical properties of the recombinase and the cleavage reaction, the post-cleavage /DNA repair stage of the process, and accessibility of the substrate to the recombinase. Within each of these broad categories, multiple mechanisms are used to achieve the desired aims. The major focus of this review is on accessibility control and the role of chromatin and nuclear architecture in achieving this regulation, although other issues are touched upon. [source] An augmented spatial digital tree algorithm for contact detection in computational mechanicsINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 2 2002Y. T. Feng Abstract Based on the understanding of existing spatial digital tree-based contact detection approaches, and the alternating digital tree (ADT) algorithm in particular, a more efficient algorithm, termed the augmented spatial digital tree (ASDT) algorithm, is proposed in the present work. The ASDT algorithm adopts a different point representation scheme that uses only the lower corner vertex to represent a (hyper-)rectangle, with the upper corner vertex serving as the augmented information. Consequently, the ASDT algorithm can keep the working space the same as the original n -dimensional space and, in general, a much better balanced tree can be expected. This, together with the introduction of an additional bounding subregion for the rectangles associated with each tree node, makes it possible to significantly reduce the number of node visits in the region search, although each node visit may be slightly more expensive. Three examples arising in computational mechanics are presented to provide an assessment of the performance of the ASDT. The numerical results indicate that the ASDT is, at least, over 3.9 times faster than the ADT. Copyright © 2002 John Wiley & Sons, Ltd. [source] Panbiogeographical analysis of the genus Bomarea (Alstroemeriaceae)JOURNAL OF BIOGEOGRAPHY, Issue 7 2008Fernando Alzate Abstract Aim, A panbiogeographical analysis of the genus Bomarea was undertaken in order to determine generalized tracks and biogeographical nodes, and to evaluate the current distribution of the genus based on the available tectonic information and the biogeographical regionalization of Latin America. Location, The Neotropical region from northern Mexico to northern Argentina, and the Nearctic and Andean regions. Method, A total of 2205 records of 101 species were analysed, representing 95% of the species assigned to Bomarea. Localities were represented on maps and their individual tracks were drawn. Based on their comparison, generalized tracks were detected and mapped. Nodes were identified in the areas where different generalized tracks were superimposed. Results, Five generalized tracks were recovered. One is located in the Eastern Central America and Western Panamanian Isthmus provinces (Caribbean subregion, Neotropical region), which was supported by three species of Central American distribution. The four remaining generalized tracks were located in South America, in the North Andean Paramo, Cauca and Puna biogeographical provinces. These tracks were supported by species of Bomarea with an Andean distribution. Biogeographical nodes were established in the Central Andean region of Colombia, central Ecuador and central Peru. Main conclusions, The nodes obtained for Bomarea support a hybrid origin for the Andean region, which presents diverse components from both northern and southern South America. Likewise, the track recovered between Colombia and Ecuador includes Andean and Neotropical areas, providing further support for this hypothesis. The nodes obtained are coherent with vicariant elements evident for Bomarea. Species of three clades proposed for Bomarea are distributed in specific generalized tracks. [source] Historical biogeography and distribution of the freshwater cyclopine copepods (Copepoda, Cyclopoida, Cyclopinae) of the Yucatan Peninsula, MexicoJOURNAL OF BIOGEOGRAPHY, Issue 7 2004Eduardo Suárez-Morales Abstract Aim, To determine and analyse the distribution of the freshwater cyclopine copepod fauna of the Yucatan Peninsula (YP) and its relationship with the geological and climatic history of this Neotropical karstic zone. Location, The Yucatan Peninsula, Mexico. Methods, Plotting of georeferenced sites, analysis of local and regional geological and climatic history, analysis and comparison of regional and local faunistic records. Results, Distinct dispersal and/or vicariant processes seem to be linked to the current distributions of the seven genera known in the YP. In general, the endemic hypogean or benthic crevicular forms (i.e. Diacyclops chakan, D. puuc and Mesocyclops chaci), derived from epigean, tropical, widely distributed forms (some of them South American) may have been among the earliest colonizers of the subterranean habitats in the YP. The distribution of these and other endemic forms seem to be related to the Holocene dry periods that desiccated the largest bodies of water and isolated local populations of different species. These vicariant processes resulted in forms with restricted distributional areas; some of these formed sister species that speciated in geographically close localities but related to a common identifiable ancestor. Overall, the processes of cyclopine colonization of the YP show the influence of the South American fauna, as the closest relatives of some species endemic to the YP are South American forms; the Nearctic influence is low. The cyclopine fauna of the YP is formed by a mixture of Nearctic-derived (species of Acanthocyclops), Neotropical (i.e. M. edax, M. longisetus, A. panamensis, Thermocyclops inversus and T. tenuis), and epigean and hypogean endemic forms. The highly dynamic geomorphology of the YP and the recent climatic changes in the Holocene define the YP as a peculiar subregion that harbours a diverse fauna of cyclopine copepods with a high endemism. Main conclusion, The current distribution of cyclopine copepods reflects relatively recent, post-Pliocene biogeographical patterns; probably older patterns are involved as well. The eastern coast of the Yucatan is the most recently colonized by cyclopine copepods. Most of the genera are linked with South American forms, and the Nearctic influence is weakly represented. This group has no marine relatives, but there is evidence of vicariant events involving cave-dwelling forms. [source] Short-term epidemic dynamics in the Cakile maritima,Alternaria brassicicola host,pathogen associationJOURNAL OF ECOLOGY, Issue 5 2001Peter H. Thrall Summary 1Studies combining within- and among-population processes are crucial for understanding ecological and co-evolutionary dynamics in host,pathogen interactions. We report on work over an 18-month period involving multiple beach populations of the plant Cakile maritima and its fungal pathogen Alternaria brassicicola along the south-east coast of Australia. 2Results from permanent transects replicated on several beaches show that disease incidence and prevalence vary significantly with plant age, class and distance from the sea, as well as time during the season. Plant density is also positively related to disease levels. 3Results from three subregions indicate that disease persistence depends on survival of infected plants behind the foredunes of protected beaches. Population extinction was more likely on beaches with greater wind exposure and sea access, with the latter also related to colonization consistent with the dispersal of Cakile seeds via ocean currents. 4Although disease dynamics during the epidemic were similar across subregions, the severity of the epidemic varied significantly among these areas, suggesting that large-scale environmental factors may influence the timing and development of the epidemic. 5Estimates of synchrony in disease dynamics indicated that populations within a subregion were significantly correlated with respect to epidemic development. There was, however, no evidence for spatial synchrony in disease dynamics based on among-population covariances in disease prevalence and interbeach distances. Populations within a subregion were thus often at quite different phases of the epidemic at any given time. [source] Double Oestrogen Receptor , and , Knockout Mice Reveal Differences in Neural Oestrogen-Mediated Progestin Receptor Induction and Female Sexual BehaviourJOURNAL OF NEUROENDOCRINOLOGY, Issue 10 2003A. E. Kudwa Abstract To test the hypothesis that oestrogen receptor , (ER,) and ER, act together to mediate the actions of oestrogen in the ventromedial hypothalamus (VMH), we used mice with single or double knockout mutations of the ER, and ER, genes. Ovariectomized mice were implanted with 17,-oestradiol and killed 5 days later. Oestradiol treatment promoted progestin receptor (PR)-immunoreactivity (-ir) in the VMH of all genotypes, but was maximal in brains of wild-type and ER,KO females. Analysis of specific VMH subregions revealed that PR-ir induction was limited to the caudal VMH in ER,KO and ER,,KO mice. In the rostral VMH, oestradiol only induced PR-ir in wild-type and ER,KO mice, and the number of PR-ir neurones in this region was greater in ER,KO than wild-type females. Next, we tested the ability of a dopamine agonist and progesterone to facilitate sexual behaviour in females lacking functional ER,, ER,, or both receptors. Ovariectomized mice were implanted with oestradiol, and tested for sexual behaviour three times after administration of the dopamine agonist, apomorphine, followed by two tests concurrent with progesterone treatment and a final test with just apomorphine treatment. ER,KO and ER,,KO females failed to display lordosis under any testing conditions, while ER,KO females exhibited lordosis behaviour equal to that of wild-type females. Our data show that a subpopulation of PR-ir neurones is induced by oestradiol in the caudal VMH of female mice lacking both ER, and ER, genes. We hypothesize that this action of oestradiol is either mediated by a novel ER or by the mutant portion of the AF2 subregion of the ER, gene present in ER,KO brain. However, despite the presence of PR in VMH, females lacking a functional ER, gene do not display sexual behaviour, via either ligand-dependent or -independent activation. [source] Protein phosphatase 2A,negative regulation of the protective signaling pathway of Ca2+/CaM-dependent ERK activation in cerebral ischemiaJOURNAL OF NEUROSCIENCE RESEARCH, Issue 12 2008Jie Zhao Abstract Extracellular-signal-regulated kinase (ERK) undergoes rapid inactivation following the intense activation evoked by cerebral ischemia and reperfusion. However, the precise mechanism of this inactivation has not been elucidated. To investigate how phosphatases regulate the ERK cascade following ischemia, the PP2A inhibitors cantharidin and okadaic acid were administrated to the CA1 subregion of the rat hippocampus. The resulting sustained ERK activity implies that PP2A is a major phosphatase contributing to the rapid inactivation, but not activation, of ERK following cerebral ischemia. The increase in PP2A activity induced by ceramide has a weak effect on the activation of Raf via dephosphorylation of Ser259 in response to ischemia. In contrast, ketamine (Keta) and cyclosporine A (CsA), two chemicals that block calcium signal in ischemia, decrease ERK activity by blocking Raf dephosphorylation of Ser259. We also observed that activation of an upstream protein, Ras-GRF, leads to calcium/calmodulin-dependent activation of the ERK signaling cascade in response to ischemic stimuli. In addition, the activity of cyclic AMP response element-binding protein (CREB) and estrogen receptor , (ER,), target proteins of ERK and protective elements against ischemic lesion, parallels the activity of ERK. These data indicate that PP2A plays a significant role in blocking the protective effect induced by the ERK kinase pathway and that fast inactivation of ERK is the result of cross talk between calcium/calmodulin-dependent, positively regulated signal cascades and a ceramide-dependent negative signaling pathway. © 2008 Wiley-Liss, Inc. [source] Differential Effects of Chronic Ethanol Consumption and Withdrawal on Homer/Glutamate Receptor Expression in Subregions of the Accumbens and Amygdala of P RatsALCOHOLISM, Issue 11 2009Ilona Obara Background:, Homer proteins are constituents of scaffolding complexes that regulate the trafficking and function of central Group1 metabotropic glutamate receptors (mGluRs) and N -methyl- d -aspartate (NMDA) receptors. Research supports the involvement of these proteins in ethanol-induced neuroplasticity in mouse. In this study, we examined the effects of short versus long-term withdrawal from chronic ethanol consumption on Homer and glutamate receptor protein expression within striatal and amygdala subregions of selectively bred, alcohol-preferring P rats. Methods:, For 6 months, male P rats had concurrent access to 15% and 30% ethanol solutions under intermittent (IA: 4 d/wk) or continuous (CA: 7 d/wk) access conditions in their home cage. Rats were killed 24 hours (short withdrawal: SW) or 4 weeks (long withdrawal: LW) after termination of ethanol access, subregions of interest were micropunched and tissue processed for detection of Group1 mGluRs, NR2 subunits of the NMDA receptor and Homer protein expression. Results:, Within the nucleus accumbens (NAC), limited changes in NR2a and NR2b expression were detected in the shell (NACsh), whereas substantial changes were observed for Homer2a/b, mGluRs as well as NR2a and NR2b subunits in the core (NACc). Within the amygdala, no changes were detected in the basolateral subregion, whereas substantial changes, many paralleling those observed in the NACc, were detected in the central nucleus (CeA) subregion. In addition, most of the changes observed in the CeA, but not NACc, were present in both SW and LW rats. Conclusions:, Overall, these subregion specific, ethanol-induced increases in mGluR/Homer2/NR2 expression within the NAC and amygdala suggest changes in glutamatergic plasticity had taken place. This may be a result of learning and subsequent memory formation of ethanol's rewarding effects in these brain structures, which may, in part, mediate the chronic relapsing nature of alcohol abuse. [source] Impacts of Alternative Manure Application Rates on Texas Animal Feeding Operations: A Macro Level Analysis,JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION, Issue 3 2008E. Osei Abstract:, An integrated economic and environmental modeling system was developed for evaluating agro-environmental policies and practices implemented on large scales. The modeling system, the Comprehensive Economic and Environmental Optimization Tool-Macro Modeling System (CEEOT-MMS), integrates the Farm-level Economic Model (FEM) and the Agricultural Policy Environmental eXtender (APEX) model, as well as national databases and clustering and aggregation algorithms. Using micro simulations of statistically derived representative farms and subsequent aggregation of farm-level results, a wide range of agricultural best management practices can be investigated within CEEOT-MMS. In the present study, CEEOT-MMS was used to evaluate the economic and water quality impacts of nitrogen (N) and phosphorus (P) based manure application rates when implemented on all animal feeding operations in the State of Texas. Results of the study indicate that edge-of-field total P losses can be reduced by about 0.8 kg/ha/year or 14% when manure applications are calibrated to supply all of the recommended crop P requirements from manure total P sources only, when compared to manure applications at the recommended crop N agronomic rate. Corresponding economic impacts are projected to average a US$4,800 annual cost increase per farm. Results are also presented by ecological subregion, farm type, and farm size categories. [source] Modelling species diversity through species level hierarchical modellingJOURNAL OF THE ROYAL STATISTICAL SOCIETY: SERIES C (APPLIED STATISTICS), Issue 1 2005Alan E. Gelfand Summary., Understanding spatial patterns of species diversity and the distributions of individ-ual species is a consuming problem in biogeography and conservation. The Cape floristic region of South Africa is a global hot spot of diversity and endemism, and the Protea atlas project, with about 60 000 site records across the region, provides an extraordinarily rich data set to model patterns of biodiversity. Model development is focused spatially at the scale of 1, grid cells (about 37 000 cells total for the region). We report on results for 23 species of a flowering plant family known as Proteaceae (of about 330 in the Cape floristic region) for a defined subregion. Using a Bayesian framework, we developed a two-stage, spatially explicit, hierarchical logistic regression. Stage 1 models the potential probability of presence or absence for each species at each cell, given species attributes, grid cell (site level) environmental data with species level coefficients, and a spatial random effect. The second level of the hierarchy models the probability of observing each species in each cell given that it is present. Because the atlas data are not evenly distributed across the landscape, grid cells contain variable numbers of sampling localities. Thus this model takes the sampling intensity at each site into account by assuming that the total number of times that a particular species was observed within a site follows a binomial distribution. After assigning prior distributions to all quantities in the model, samples from the posterior distribution were obtained via Markov chain Monte Carlo methods. Results are mapped as the model-estimated probability of presence for each species across the domain. This provides an alternative to customary empirical ,range-of-occupancy' displays. Summing yields the predicted richness of species over the region. Summaries of the posterior for each environmental coefficient show which variables are most important in explaining the presence of species. Our initial results describe biogeographical patterns over the modelled region remarkably well. In particular, species local population size and mode of dispersal contribute significantly to predicting patterns, along with annual precipitation, the coefficient of variation in rainfall and elevation. [source] Ecological implications of Fulbe pastoralism in southwestern NigeriaLAND DEGRADATION AND DEVELOPMENT, Issue 5 2003Akin M. Omotayo Abstract The study used a combination of ethno-social surveys and Geographical Information Systems (GIS) to assess 651 pastoral households and their land use under agropastoral production systems in Ogun State, Nigeria. Yields of arable crops on agropastoralists' fields were generally low. Livestock productivity was similar on all parameters to levels in comparable contexts elsewhere across the West African subregion, but generally below possible potentials and on-farm research findings. Pastoral households' activities presently influence between 221,km2 and 523,km2 of land in Ogun State. Pastoral grazing orbits extended beyond administrative boundaries, causing potential conflicts between local crop farmers and agropatoralists. Much of the land-cover has been altered considerably around the areas of pastoral household settlements compared with the situation 20 years ago. It was concluded that a form of intervention was needed that would guarantee sustainability of the land-use system. Copyright © 2003 John Wiley & Sons, Ltd. [source] An interpolated spatial images method for the analysis of multilayered shielded microwave circuitsMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 9 2008J. S. Gómez-Díaz Abstract In this article, an efficient interpolation method is presented to compute the Green's function associated with electrical sources, when they are placed inside cylindrical cavities. The interpolation scheme is formulated in the frame of the spatial images technique recently developed. The original idea was to calculate, for every location of a point electric source, the complex values of the electric dipole and charge images, placed outside the cavity, to impose the appropriate boundary conditions for the potentials. To considerably reduce the computational cost of the original technique, a simple interpolation method is proposed to obtain the complex values of the images for any source location. To do that, a rectangular spatial subdivision inside the cavity is proposed. Each new subregion is controlled by means of the exact image values obtained when the source is placed at the four corners of the region. The key idea is to use a bilinear interpolation to obtain the image complex values when the source is located anywhere inside this subregion. The interpolated images provide the Green's functions of the new source positions fast, and with high accuracy. This new approach can be directly applied to analyze printed planar filters. Two examples with CPU time comparisons are provided, showing the high accuracy and computational gain achieved with the technique just derived. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2294,2300, 2008; Published online in Wiley InterScience (www.interscience.wiley.com).DOI 10.1002/mop.23683 [source] The Millennium Galaxy Catalogue: a census of local compact galaxiesMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 4 2006J. Liske ABSTRACT We use the Millennium Galaxy Catalogue (MGC) to study the effect of compact galaxies on the local field galaxy luminosity function (LF). Here, we observationally define as ,compact' galaxies that are too small to be reliably distinguished from stars using a standard star,galaxy separation technique. In particular, we estimate the fraction of galaxies that are misclassified as stars due to their compactness. We have spectroscopically identified all objects to Bmgc= 20 mag in a 1.14-deg2 subregion of the MGC, regardless of morphology. From these data we develop a model of the high surface brightness (SB) incompleteness and estimate that ,1 per cent of galaxies with Bmgc < 20 mag are misclassified as stars, with an upper limit of 2.3 per cent at 95 per cent confidence. However, since the missing galaxies are preferentially sub- L* their effect on the faint end of the LF is substantially amplified: we find that they contribute ,6 per cent to the total LF in the range ,17 < MB < ,14 mag, which raises the faint end slope , by 0.03+0.02,0.01. Their contribution to the total B -band luminosity density is ,2 per cent. Roughly half of the missing galaxies have already been recovered through spectroscopy of morphologically stellar targets selected mainly by colour. We find that the missing galaxies mostly consist of intrinsically small, blue, star forming, sub- L* objects. In combination with the recent results of Driver et al. we have now demonstrated that the MGC is free from both high- and low-SB selection bias for giant galaxies (MB,,17 mag). Dwarf galaxies, on the other hand, are significantly affected by these selection effects. To gain a complete view of the dwarf population will require both deeper and higher-resolution surveys. [source] Burden of disease related to Parkinson's disease in Spain in the year 2000MOVEMENT DISORDERS, Issue 11 2005Esther Cubo MD Abstract We measured the burden caused by Parkinson's disease (PD) in Spain during the year 2000 and compared it against PD burden worldwide and in the European A subregion. Burden of disease (BoD) is an important factor in health policy. Disability-adjusted life years (DALY) as a measure of BoD is the result of adding years of life lost (YLL) and years lived with disability (YLD). The burden of PD (BPD) has not been studied in Spain. YLL were obtained from the Spanish death certificates and YLD from the estimated number of incident PD cases and the average PD duration. PD disability was calculated, using the Disability Weights for Diseases in the Netherlands. Prior PD DALY data for Europe and the world were obtained from the 2001 World Health Organization World Health Report. A discount rate of 3% and age-weighting modulation factor with K = 1 were used. In Spain, PD generated 67,582 DALY, comprising 6,351 (9.4%) YLL and 61,231 (90.6%) YLD. Most PD DALY (57.5%) occurred in the population 60 to 74 years of age. When PD DALY estimates were adjusted using the world population in 2000, Spain registered a PD DALY rate of 84 per 100,000 population, higher than both the world and European A subregion rates (24 and 35 per 100,000 population, respectively). PD burden in Spain in 2000 was high, with disability being the major contributing factor. Although BPD in Spain was greater than both world and European A subregion BPD, these differences should nevertheless be interpreted with caution. © 2005 Movement Disorder Society [source] Numerical solution of thermal convection problems using the multidomain boundary element methodNUMERICAL METHODS FOR PARTIAL DIFFERENTIAL EQUATIONS, Issue 4 2002W. F. Florez Abstract The multidomain dual reciprocity method (MD-DRM) has been effectively applied to the solution of two-dimensional thermal convection problems where the momentum and energy equations govern the motion of a viscous fluid. In the proposed boundary integral method the domain integrals are transformed into equivalent boundary integrals by the dual reciprocity approach applied in a subdomain basis. On each subregion or domain element the integral representation formulas for the velocity and temperature are applied and discretised using linear continuous boundary elements, and the equations from adjacent subregions are matched by additional continuity conditions. Some examples showing the accuracy, the efficiency and flexibility of the proposed method are presented. © 2002 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 18: 469,489, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/num.10016 [source] Longitudinal weight gain of immunized infants and toddlers in Moroto District, Uganda (Karamoja subregion)AMERICAN JOURNAL OF HUMAN BIOLOGY, Issue 1 2010Sandra Gray This study examines longitudinal weight gain of a sample of 123 immunized children from Moroto District, northeast Uganda. The weight data were combined from two sources: (1) anthropometric examinations carried out between 1998 and 2004 by a research team from the University of Kansas, and (2) weights recorded on children's immunization records by local health care practitioners. Our findings conform generally to the pattern described in previous studies in this as well as other pastoralist populations in sub-Sahara. Relative to international standards, the weight-for-age status of Karimojong children was best during the first 3 months of infancy. Noticeable declines in weight velocity occurred in the fourth month and after the sixth month. Weight gain was static after the second year, when upward of 40% of children were clinically underweight. Factors influencing weight gain in this sample include immunization status and maternal height, weight, and parity, but these effects explain relatively little of the variance in weight gain. We conclude that immunization is not sufficient to buffer Karimojong children from multiple stressors during teething and weaning. Of these, the practice of canine follicle extraction (CFE) is of most interest, although its effects in this study are ambiguous. The data also are suggestive of variability in the pattern of weight gain between closely spaced birth cohorts. This finding may be of particular importance for the interpretation of growth patterns described for other pastoralist populations in sub-Saharan Africa. Am. J. Hum. Biol. 2010. © 2009 Wiley-Liss, Inc. [source] Smaller amygdala is associated with anxiety in patients with panic disorderPSYCHIATRY AND CLINICAL NEUROSCIENCES, Issue 3 2009Fumi Hayano phd Aims:, Anxiety a core feature of panic disorder, is linked to function of the amygdala. Volume alterations in the brain of patients with panic disorder have previously been reported, but there has been no report of amygdala volume association with anxiety. Methods:, Volumes of hippocampus and amygdala were manually measured using magnetic resonance imaging obtained from 27 patients with panic disorder and 30 healthy comparison subjects. In addition the amygdala was focused on, applying small volume correction to optimized voxel-based morphometry (VBM). State,Trait Anxiety Inventory and the NEO Personality Inventory Revised were also used to evaluate anxiety. Results:, Amygdala volumes in both hemispheres were significantly smaller in patients with panic disorder compared with control subjects (left: t = ,2.248, d.f. = 55, P = 0.029; right: t = ,2.892, d.f. = 55, P = 0.005). VBM showed that structural alteration in the panic disorder group occurred on the corticomedial nuclear group within the right amygdala (coordinates [x,y,z (mm)]: [26,,6,,16], Z score = 3.92, family-wise error-corrected P = 0.002). The state anxiety was negatively correlated with the left amygdala volume in patients with panic disorder (r = ,0.545, P = 0.016). Conclusions:, These findings suggested that the smaller volume of the amygdala may be associated with anxiety in panic disorder. Of note, the smaller subregion in the amygdala estimated on VBM could correspond to the corticomedial nuclear group including the central nucleus, which may play a crucial role in panic attack. [source] Geographic origin of southern Brazilian wines by carbon and oxygen isotope analysesRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 20 2010Laurien Adami We present a method that can differentiate between the varieties of grapes and the vintages of wines and show the relationship between the grapes, the wine and the geographic location. The place of origin and its geographic and climatic characteristics were determined by the isotopic ratios, 13C/12C of the ethanol and 18O/16O of the water content of wine (wine water), for southern Brazil wines. The producing subregions of Pinto Bandeira, Vale dos Vinhedos and Nova Pádua showed differences in the temperature, rainfall and humidity conditions used for the production under microvinification conditions of Merlot and Cabernet Sauvignon varieties, in the harvests of 2005 and 2006. An isotope ratio mass spectrometer coupled to an elemental analyzer was used to measure the 13C/12C of ethanol and the 18O/16O of wine water. Regardless of the grape variety used, it was possible to determine the subregion through measurement of the ,18O values in both harvests. The altitudes of the different subregions led to statistical differences and demonstrated an influence mainly on the ,18O values of wine water. The ,18O value of wine water was determined to be more selective for the determination of the cultivation subregions than the ,13C value of the ethanol. The altitude and latitude influenced mainly the , 18O values of wine water and the ethanol. The climatic influences are more noteworthy in distinguishing the year of the harvest than the cultivation subregion. Copyright © 2010 John Wiley & Sons, Ltd. [source] Redefining the boundaries of the hippocampal CA2 subfield in the mouse using gene expression and 3-dimensional reconstructionTHE JOURNAL OF COMPARATIVE NEUROLOGY, Issue 1 2005Edward S. Lein Abstract The morphology of neurons in the main divisions of the hippocampal complex allow the easy identification of granule cells in the dentate gyrus and pyramidal cells in the CA1 and CA3 regions of Ammon's horn. However, neurons in the CA2 subfield have been much more difficult to reliably identify. We have recently identified a set of genes whose expression is restricted to either the dentate gyrus, CA1, CA2, or CA3. Here we show that these genes have an essentially nonoverlapping distribution throughout the entire septotemporal extent of the hippocampus. 3-Dimensional reconstruction of serial sections processed for in situ hybridization of mannosidase 1, alpha (CA1), bcl-2-related ovarian killer protein (CA3), and Purkinje cell protein 4 (dentate gyrus + CA2) was used to define the boundaries of each subregion throughout the entire hippocampus. The boundaries observed for these three genes are recapitulated across a much larger set of genes similarly enriched in specific hippocampal subregions. The extent of CA2 defined on the basis of gene expression is somewhat larger than that previously described on the basis of structural anatomical criteria, particularly at the rostral pole of the hippocampus. These results indicate that, at least at the molecular level, there are robust, consistent genetic boundaries between hippocampal subregions CA1, CA2, CA3, and the dentate gyrus, allowing a redefinition of their boundaries in order to facilitate functional studies of different neuronal subtypes in the hippocampus. J. Comp. Neurol. 485:1,10, 2005. © 2005 Wiley-Liss, Inc. [source] Structure, function and disease susceptibility of the bovine major histocompatibility complexANIMAL SCIENCE JOURNAL, Issue 2 2006Shin-Nosuke TAKESHIMA ABSTRACT The major histocompatibility complex (MHC) of cattle is known as the bovine leukocyte antigen (BoLA) and is located on chromosome 23. BoLA has been linked to variation in resistance to disease including bovine leukemia virus-induced lymphoma and mastitis. Moreover, BoLA appears to influence other traits such as milk yield, growth and reproduction, which are not often measured in humans, and variations in individual immune response to antigen. The BoLA appears to be organized in a similar way to the MHC region in humans, but there are notable differences. A major rearrangement within the class II region has led to the division of the BoLA into two distinct subregions of chromosome 23 separated by about a third of the chromosome's length. The class IIa subregion contains functionally expressed DR and DQ genes, while the class IIb subregion contains the genes of undefined status such as DYA, DYB, DMA, DMB, DOB, DOA, TAP1, TAP2, LAP2 and LMP7. In addition, one pair of human class II genes (DP) does not appear to have an equivalent in cattle, and there is one pair of DY genes that seem to be found only cattle, sheep and goats. In humans, three classical, polymorphic class I genes (HLA-A, -B and -C,) are each present on all haplotypes. However, in cattle, none of the four (or more) classical class-I genes identified are consistently expressed, and haplotypes differ from one to another in both the gene number and composition. These variations in both class I and II are likely to play an important role in cattle immune responses. This review summarizes current knowledge of the structural and functional features and disease association of BoLA genes. [source] Improving the assessment of species compositional dissimilarity in a priori ecological classifications: evaluating map scale, sampling intensity and improvement in a hierarchical classificationAPPLIED VEGETATION SCIENCE, Issue 4 2010B.E. Lawson Abstract Question: Can species compositional dissimilarity analyses be used to assess and improve the representation of biodiversity patterns in a priori ecological classifications? Location: The case study examined the northern-half of the South-east Queensland Bioregion, eastern Australia. Methods: Site-based floristic presence,absence data were used to construct species dissimilarity matrices (Kulczynski metric) for three levels of Queensland's bioregional hierarchy , subregions (1:500 000 scale), land zones (1:250 000 scale) and regional ecosystems (1:100 000 scale). Within- and between-class dissimilarities were compiled for each level to elucidate species compositional patterns. Randomized subsampling was used to determine the minimum site sampling intensity for each hierarchy level, and the effects of lumping and splitting illustrated for several classes. Results: Consistent dissimilarity estimates were obtained with five or more sites per regional ecosystem, 10 or more sites per land zone, and more than 15 sites per subregion. On average, subregions represented 4% dissimilarity in floristic composition, land zones approximately 10%, and regional ecosystems over 19%. Splitting classes with a low dissimilarity increased dissimilarity levels closer to average, while merging ecologically similar classes with high dissimilarities reduced dissimilarity levels closer to average levels. Conclusions: This approach demonstrates a robust and repeatable means of analysing species compositional dissimilarity, determining site sampling requirements for classifications and guiding decisions about ,lumping' or ,splitting' of classes. This will allow more informed decisions on selecting and improving classifications and map scales in an ecologically and statistically robust manner. [source] | ||||||||||||||||||||||||||||||||||||||||||||||