bluuebunny/crossref_metadata_2025 huggingface dataset:
Metabotropic Glutamate Receptor Subtype 8 in the Amygdala Modulates Thermal Threshold, Neurotransmitter Release, and Rostral Ventromedial Medulla Cell Activity in Inflammatory Pain
Authors: Palazzo Enza , Marabese Ida , Soukupova Marie , Luongo Livio , Boccella Serena , Giordano Catia , de Novellis Vito , Rossi Francesca , Maione Sabatino
Published: March 2011

The amygdala is a crucial area in controlling the threshold of pain and its emotional component. The present study has evaluated the effect of a metabotropic glutamate 8 receptor (mGluR8) stimulation in the central nucleus of the amygdala (CeA) on the thermoceptive threshold and on CeA serotonin (5-HT), glutamate (Glu), and GABA release in normal and carrageenan-induced inflammatory pain conditions in rats. Furthermore, the activity of rostral ventromedial medulla (RVM) putative “pronociceptive” ON and “antinociceptive” OFF cells has been evaluated. (S)-3,4-Dicarboxyphenylglycine [(S)-3,4-DCPG], a selective mGluR8 agonist, administered into the CeA, did not change 5-HT, Glu, and GABA release, or the thermoceptive threshold, nor did it modify the activity of ON and OFF cells of the RVM in normal animals. In rats treated with carrageenan, intra-CeA (S)-3,4-DCPG perfusion produced antinociception, and increased 5-HT and Glu, whereas it decreased GABA release. Intra-CeA (S)-3,4-DCPG inhibited ON and increased OFF cell activities. Furthermore, an increase inmGluR8gene, protein, and staining, the latter being associated with vesicular GABA transporter-positive profiles, has been found in the CeA after carrageenan-induced inflammatory pain. These results show that stimulation of mGluR8, which was overexpressed within the CeA in inflammatory pain conditions, inhibits nociceptive behavior. Such an effect is associated with an increase in 5-HT and Glu release, a decrease in GABA, and the inhibition of ON- and the stimulation of OFF-cell activities within RVM.
Sleep Deprivation Amplifies Reactivity of Brain Reward Networks, Biasing the Appraisal of Positive Emotional Experiences
Authors: Gujar Ninad , Yoo Seung-Schik , Hu Peter , Walker Matthew P.
Published: March 2011

Appropriate interpretation of pleasurable, rewarding experiences favors decisions that enhance survival. Conversely, dysfunctional affective brain processing can lead to life-threatening risk behaviors (e.g., addiction) and emotion imbalance (e.g., mood disorders). The state of sleep deprivation continues to be associated with maladaptive emotional regulation, leading to exaggerated neural and behavioral reactivity to negative, aversive experiences. However, such detrimental consequences are paradoxically aligned with the perplexing antidepressant benefit of sleep deprivation, elevating mood in a proportion of patients with major depression. Nevertheless, it remains unknown how sleep loss alters the dynamics of brain and behavioral reactivity to rewarding, positive emotional experiences. Using functional magnetic resonance imaging (fMRI), here we demonstrate that sleep deprivation amplifies reactivity throughout human mesolimbic reward brain networks in response to pleasure-evoking stimuli. In addition, this amplified reactivity was associated with enhanced connectivity in early primary visual processing pathways and extended limbic regions, yet with a reduction in coupling with medial frontal and orbitofrontal regions. These neural changes were accompanied by a biased increase in the number of emotional stimuli judged as pleasant in the sleep-deprived group, the extent of which exclusively correlated with activity in mesolimbic regions. Together, these data support a view that sleep deprivation not only is associated with enhanced reactivity toward negative stimuli, but imposes a bidirectional nature of affective imbalance, associated with amplified reward-relevant reactivity toward pleasure-evoking stimuli also. Such findings may offer a neural foundation on which to consider interactions between sleep loss and emotional reactivity in a variety of clinical mood disorders.
Episodic Memory Retrieval, Parietal Cortex, and the Default Mode Network: Functional and Topographic Analyses
Authors: Sestieri Carlo , Corbetta Maurizio , Romani Gian Luca , Shulman Gordon L.
Published: March 2011

The default mode network (DMN) is often considered a functionally homogeneous system that is broadly associated with internally directed cognition (e.g., episodic memory, theory of mind, self-evaluation). However, few studies have examined how this network interacts with other networks during putative “default” processes such as episodic memory retrieval. Using functional magnetic resonance imaging, we investigated the topography and response profile of human parietal regions inside and outside the DMN, independently defined using task-evoked deactivations and resting-state functional connectivity, during episodic memory retrieval. Memory retrieval activated posterior nodes of the DMN, particularly the angular gyrus, but also more anterior and dorsal parietal regions that were anatomically separate from the DMN. The two sets of parietal regions showed different resting-state functional connectivity and response profiles. During memory retrieval, responses in DMN regions peaked sooner than non-DMN regions, which in turn showed responses that were sustained until a final memory judgment was reached. Moreover, a parahippocampal region that showed strong resting-state connectivity with parietal DMN regions also exhibited a pattern of task-evoked activity similar to that exhibited by DMN regions. These results suggest that DMN parietal regions directly supported memory retrieval, whereas non-DMN parietal regions were more involved in postretrieval processes such as memory-based decision making. Finally, a robust functional dissociation within the DMN was observed. Whereas angular gyrus and posterior cingulate/precuneus were significantly activated during memory retrieval, an anterior DMN node in medial prefrontal cortex was strongly deactivated. This latter finding demonstrates functional heterogeneity rather than homogeneity within the DMN during episodic memory retrieval.
Recovery from μ-Opioid Receptor Desensitization after Chronic Treatment with Morphine and Methadone
Authors: Quillinan Nidia , Lau Elaine K. , Virk Michael , von Zastrow Mark , Williams John T.
Published: March 2011

Chronic treatment with morphine results in a decrease in μ-opioid receptor sensitivity, an increase in acute desensitization, and a reduction in the recovery from acute desensitization in locus ceruleus neurons. With acute administration, morphine is unlike many other opioid agonists in that it does not mediate robust acute desensitization or induce receptor trafficking. This study compares μ-opioid receptor desensitization and trafficking in brain slices taken from rats treated for 6–7 d with a range of doses of morphine (60, 30, and 15 mg · kg−1· d−1) and methadone (60, 30, and 5 mg · kg−1· d−1) applied by subcutaneous implantation of osmotic minipumps. Mice were treated with 45 mg · kg−1· d−1. In morphine-treated animals, recovery from acute [Met]5enkephalin-induced desensitization and receptor recycling was diminished. In contrast, recovery and recycling were unchanged in slices from methadone-treated animals. Remarkably the reduced recovery from desensitization and receptor recycling found in slices from morphine-treated animals were not observed in animals lacking β-arrestin-2. Furthermore, pharmacological inhibition of G-protein receptor kinase 2 (GRK2), although not affecting the ability of [Met]5enkephalin to induce desensitization, acutely reversed the delay in recovery from desensitization produced by chronic morphine treatment. These results characterize a previously unidentified function of the GRK/arrestin system in mediating opioid regulation in response to chronic morphine administration. They also suggest that the GRK/arrestin system, rather than serving as a primary mediator of acute desensitization, controls recovery from desensitization by regulating receptor reinsertion to the plasma membrane after chronic treatment with morphine. The sustained GRK/arrestin-dependent desensitization is another way in which morphine and methadone are distinguished.
Constancy and Variability in the Output of a Central Pattern Generator
Authors: Norris Brian J. , Wenning Angela , Wright Terrence Michael , Calabrese Ronald L.
Published: March 2011

Experimental and corresponding modeling studies have demonstrated a twofold to fivefold variation of intrinsic and synaptic parameters across animals, whereas functional output is maintained. These studies have led to the hypothesis that correlated, compensatory changes in particular parameters can at least partially explain the biological variability in parameters. Using the leech heartbeat central pattern generator (CPG), we selected three different segmental motor neurons that fire in a functional phase progression but receive input from the same four premotor interneurons. Previous work suggested that the phase progression arises because the pattern of relative strength of the four inputs varies systematically across the segmental motor neurons. Nevertheless, there was considerable animal-to-animal variation in the absolute strengths of these connections. We tested the hypothesis that functional output is maintained in the face of variation in the absolute strength of connections because relative strengths onto particular motor neurons are maintained. We found that relative strength is not strictly maintained across animals even as functional output is maintained, and animal-to-animal variations in relative strength of particular inputs do not correlate strongly with output phase. In parallel with this variation in synaptic strength, the firing phase of the premotor inputs to these motor neurons varies considerably across individuals. We conclude that the number (four) of inputs to each motor neuron, which each vary in strength, and the phase diversity of the temporal pattern of input from the CPG diminish the influence of individual inputs. We hypothesize that each animal arrives at a unique solution for how the network produces functional output.
Fast and Reversible Stimulation of Astrocytic Glycolysis by K+and a Delayed and Persistent Effect of Glutamate
Authors: Bittner Carla X. , Valdebenito Rocío , Ruminot Iván , Loaiza Anitsi , Larenas Valeria , Sotelo-Hitschfeld Tamara , Moldenhauer Hans , San Martín Alejandro , Gutiérrez Robin , Zambrano Marilyn , Barros L. Felipe
Published: March 2011

Synaptic activity is followed within seconds by a local surge in lactate concentration, a phenomenon that underlies functional magnetic resonance imaging and whose causal mechanisms are unclear, partly because of the limited spatiotemporal resolution of standard measurement techniques. Using a novel Förster resonance energy transfer-based method that allows real-time measurement of the glycolytic rate in single cells, we have studied mouse astrocytes in search for the mechanisms responsible for the lactate surge. Consistent with previous measurements with isotopic 2-deoxyglucose, glutamate was observed to stimulate glycolysis in cultured astrocytes, but the response appeared only after a lag period of several minutes. Na+overloads elicited by engagement of the Na+-glutamate cotransporter withd-aspartate or application of the Na+ionophore gramicidin also failed to stimulate glycolysis in the short term. In marked contrast, K+stimulated astrocytic glycolysis by fourfold within seconds, an effect that was observed at low millimolar concentrations and was also present in organotypic hippocampal slices. After removal of the agonists, the stimulation by K+ended immediately but the stimulation by glutamate persisted unabated for >20 min. Both stimulations required an active Na+/K+ATPase pump. By showing that small rises in extracellular K+mediate short-term, reversible modulation of astrocytic glycolysis and that glutamate plays a long-term effect and leaves a metabolic trace, these results support the view that astrocytes contribute to the lactate surge that accompanies synaptic activity and underscore the role of these cells in neurometabolic and neurovascular coupling.
The Importance of Being Variable
Authors: Garrett Douglas D. , Kovacevic Natasa , McIntosh Anthony R. , Grady Cheryl L.
Published: March 2011

New work suggests that blood oxygen level-dependent (BOLD) signal variability can be a much more powerful index of human age than mean activation, and that older brains are actually less variable than younger brains. However, little is known of how BOLD variability and task performance may relate. In the current study, we examined BOLD variability in relation to age, and reaction time speed and consistency in healthy younger (20–30 years) and older (56–85 years) adults on three cognitive tasks (perceptual matching, attentional cueing, and delayed match-to-sample). Results indicated that younger, faster, and more consistent performers exhibited significantly higher brain variability across tasks, and showed greater variability-based regional differentiation compared with older, poorer-performing adults. Also, when we compared brain variability- and typical mean-based effects, the respective spatial patterns were essentially orthogonal across brain measures, and any regions that did overlap were largely opposite in directionality of effect. These findings help establish the functional basis of BOLD variability, and further support the statistical and spatial differentiation between BOLD variability and BOLD mean. We thus argue that the precise nature of relations between aging, cognition, and brain function is underappreciated by using mean-based brain measures exclusively.
Comparison of Strategy Signals in the Dorsolateral and Orbital Prefrontal Cortex
Authors: Tsujimoto Satoshi , Genovesio Aldo , Wise Steven P.
Published: March 2011

Abstract behavior-guiding rules and strategies allow monkeys to avoid errors in rarely encountered situations. In the present study, we contrasted strategy-related neuronal activity in the dorsolateral prefrontal cortex (PFdl) and the orbital prefrontal cortex (PFo) of rhesus monkeys. On each trial of their behavioral task, the monkeys responded to a foveal visual cue by making a saccade to one of two spatial targets. One response required a leftward saccade, the other required a saccade of equal magnitude to the right. The cues instructed the monkeys to follow one of two response strategies: to stay with their most recent successful response or to shift to the alternative response. Neurons in both areas encoded the stay and shift strategies after the cue appeared, but there were three major differences between the PFo and the PFdl: (1) many strategy-encoding cells in PFdl also encoded the response (left or right), but few, if any, PFo cells did so; (2) strategy selectivity appeared earlier in PFo than in PFdl; and (3) on error trials, PFo neurons encoded the correct strategy—the one that had been cued but not implemented—whereas in PFdl the strategy signals were weak or absent on error trials. These findings indicate that PFo and PFdl both contribute to behaviors guided by abstract response strategies, but do so differently, with PFo encoding a strategy and PFdl encoding a response based on a strategy.
Intrinsic Bioenergetic Properties and Stress Sensitivity of Dopaminergic Synaptosomes
Authors: Choi Sung W. , Gerencser Akos A. , Lee Donna W. , Rajagopalan Subramanian , Nicholls David G. , Andersen Julie K. , Brand Martin D.
Published: March 2011

Dopaminergic neurons of the substantia nigra pars compacta are defective in Parkinson's disease, but the specificity of this dysfunction is not understood. One hypothesis is that mitochondrial bioenergetic capacity is intrinsically lower in striatal dopaminergic presynaptic nerve varicosities, making them unusually susceptible to inhibition of electron transport by oxidative damage. To test this hypothesis, we separated isolated synaptosomes bearing dopamine transporters using immunomagnetic beads and compared their respiration with that of the residual nondopaminergic synaptosomes. As predicted, dopaminergic synaptosomes from striatum had lower respiratory rates. However, so did dopaminergic synaptosomes from cortex, indicating a lack of the predicted striatal specificity. We used fluorescent probes to analyze the bioenergetic competence of individual synaptosomes in the two fractions. The respiratory differences became nonsignificant when respiration rates were normalized to the number of respiration-competent synaptosomes, suggesting that differences reflected the quality of the different fractions. To circumvent damage induced by synaptosomal separation, we monitored membrane potentials in whole unseparated single synaptosomes using fluorescent imaging, and then identified the dopaminergic subpopulation using a fluorescent dopamine transporter substrate (ASP+[4-(4-diethylaminostyryl)-N-methylpyridinium iodide]). The capacity of dopaminergic and nondopaminergic synaptosomes to maintain plasma membrane and mitochondrial membrane potential under several stresses did not differ. In addition, this capacity did not decline in either subpopulation with age, a risk factor for Parkinson's disease. We conclude that the intrinsic bioenergetic capacities of dopaminergic and nondopaminergic presynaptic synaptosomes from mice do not differ.
Remyelination Is Altered by Bone Morphogenic Protein Signaling in Demyelinated Lesions
Authors: Sabo Jennifer K. , Aumann Tim D. , Merlo Daniel , Kilpatrick Trevor J. , Cate Holly S.
Published: March 2011

Remyelination of the CNS involves the regeneration of mature oligodendrocytes by endogenous oligodendrocyte progenitor cells (OPCs). Previous studies have shown that bone morphogenic proteins (BMPs) inhibit the production of oligodendrocytes in the healthy CNS. However, there is currently no information on the influence of BMP signalingin vivowithin demyelinated lesions of the brain or on subsequent remyelination. Here, we determine a role for BMP signaling in modulating oligodendrogliogenesis and remyelination in the brain following cuprizone-induced demyelination. We identified that BMP signaling is active in oligodendroglia and astrocytes within the demyelinated corpus callosum. Intraventricular infusion of BMP4 into the brains of mice during demyelination increased the proliferation of OPCs and, to a lesser extent, microglia and astrocytes in the corpus callosum. In contrast, infusion of Noggin, an extracellular antagonist of BMP4, increased the density of mature oligodendrocytes in the remyelinating corpus callosum. Additional evidence from myelin staining and electron microscopy indicates there is an increase in remyelinated axons in the corpus callosum of Noggin-infused mice. Thus, inhibition of endogenous BMP signaling during demyelination promotes mature oligodendrocyte regeneration and remyelination.
Lateral Mobility of Presynaptic L-Type Calcium Channels at Photoreceptor Ribbon Synapses
Authors: Mercer Aaron J. , Chen Minghui , Thoreson Wallace B.
Published: March 2011

At most synapses, presynaptic Ca2+channels are positioned near vesicle release sites, and increasing this distance reduces synaptic strength. We examined the lateral membrane mobility of presynaptic L-type Ca2+channels at photoreceptor ribbon synapses of the tiger salamander (Ambystoma tigrinum) retina. Movements of individual Ca2+channels were tracked by coupling quantum dots to an antibody against the extracellular α2δ4Ca2+channel subunit. α2δ4antibodies labeled photoreceptor terminals and colocalized with antibodies to synaptic vesicle glycoprotein 2 and voltage-gated Ca2+channel 1.4 (CaV1.4) α1subunits. The results show that Ca2+channels are dynamic and move within a confined region beneath the synaptic ribbon. The size of this confinement area is regulated by actin and membrane cholesterol. Fusion of nearby synaptic vesicles caused jumps in Ca2+channel position, propelling them toward the outer edge of the confinement domain. Channels rebounded rapidly toward the center. Thus, although CaVchannels are mobile, molecular scaffolds confine them beneath the ribbon to maintain neurotransmission even at high release rates.
NMDA Currents Modulate the Synaptic Input–Output Functions of Neurons in the Dorsal Nucleus of the Lateral Lemniscus in Mongolian Gerbils
Authors: Porres Christian P. , Meyer Elisabeth M. M. , Grothe Benedikt , Felmy Felix
Published: March 2011

Neurons in the dorsal nucleus of the lateral lemniscus (DNLL) receive excitatory and inhibitory inputs from the superior olivary complex (SOC) and convey GABAergic inhibition to the contralateral DNLL and the inferior colliculi. Unlike the fast glycinergic inhibition in the SOC, this GABAergic inhibition outlasts auditory stimulation by tens of milliseconds. Two mechanisms have been postulated to explain this persistent inhibition. One, an “integration-based” mechanism, suggests that postsynaptic excitatory integration in DNLL neurons generates prolonged activity, and the other favors the synaptic time course of the DNLL output itself. The feasibility of the integration-based mechanism was testedin vitroin DNLL neurons of Mongolian gerbils by quantifying the cellular excitability and synaptic input–output functions (IO-Fs). All neurons were sustained firing and generated a near monotonic IO-F on current injections. From synaptic stimulations, we estimate that activation of approximately five fibers, each on average liberating ∼18 vesicles, is sufficient to trigger a single postsynaptic action potential. A strong single pulse of afferent fiber stimulation triggered multiple postsynaptic action potentials. The steepness of the synaptic IO-F was dependent on the synaptic NMDA component. The synaptic NMDA receptor current defines the slope of the synaptic IO-F by enhancing the temporal and spatial EPSP summation. Blocking this NMDA-dependent amplification during postsynaptic integration of train stimulations resulted into a ∼20% reduction of the decay time course of the GABAergic inhibition. Thus, our data show that the NMDA-dependent amplification of the postsynaptic activity contributes to the GABAergic persistent inhibition generated by DNLL neurons.
The Presynaptic Dense Projection of theCaenorhabiditis elegansCholinergic Neuromuscular Junction Localizes Synaptic Vesicles at the Active Zone through SYD-2/Liprin and UNC-10/RIM-Dependent Interactions
Authors: Stigloher Christian , Zhan Hong , Zhen Mei , Richmond Janet , Bessereau Jean-Louis
Published: March 2011

The active zone (AZ) of chemical synapses is a specialized area of the presynaptic bouton in which vesicles fuse with the plasma membrane and release neurotransmitters. Efficient signaling requires synaptic vesicles (SVs) to be recruited, primed, and retained at the AZ, in close proximity to voltage-dependent calcium channels that are activated during presynaptic depolarization. The electron-dense specializations at the AZ might provide a molecular platform for the spatial coordination of these different processes. To investigate this hypothesis, we examined high-resolution three-dimensional models ofCaenorhabditis eleganscholinergic neuromuscular junctions generated by electron tomography. First, we found that SVs are interconnected within the bouton by filaments similar to those described in vertebrates. Second, we resolved the three-dimensional structure of the dense projection centered in the AZ. The dense projection is a more complex structure than previously anticipated, with filaments radiating from a core structure that directly contact SVs in the interior of the bouton as well as SVs docked at the plasma membrane. Third, we investigated the functional correlate of these contacts by analyzing mutants disrupting two key AZ proteins: UNC-10/RIM and SYD-2/liprin. In both mutants, the number of contacts between SVs and the dense projection was significantly reduced. Similar tounc-10mutants, the dependence of SV fusion on extracellular calcium concentration was exacerbated insyd-2mutants when compared with the wild type. Hence, we propose that the dense projection ensures proper coupling of primed vesicles with calcium signaling by retaining them at the AZ via UNC-10/RIM and SYD-2/liprin-dependent mechanisms.
Loss of COUP-TFI Alters the Balance between Caudal Ganglionic Eminence- and Medial Ganglionic Eminence-Derived Cortical Interneurons and Results in Resistance to Epilepsy
Authors: Lodato Simona , Tomassy Giulio Srubek , De Leonibus Elvira , Uzcategui Yoryani G. , Andolfi Gennaro , Armentano Maria , Touzot Audrey , Gaztelu Jose M. , Arlotta Paola , Menendez de la Prida Liset , Studer Michèle
Published: March 2011

In rodents, cortical interneurons originate from the medial ganglionic eminence (MGE) and caudal ganglionic eminence (CGE) according to precise temporal schedules. The mechanisms controlling the specification of CGE-derived interneurons and their role in cortical circuitry are still unknown. Here, we show that COUP-TFI expression becomes restricted to the dorsal MGE and CGE at embryonic day 13.5 in the basal telencephalon. Conditional loss of function of COUP-TFI in subventricular precursors and postmitotic cells leads to a decrease of late-born, CGE-derived, VIP (vasoactive intestinal peptide)- and CR (calretinin)-expressing bipolar cortical neurons, compensated by the concurrent increase of early-born MGE-derived, PV (parvalbumin)-expressing interneurons. Strikingly, COUP-TFI mutants are more resistant to pharmacologically induced seizures, a phenotype that is dependent on GABAergic signaling. Together, our data indicate that COUP-TFI controls the delicate balance between MGE- and CGE-derived cortical interneurons by regulating intermediate progenitor divisions and ultimately affecting the activity of the cortical inhibitory circuitry.
Erk1/2 Inhibit Synaptic Vesicle Exocytosis through L-Type Calcium Channels
Authors: Subramanian Jaichandar , Morozov Alexei
Published: March 2011

L-type calcium channels play only a minor role in basal neurotransmitter release in brain neurons but contribute significantly after induction of plasticity. Very little is known about mechanisms that enable L-type calcium channel participation in neurotransmitter release. Here, using mouse primary cortical neurons, we found that inhibition of Erk1/2 (extracellular signal-regulated kinases 1 and 2) enhanced synaptic vesicle exocytosis by increasing calcium influx through L-type calcium channels. Furthermore, inhibition of Erk1/2 increased the surface fraction of these channels. These findings indicate a novel inhibitory effect of Erk1/2 on synaptic transmission through L-type calcium channels.
Rossellini's Pictorial Histories
Authors: Forgacs David
Published: March 2011

A survey of Roberto Rossellini's filmmaking career with particular emphasis on the continuities and differences between the World War II films of his early career and the later dramatization of an older scientific, religious, and political history.
Religious Dimension in Development Studies
Authors: Loewen Nathan
Published: March 2011

Religion, spirituality and faith are themes gaining interest and prominence in the field of development studies. This “religious turn in development” (Pearson and Tomalin 2008, 49) has gone largely unnoticed by religious studies scholars. The range of current publications on the topic is not produced by self-identified religion scholars. I wish to give an overview of this nascent topic for study in order to suggest how the acumen of religious studies scholars might engage it. I will first make some remarks about the field of international development in order to locate challenges within the ‘religious turn’ within the current IDS discourse. I wish to conclude with some proposals for studying the religious dimensions of international development.
Transformation of the initiates' identities after their initiation into the mysteries of Mithras
Authors: Panagiotidou Olympia
Published: March 2011

This article is a preliminary attempt to investigate the way in which the initiates into the mithraic mysteries experienced a transformation of their identities in the cultic context. This transformation expanded in the wider framework of their lives and determined new, different lines of action. Since the very processes, through which people acquire a sense of themselves and shape their identity, are determined by specific cognitive principles and operations, the investigation of these processes could help us to understand how Mithraists experienced their participation to the mysteries, and the effects that such an experience had in the way in which they perceived themselves. In this perspective the cognitive theory of Mark Johnson about the narrative dimension of human experience is used as a theoretical framework for an understanding of the broader impact of initiation into the mithraic mysteries on the construction of the initiates’ identities.
18F-FDG PET/CT as a Diagnostic Tool in Patients with Extracervical Carcinoma of Unknown Primary Site: A Literature Review
Authors: Moller Anne Kirstine Hundahl , Loft Annika , Berthelsen Anne Kiil , Damgaard Pedersen Karen , Graff Jesper , Christensen Charlotte Birk , Perell Katharina , Petersen Bodil Laub , Daugaard Gedske
Published: March 2011

Background.

Carcinoma of unknown primary (CUP) represents a heterogeneous group of metastatic malignancies for which no primary tumor site can be identified after extensive diagnostic workup. Failure to identify the primary site may negatively influence patient management. The aim of this review was to evaluate 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) as a diagnostic tool in patients with extracervical CUP.

Materials and Methods.

A comprehensive literature search was performed and four publications were identified (involving 152 patients) evaluating 18F-FDG PET/CT in CUP patients with extracervical metastases. All studies were retrospective and heterogeneous in inclusion criteria, study design, and diagnostic workup prior to 18F-FDG PET/CT.

Results.

18F-FDG PET/CT detected the primary tumor in 39.5% of patients with extracervical CUP. The lung was the most commonly detected primary tumor site (∼50%). The pooled estimates of sensitivity, specificity, and accuracy of 18F-FDG PET/CT in the detection of the primary tumor site were 87%, 88%, and 87.5%, respectively.

Conclusions.

The present review of currently available data indicates that 18F-FDG PET/CT might contribute to the identification of the primary tumor site in extracervical CUP. However, prospective studies with more uniform inclusion criteria are required to evaluate the exact value of this diagnostic tool.
Escargots through time: an energetic comparison of marine gastropod assemblages before and after the Mesozoic Marine Revolution
Authors: Finnegan Seth , McClain Craig M. , Kosnik Matthew A. , Payne Jonathan L.
Published: March 2011

The modern structure of marine benthic ecosystems was largely established during the Jurassic and Early Cretaceous (200–100 Ma), a transition that has been termed the Mesozoic Marine Revolution (MMR). Although it has been suggested that the MMR marks an increase in the average energy consumption of marine animal ecosystems, this hypothesis has not been evaluated quantitatively. In this study, we integrate body size and abundance data from the fossil record with physiological data from living representatives to estimate mean per capita metabolic rates of tropical to subtropical assemblages of shallow-marine gastropods—a major component of marine ecosystems throughout the Meso-Cenozoic—both before and after the MMR. We find that mean per capita metabolic rate rose by ∼150% between the Late Triassic and Late Cretaceous and remained relatively stable thereafter. The most important factor governing the increase in metabolic rate was an increase in mean body size. In principle, this size increase could result from secular changes in sampling and taphonomic biases, but these biases are suggested to yield decreases rather than increases in mean size. Considering that post-MMR gastropod diversity is dominated by predators, the net primary production required to supply the energetic needs of the average individual increased by substantially more than 150%. These data support the hypothesis that benthic energy budgets increased during the MMR, possibly in response to rising primary productivity.
Fossil evidence for low gas exchange capacities for Early Cretaceous angiosperm leaves
Authors: Feild Taylor S. , Upchurch Garland R. , Chatelet David S. , Brodribb Timothy J. , Grubbs Kunsiri C. , Samain Marie-Stéphanie , Wanke Stefan
Published: March 2011

The photosynthetic gas exchange capacities of early angiosperms remain enigmatic. Nevertheless, many hypotheses about the causes of early angiosperm success and how angiosperms influenced Mesozoic ecosystem function hinge on understanding the maximum capacity for early angiosperm metabolism. We applied structure-functional analyses of leaf veins and stomatal pore geometry to determine the hydraulic and diffusive gas exchange capacities of Early Cretaceous fossil leaves. All of the late Aptian—early Albian angiosperms measured possessed low vein density and low maximal stomatal pore area, indicating low leaf gas exchange capacities in comparison to modern ecologically dominant angiosperms. Gas exchange capacities for Early Cretaceous angiosperms were equivalent or lower than ferns and gymnosperms. Fossil leaf taxa from Aptian to Paleocene sediments previously identified as putative stem-lineages to Austrobaileyales and Chloranthales had the same gas exchange capacities and possibly leaf water relations of their living relatives. Our results provide fossil evidence for the hypothesis that high leaf gas exchange capacity is a derived feature of later angiosperm evolution. In addition, the leaf gas exchange functions of austrobaileyoid and chloranthoid fossils support the hypothesis that comparative research on the biology of living basal angiosperm lineages reveals genuine signals of Early Cretaceous angiosperm ecophysiology.
Changes in shell durability of common marine taxa through the Phanerozoic: evidence for biological rather than taphonomic drivers
Authors: Kosnik Matthew A. , Alroy John , Behrensmeyer Anna K. , Fürsich Franz T. , Gastaldo Robert A. , Kidwell Susan M. , Kowalewski Michał , Plotnick Roy E. , Rogers Raymond R. , Wagner Peter J.
Published: March 2011

Phanerozoic trends in shell and life habit traits linked to postmortem durability were evaluated for the most common fossil brachiopod, gastropod, and bivalve genera in order to test for changes in taphonomic bias. Using the Paleobiology Database, we tabulated occurrence frequencies of genera for 48 intervals of ∼11 Myr duration. The most frequently occurring genera, cumulatively representing 40% of occurrences in each time bin, were scored for intrinsic durability on the basis of shell size, reinforcement (ribs, folds, and spines), life habit, and mineralogy.

Shell durability is positively correlated with the number of genera in a time bin, but durability traits exhibit different temporal patterns across higher taxa, with notable offsets in the timing of changes in these traits. We find no evidence for temporal decreases in durability that would indicate taphonomic bias at the Phanerozoic scale among commonly occurring genera. Also, all three groups show a remarkable stability in mean shell size through the Phanerozoic, an unlikely pattern if strong size-filtering taphonomic megabiases were affecting the fossil record of shelly faunas. Moreover, small shell sizes are attained in the early Paleozoic in brachiopods and in the latest Paleozoic in gastropods but are steady in bivalves; unreinforced shells are common to all groups across the entire Phanerozoic; organophosphatic and aragonitic shells dominate only the oldest and youngest time bins; and microstructures having high organic content are most common in the oldest time bins.

In most cases, the timing of changes in durability-related traits is inconsistent with a late Mesozoic Marine Revolution. The post-Paleozoic increase in mean gastropod reinforcement occurs in the early Triassic, suggesting either an earlier appearance and expansion of durophagous predators or other drivers. Increases in shell durability hypothesized to be the result of increased predation in the late Mesozoic are not evident in the common genera examined here. Infaunal life habit does increase in the late Mesozoic, but it does not become more common than levels already attained during the Paleozoic, and only among bivalves does the elevated late Mesozoic level persist through the Holocene.

These temporal patterns suggest control on the occurrence of durability-related traits by individual evolutionary histories rather than taphonomic megabiases. Our findings do not mean taphonomic biases are absent from the fossil record, but rather that their effects apparently have had littleneteffect on the relative occurrence of shell traits generally thought to confer higher preservation potential over long time scales.
Demographic Changes and the Gains from Globalisation: An Analysis of Ageing, Capital Flows, and International Trade
Authors: Mérette Marcel , Georges Patrick
Published: March 2011

This paper develops a multi-country overlapping-generations general equilibrium model to gauge the economic impact of demographic changes in the global economy and its transmission effects on different countries. Although severe demographic pressures contribute to significantly lower real GDP per capita across several regions in the world, globalisation through international trade generates an intertemporal gain from trade and a long-lasting improvement in the terms of trade of older OECD countries, which sustains their real consumption per capita (when goods from different geographical origins are assumed to be imperfectly substitutable), while globalisation through capital flows stimulates capital accumulation and growth in younger countries such as India and various parts of the rest of the world. The paper also illustrates that the very distinct demographic projections for China and India might, ceteris paribus, lead to striking divergences in their economic fortune.
Determinants of Investment by the Norwegian Sovereign Wealth Fund: GDP vs. Institutions
Authors: Caner Mehmet , Caner Turanay , Grennes Thomas J.
Published: March 2011

During the current episode of globalization, capital has flown primarily to high income countries. Attempts to explain this “Lucas Paradox” have focused on the quality of institutions. We analyze data from a major institutional investor, the Norwegian Sovereign Wealth Fund, to estimate the separate effects of income per capita and institutional quality on international capital flows. After controlling for institutional quality, GDP per capita remains the primary determinant of investment.
A Survey of Macro Damages from Non-Communicable Chronic Diseases: Another Challenge for Global Governance
Authors: Mayer-Foulkes David A.
Published: March 2011

Non-communicable chronic diseases (NCDs) are currently the largest global cause of adult mortality, one of the principal burdens of disease in developed and underdeveloped countries. Their main causes are well known, tobacco use, unhealthy diet, physical inactivity and the harmful use of alcohol. The prevalence of these risk factors is directly related to the activities of transnational corporations (TNCs). For example, just the TNC budgets dedicated to advertising risky consumption are larger than the budget of the World Health Organization.

A literature survey shows that NCDs have important long-term macroeconomic impacts, whose detailed evaluation has only just begun. The sheer burden on the working and aged population implies strong impacts on labor, saving and investment, as well as increased human capital depreciation. These will all impact long-term economic growth. It is a research priority to quantify these impacts. However, in the context of globalization, NCD is developing faster than its rigorous analysis.

Research results show that what is needed is preventive action. This requires a global institutional framework capable of controlling NCD risk factors, which can also promote health and economic growth in general. Developing legal mechanisms to slow the negative impact of the deficient nutrition transition would be a step in that direction. Global markets need to be balanced with global governance holding TNCs responsible for their impact, promoting cooperative solutions when available, and taxing them so that they carry their fair share of social weight.
Boeing and Airbus: Duopoly in Jeopardy?
Authors: Olienyk John , Carbaugh Robert J.
Published: March 2011

For decades, Boeing and Airbus have struggled for dominance in the large commercial aircraft market. In 2010 and 2011, the World Trade Organization ruled that each firm has received illegal subsidies from the governments of the United States and the European Union, which have enhanced their competitive positions. This paper considers the nature of these rulings and the future competitive environment in the global jetliner industry.
Volunteer Fire Department Perceptions of ICS and NIMS
Authors: Jensen Jessica A , Yoon D.K.
Published: March 2011

A mail survey designed to explore perceptions of the Incident Command System (ICS) and the National Incident Management System (NIMS) was sent to volunteer fire fighters and department chiefs in Spring of 2008. The data demonstrated that both ICS and NIMS were not well perceived among responding volunteer fire chiefs and volunteer fire fighters in North Dakota. Rather than indicating issues with the ICS or NIMS systems themselves, respondents’ comments revealed concerns with the systems to be rooted in their status as volunteers and their residence in rural areas.
Review of Comparative Health Systems: Global Perspectives for the 21st Century
Authors: Nicogossian Arnauld
Published: March 2011

With its well‐conceived approach, Comparative Health Systems: Global Perspectives for the 21st Century analyses the similarities and differences of healthcare systems in 17 countries.
Web Conferencing and ICTs to Enhance Undergraduate Science Teaching
Authors: Seufferheld Manfredo J. , Scagnoli Norma I.
Published: March 2011

The last decade has seen a great variety in the ways in which instructors have incorporated the World Wide Web into their traditional classroom courses; however, this combination has not always translated into changes or improvements in teaching and learning. The real challenge has proved to be not the addition of web resources to the traditional classroom, but the thoughtful combination of those resources in such a way that they enhance the educational process. This fact, added to the advancements in technology that allow for a smooth and more user-friendly integration by non-technologically savvy instructors, has resulted in successful mix of strategies that enhance the classroom learning experience. This article presents a case study that shows the changes in the design of an undergraduate science course that moved from a passive use of the Web to a more interactive and participatory use of web resources, including the incorporation of synchronous and asynchronous modes of communication and a novel use of web conferencing. The authors describe in detail the development and implementation of interactive educational technologies integrated into the course and how synchronous and asynchronous communication has enriched the teaching and learning process.
A Discussion by Any other Name: Disentangling Words and Practice in Online Conferencing
Authors: Enriquez Judith Guevarra
Published: March 2011

It is possible that the pedagogical benefits of a discussion board or any asynchronous communicative tool may not be realised as inscribed in terms like ‘collaborative learning environment’ or ‘discussion board’ due to two things: first, as instructors, we focus on what the technology can do and should do and ignore what is done when the technology is used in practice; and second, as researchers, we focus on coding messages into categories and mapping online activities into models that causes us, again, instead of seeing what is done, to try to fit our practices in situ into codes. As both instructors and researchers, we try to adhere to a constructivist view of teaching and learning. This article is about what is happening – the practice of blended/online learning and communication environment and tool (i.e. discussion board) as the technology- in-situ. It disentangles the word ‘collaborative’ from ‘technology’ and, in particular, the word ‘discussion’ from ‘board’. Our very notions of discussion or collaboration and our understanding of the so-called collaborative learning environments define the ways in which we plan for an online activity. The author argues that constructivism has become a byword influencing pedagogy, its methodologies including designing so-called learning environments in ways that hide what is really happening when we are online. The case of the discussion board is described to illustrate that the board online can be other things too.
The Impact of E-Learning on Medical Education in Russia
Authors: Trukhacheva N. , Tchernysheva S. , Krjaklina T.
Published: March 2011

New educational technologies prove to be capable of solving many problems in medical training. Students do not see e-learning as replacing traditional instructor-led training but as a complement to it, forming part of a blended-learning strategy. Innovations in e-learning technologies point toward a revolution in education, allowing learning to be individualized (adaptive learning), enhancing learners' interactions with others (collaborative learning), and transforming the role of the teacher. The integration of e-learning into medical education can catalyze the shift toward applying adult learning theory, where educators will no longer serve mainly as the distributors of content, but will become more involved as facilitators of learning and assessors of competency. Still, their use in medical schools is being hampered by certain factors. This survey is a look at how it is possible to effectively use e-learning in medical education and what steps need to be made in that direction.
The Roles of Extrinsic Factors in a Community of Inquiry Model of E-Learning
Authors: Lee Richard , Faulkner Margaret
Published: March 2011

Despite its proliferation in higher learning institutions, e-learning has been criticised as being nothing more than trivial online conversations, or a mere means of delivering class materials electronically. If e-learning is to address such criticisms and become an effective pedagogical platform, educators need to identify elements critical to the success of e-learning. A well-known framework for studying e-learning as a pedagogical platform is the community of inquiry (COI) model. In this study, the authors develop a conceptual COI model to propose that while satisfactory e-learning experience stems from the interactions among three presences – social, cognitive, and teaching – the relative influences of the presences on e-learning experience are moderated by five extrinsic factors: content richness, perceived ease of use of e-learning platform, type of curriculum, teaching orientation, and participant age. They argue that this extended and more comprehensive COI framework would help educators better understand e-learning's use as an effective pedagogical platform.