bluuebunny/crossref_metadata_2025_split huggingface dataset:
Centrality in Trade Networks and Investment in Security
Authors: Bove Vincenzo , Elia Leandro , Pelliccia Marco 
Published: December 2015

AbstractThe contemporary empirical literature on military spending has focused on institutional and conflict factors, and although has acknowledged the role of trade openness, it has not taken into account the position of a state in the trade network. Building on the concept of network centrality, we claim that the structure of trade networks affects the optimal investment in security, and that a country’s level of military spending is a function of its strategic position in the global network of a critical commodity, such as oil. Our empirical results show that network centrality constrains military spending.
Insight into catalyst deactivation mechanism and suppression techniques in thermocatalytic deoxygenation of bio-oil over zeolites
Authors: Alaba Peter Adeniyi , Sani Yahaya Muhammad , Mohammed Isah Yakub , Wan Daud Wan Mohd Ashri 
Published: December 2015

AbstractThe economic viability of the thermocatalytic upgrade of biomass-derived oxygenates is facing the challenge of low-quality products. This is because of leaching of active species, coking, and concomitant catalyst deactivation. These cumulate into the loss of catalytic activity with time on stream (TOS), which causes low degree of deoxygenation. Thus, this article reviews recent advances aimed at alleviating these setbacks to make the process viable for industrial scale-up. To understand the concept of catalyst deactivation and to offer solutions, the review scrutinized the deactivation mechanism diligently. The review also analyzes deactivation-suppression techniques such as nanocrystal zeolite cracking, hydrogen spilt-over (HSO) species, and composite catalysts (hybrid, hierarchical mesoporous zeolite, modified zeolites, and catalytic cracking deposition of silane). Interestingly, these deactivation-suppression techniques enhance catalytic properties mostly by reducing the signal strength of strong acid sites and increasing hydrothermal stability. Further, the approaches improve catalytic activity, selectivity, and TOS stability because of the lower formation of coke precursors such as polynuclear aromatics. However, despite these many advances, the need for further investigations to achieve excellent catalytic activity for industrial scale-up persists.
Dendrosomatic Sonic Hedgehog Signaling in Hippocampal Neurons Regulates Axon Elongation
Authors: Yao Pamela J. , Petralia Ronald S. , Ott Carolyn , Wang Ya-Xian , Lippincott-Schwartz Jennifer , Mattson Mark P. 
Published: December 2015

The presence of Sonic Hedgehog (Shh) and its signaling components in the neurons of the hippocampus raises a question about what role the Shh signaling pathway may play in these neurons. We show here that activation of the Shh signaling pathway stimulates axon elongation in rat hippocampal neurons. This Shh-induced effect depends on the pathway transducer Smoothened (Smo) and the transcription factor Gli1. The axon itself does not respond directly to Shh; instead, the Shh signal transduction originates from the somatodendritic region of the neurons and occurs in neurons with and without detectable primary cilia. Upon Shh stimulation, Smo localization to dendrites increases significantly. Shh pathway activation results in increased levels of profilin1 (Pfn1), an actin-binding protein. Mutations in Pfn1's actin-binding sites or reduction of Pfn1 eliminate the Shh-induced axon elongation. These findings indicate that Shh can regulate axon growth, which may be critical for development of hippocampal neurons.SIGNIFICANCE STATEMENTAlthough numerous signaling mechanisms have been identified that act directly on axons to regulate their outgrowth, it is not known whether signals transduced in dendrites may also affect axon outgrowth. We describe here a transcellular signaling pathway in embryonic hippocampal neurons in which activation of Sonic Hedgehog (Shh) receptors in dendrites stimulates axon growth. The pathway involves the dendritic-membrane-associated Shh signal transducer Smoothened (Smo) and the transcription factor Gli, which induces the expression of the gene encoding the actin-binding protein profilin 1. Our findings suggest scenarios in which stimulation of Shh in dendrites results in accelerated outgrowth of the axon, which therefore reaches its presumptive postsynaptic target cell more quickly. By this mechanism, Shh may play critical roles in the development of hippocampal neuronal circuits.
Re-Opening the Critical Window for Estrogen Therapy
Authors: Bean Linda A. , Kumar Ashok , Rani Asha , Guidi Mike , Rosario Awilda M. , Cruz Pedro E. , Golde Todd E. , Foster Thomas C. 
Published: December 2015

A decline in estradiol (E2)-mediated cognitive benefits denotes a critical window for the therapeutic effects of E2, but the mechanism for closing of the critical window is unknown. We hypothesized that upregulating the expression of estrogen receptor α (ERα) or estrogen receptor β (ERβ) in the hippocampus of aged animals would restore the therapeutic potential of E2 treatments and rejuvenate E2-induced hippocampal plasticity. Female rats (15 months) were ovariectomized, and, 14 weeks later, adeno-associated viral vectors were used to express ERα, ERβ, or green fluorescent protein (GFP) in the CA1 region of the dorsal hippocampus. Animals were subsequently treated for 5 weeks with cyclic injections of 17β-estradiol-3-benzoate (EB, 10 μg) or oil vehicle. Spatial memory was examined 48 h after EB/oil treatment. EB treatment in the GFP (GFP + EB) and ERβ (ERβ + EB) groups failed to improve episodic spatial memory relative to oil-treated animals, indicating closing of the critical window. Expression of ERβ failed to improve cognition and was associated with a modest learning impairment. Cognitive benefits were specific to animals expressing ERα that received EB treatment (ERα + EB), such that memory was improved relative to ERα + oil and GFP + EB. Similarly, ERα + EB animals exhibited enhanced NMDAR-mediated synaptic transmission compared with the ERα + oil and GFP + EB groups. This is the first demonstration that the window for E2-mediated benefits on cognition and hippocampal E2 responsiveness can be reinstated by increased expression of ERα.SIGNIFICANCE STATEMENTEstradiol is neuroprotective, promotes synaptic plasticity in the hippocampus, and protects against cognitive decline associated with aging and neurodegenerative diseases. However, animal models and clinical studies indicate a critical window for the therapeutic treatment such that the beneficial effects are lost with advanced age and/or with extended hormone deprivation. We used gene therapy to upregulate expression of the estrogen receptors ERα and ERβ and demonstrate that the window for estradiol's beneficial effects on memory and hippocampal synaptic function can be reinstated by enhancing the expression of ERα. Our findings suggest that the activity of ERα controls the therapeutic window by regulating synaptic plasticity mechanisms involved in memory.
Persistent Associative Plasticity at an Identified Synapse Underlying Classical Conditioning Becomes Labile with Short-Term Homosynaptic Activation
Authors: Hu Jiangyuan , Schacher Samuel 
Published: December 2015

Synapses express different forms of plasticity that contribute to different forms of memory, and both memory and plasticity can become labile after reactivation. We previously reported that a persistent form of nonassociative long-term facilitation (PNA-LTF) of the sensorimotor synapses inAplysia californica, a cellular analog of long-term sensitization, became labile with short-term heterosynaptic reactivation and reversed when the reactivation was followed by incubation with the protein synthesis inhibitor rapamycin. Here we examined the reciprocal impact of different forms of short-term plasticity (reactivations) on a persistent form of associative long-term facilitation (PA-LTF), a cellular analog of classical conditioning, which was expressed atAplysiasensorimotor synapses when a tetanic stimulation of the sensory neurons was paired with a brief application of serotonin on 2 consecutive days. The expression of short-term homosynaptic plasticity [post-tetanic potentiation or homosynaptic depression (HSD)], or short-term heterosynaptic plasticity [serotonin-induced facilitation or neuropeptide Phe-Met-Arg-Phe-NH2(FMRFa)-induced depression], at synapses expressing PA-LTF did not affect the maintenance of PA-LTF. The kinetics of HSD was attenuated at synapses expressing PA-LTF, which required activation of protein kinase C (PKC). Both PA-LTF and the attenuated kinetics of HSD were reversed by either a transient blockade of PKC activity or a homosynaptic, but not heterosynaptic, reactivation when paired with rapamycin. These results indicate that two different forms of persistent synaptic plasticity, PA-LTF and PNA-LTF, expressed at the same synapse become labile when reactivated by different stimuli.SIGNIFICANCE STATEMENTActivity-dependent changes in neural circuits mediate long-term memories. Some forms of long-term memories become labile and can be reversed with specific types of reactivations, but the mechanism is complex. At the cellular level, reactivations that induce a reversal of memory must evoke changes in neural circuits underlying the memory. What types of reactivations induce a labile state at neural connections that lead to reversal of different types of memory? We find that a critical neural connection inAplysia, which is modified with different stimuli that mediate different types of memory, becomes labile with different types of reactivations. These results provide insights for developing strategies in alleviating maladaptive memories accompanying anxiety disorders.
GRPR/PI3Kγ: Partners in Central Transmission of Itch
Authors: Pereira Paula J.S. , Machado Gustavo D.B. , Danesi Giuliano M. , Canevese Francesca F. , Reddy Vemuri B. , Pereira Talita C.B. , Bogo Maurício R. , Cheng Yung-Chih , Laedermann Cedric , Talbot Sébastien , Lerner Ethan A. , Campos Maria M. 
Published: December 2015

The gastrin-releasing peptide (GRP) and its receptor (GRPR) are important components of itch transmission. Upstream, but not downstream, aspects of GRPR signaling have been investigated extensively. We hypothesize that GRPR signals in part through the PI3Kγ/Akt pathway. We used pharmacological, electrophysiological, and behavioral approaches to further evaluate GRPR downstream signaling pathways. Our data show that GRP directly activates small-size capsaicin-sensitive DRG neurons, an effect that translates into transient calcium flux and membrane depolarization (∼20 mV). GRPR activation also induces Akt phosphorylation, a proxy for PI3Kγ activity, inex vivonaive mouse spinal cords and in GRPR transiently expressing HEK293 cells. The intrathecal injection of GRP led to intense scratching, an effect largely reduced by either GRPR antagonists or PI3Kγ inhibitor. Scratching behavior was also induced by the intrathecal injection of an Akt activator. In a dry skin model of itch, we show that GRPR blockade or PI3Kγ inhibition reversed the scratching behavior. Altogether, these findings are highly suggestive that GRPR is expressed by the central terminals of DRG nociceptive afferents, which transmit itch via the PI3Kγ/Akt pathway.SIGNIFICANCE STATEMENTItch is the most common symptom of the skin and is related to noncutaneous diseases. It severely impairs patients' quality of life when it becomes chronic and there is no specific or effective available therapy, mainly because itch pathophysiology is not completely elucidated. Our findings indicate that the enzyme PI3Kγ is a key central mediator of itch transmission. Therefore, we suggest PI3Kγ as an attractive target for the development of new anti-pruritic drugs. With this study, we take a step forward in our understanding of the mechanisms underlying the central transmission of itch sensation.
Muscarinic Attenuation of Mnemonic Rule Representation in Macaque Dorsolateral Prefrontal Cortex during a Pro- and Anti-Saccade Task
Authors: Major Alex J. , Vijayraghavan Susheel , Everling Stefan 
Published: December 2015

Maintenance of context is necessary for execution of appropriate responses to diverse environmental stimuli. The dorsolateral prefrontal cortex (DLPFC) plays a pivotal role in executive function, including working memory and representation of abstract rules. DLPFC activity is modulated by the ascending cholinergic system through nicotinic and muscarinic receptors. Although muscarinic receptors have been implicated in executive performance and gating of synaptic signals, their effect on local primate DLPFC neuronal activityin vivoduring cognitive tasks remains poorly understood. Here, we examined the effects of muscarinic receptor blockade on rule-related activity in the macaque prefrontal cortex by combining iontophoretic application of the general muscarinic receptor antagonist scopolamine with single-cell recordings while monkeys performed a mnemonic rule-guided saccade task. We found that scopolamine reduced overall neuronal firing rate and impaired rule discriminability of task-selective cells. Saccade and visual direction selectivity measures were also reduced by muscarinic antagonism. These results demonstrate that blockade of muscarinic receptors in DLPFC creates deficits in working memory representation of rules in primates.SIGNIFICANCE STATEMENTAcetylcholine plays a pivotal role in higher-order cognitive functions, including planning, reasoning, impulse-control, and making decisions based on contingencies or rules. Disruption of acetylcholine function is central to many psychiatric disorders manifesting cognitive impairments, including Alzheimer's disease. Although much is known about the involvement of acetylcholine and its receptors in arousal and attention, its involvement in working memory, an essential short-term memory component of cognition dependent on the integrity of prefrontal cortex, remains poorly understood. Herein, we explored the impact of suppressing acetylcholine signaling on neurons encoding memorized rules while macaque monkeys made responses based on those rules. Our findings provide insights into the neural mechanisms by which a disruption in acetylcholine function impairs working memory in the prefrontal cortex.
Ectopic Expression of α6 and δ GABAAReceptor Subunits in Hilar Somatostatin Neurons Increases Tonic Inhibition and Alters Network Activity in the Dentate Gyrus
Authors: Tong Xiaoping , Peng Zechun , Zhang Nianhui , Cetina Yliana , Huang Christine S. , Wallner Martin , Otis Thomas S. , Houser Carolyn R. 
Published: December 2015

The role of GABAAreceptor (GABAAR)-mediated tonic inhibition in interneurons remains unclear and may vary among subgroups. Somatostatin (SOM) interneurons in the hilus of the dentate gyrus show negligible expression of nonsynaptic GABAAR subunits and very low tonic inhibition. To determine the effects of ectopic expression of tonic GABAAR subtypes in these neurons, Cre-dependent viral vectors were used to express GFP-tagged GABAAR subunits (α6 and δ) selectively in hilar SOM neurons in SOM-Cre mice. In single-transfected animals, immunohistochemistry demonstrated strong expression of either the α6 or δ subunit; in cotransfected animals, both subunits were consistently expressed in the same neurons. Electrophysiology revealed a robust increase of tonic current, with progressively larger increases following transfection of δ, α6, and α6/δ subunits, respectively, indicating formation of functional receptors in all conditions and likely coassembly of the subunits in the same receptor following cotransfection. Anin vitromodel of repetitive bursting was used to determine the effects of increased tonic inhibition in hilar SOM interneurons on circuit activity in the dentate gyrus. Upon cotransfection, the frequency of GABAAR-mediated bursting in granule cells was reduced, consistent with a reduction in synchronous firing among hilar SOM interneurons. Moreover,in vivostudies of Fos expression demonstrated reduced activation of α6/δ-cotransfected neurons following acute seizure induction by pentylenetetrazole. The findings demonstrate that increasing tonic inhibition in hilar SOM interneurons can alter dentate gyrus circuit activity during strong stimulation and suggest that tonic inhibition of interneurons could play a role in regulating excessive synchrony within the network.SIGNIFICANCE STATEMENTIn contrast to many hippocampal interneurons, somatostatin (SOM) neurons in the hilus of the dentate gyrus have very low levels of nonsynaptic GABAARs and exhibit very little tonic inhibition. In an effort to increase tonic inhibition selectively in these interneurons, we used Cre-dependent viral vectors in SOM-Cre mice to achieve interneuron-specific expression of the nonsynaptic GABAAR subunits (α6 and δ)in vivo. We show, for the first time, that such recombinant GFP-tagged GABAAR subunits are expressed robustly, assemble to form functional receptors, substantially increase tonic inhibition in SOM interneurons, and alter circuit activity within the dentate gyrus.
Choix et strategies d’alliance : chroniques presque contrefactuelles des réseaux parentaux dans le patriciat vénitien, XVIII siècle
Authors: Munno Cristina , Derosas Renzo 
Published: December 2015

En este trabajo emplearemos un instrumento metodológico que nos ayudará a entender cómo la elección y el establecimiento de alianzas podría estar determinado por condicionantes políticos y estratégicos. Centrándonos en la República de Venecia durante el siglo XVIII, estudiaremos las características, las actitudes, los impulsos y los intereses que se esconden tras las alianzas establecidas por la aristocracia; unas marcadas por un claro componente político y otras por el deseo de adquirirlo. Tomando como referencia a sus matrimonios, exploraremos el significado de sus alianzas utilizando las herramientas propias del Social Network Analysis. Sus opciones matrimoniales y las redes que se derivan de ellas se compararán con las que nacerían de otras posibles opciones matrimoniales. El instrumento de análisis que proponemos se centra sobre la actividad desplegada por la familia Manin, gracias a la cual podremos comparar los beneficios de las hipotéticas relaciones que establecería con estas o aquellas familias. Esta investigación tiene por objeto ayudarnos a comprender la complejidad de las relaciones sociales y familiares de la aristocracia veneciana, y también, advertir de la posibilidad de ofrecer nuevos enfoques a la historia social y política.http://dx.doi.org/10.15304/ohm.24.2822
AVANCEMOS: Effects of school dropout in the Home of Beneficiaries
Authors: Muñoz-Alvarado José Alfonso 
Published: December 2015

The following paper shows the difference between the variables that explain school dropout in households in which at least one person is an AVANCEMOS beneficiary and in households where no member is. Furthermore, it seeks to demonstrate whether there is any effect on the program AVANCEMOS on siblings of a beneficiary in their decision to leave the educational system. Using The National Household Survey 2013 from INEC and through descriptive statistics and logistic models, we obtain results in which some variables that influence dropout such as area, quality of housing, basic services and gender have no influence in the same way households having AVANCEMOS or not. Meanwhile, age is always important for students when deciding to withdraw from the educational system regardless of the conditions of their home. Moreover, being 18 years old is a critical age since it represents a breaking point in the decision of the student to continue studying or not. If they come from an AVANCEMOS home, AVANCEMOS does not have any effect on siblings of beneficiaries of the program, but account to a higher proportion of students who leave school to go to work, 59.28%; against those who come from a home that does not participate in the program, which corresponds to a 48.35% of this population.
Rates of Educational Attainment in the Afro-descendant, Indigenous and Mestizo Populations: Review of Some Exclusion Factors
Authors: Gaete-Astica Marcelo 
Published: December 2015

This article is the result of the research Rates of Educational Attainment among the Afro-descendant, Indigenous and Mestizo Populations and the Review of Some Exclusion and Inclusion Factors (Gaete, 2014). This article studies the 10th National Population Census and applies some quantitative measures in an attempt to establish the educational attainment of individuals of aboriginal and Afro-American descent, in contrast to that of the mestizo population (uncritically labeled as “white”). Additionally, educational exclusion factors are explored such as geographical location of the populations of interest and insertion of under-aged population in the job market. Since this study has an exploratory scope, it is intended to give practical and conceptual inputs to delve into the social and educational exclusion theme. Statistical analysis conducted offers a view of the fact that ethnic and cultural identity, as well as geographic location (at a provincial scale) do not seem to be determining factors of educational and social exclusion. On the contrary, explanations must be sought in the circular character of poverty that determines low educational attainment, which in turn determines access to low-level jobs. In this sense, this study suggests that early insertion in the job market is a key exclusionary factor.
Co-teaching in information literacy during work placements: the librarian’s role
Authors: Kolstad Anett Kristin 
Published: December 2015

Introduction: This article presents findings from a development project designed to improve Information Literacy (IL) education by linking it to nursing students’ application of evidence-based practice during work placements. The Learning Centre at Oslo University College in Norway aimed to find out, what interactions and conditions influenced the librarian’s role in the context of interdisciplinary supervision of nursing students’ assignments and the development of a common supervision culture. Research Design: The librarian involved in the initiative had a dual role as both researcher and practitioner. Besides direct experiences from being a participant in the project, the empirical material consists of observation notes, meeting notes, presentations, guideline in IL, e-mails, an interview, 285 comments from students, nurse educators, nurse supervisors and librarians, through blog and the Wiki Learning Management System (LMS). The evidence on which this article is based involved analysis of both oral and written communication, framed in practice-oriented approaches. Findings: The conditions influencing the changing position of the librarian from an ‘outsider’ to becoming a member of the community of practice with common structures for the collaboration and supervision included meetings, a blog and a Wiki. Multidisciplinary, complementary skills in the supervision teams provided improved quality of supervision and led to a new joint supervision community. Conclusion: Together with the nurse educators and the nurse supervisors, the librarian was able to be a partner and a catalyst of IL workplace learning. The LMS was a decisive tool in the process. However, to be successful, this changed role for the librarian may require further pedagogical training and expertise in the development of interdisciplinary educational supervision.