bluuebunny/crossref_metadata_2025 huggingface dataset:
The Timing of Dopamine- and Noradrenaline-Mediated Transmission Reflects Underlying Differences in the Extent of Spillover and Pooling
Authors: Courtney Nicholas A. , Ford Christopher P.
Published: May 2014

Metabotropic transmission typically occurs through the spillover activation of extrasynaptic receptors. This study examined the mechanisms underlying somatodendritic dopamine and noradrenaline transmission and found that the extent of spillover and pooling varied dramatically between these two transmitters. In the mouse ventral tegmental area, the time course of D2-receptor-mediated IPSCs (D2-IPSCs) was consistent between cells and was unaffected by altering stimulation intensity, probability of release, or the extent of diffusion. Blocking dopamine reuptake with cocaine extended the time course of D2-IPSCs and suggested that transporters strongly limited spillover. As a result, individual release sites contributed independently to the duration of D2-IPSCs. In contrast, increasing the release of noradrenaline in the rat locus ceruleus prolonged the duration of α2-receptor-mediated IPSCs even when reuptake was intact. Spillover and subsequent pooling of noradrenaline activated distal α2-receptors, which prolonged the duration of α2-IPSCs when multiple release sites were activated synchronously. By using the rapid application of agonists onto large macropatches, we determined the concentration profile of agonists underlying the two IPSCs. Incorporating the results into a model simulating extracellular diffusion predicted that the functional range of noradrenaline diffusion was nearly fivefold greater in the locus ceruleus than dopamine in the midbrain. This study demonstrates that catecholamine synapses differentially regulate the extent of spillover and pooling to control the timing of local inhibition and suggests diversity in the roles of uptake and diffusion in governing metabotropic transmission.
Induced Alpha Rhythms Track the Content and Quality of Visual Working Memory Representations with High Temporal Precision
Authors: Anderson David E. , Serences John T. , Vogel Edward K. , Awh Edward
Published: May 2014

Past work has suggested that neuronal oscillations coordinate the cellular assemblies that represent items in working memory (WM). In line with this hypothesis, we show that the spatial distribution of power in the alpha frequency band (8–12 Hz) can be used to decode the content and quality of the representations stored in visual WM. We acquired EEG data during an orientation WM task, and used a forward encoding model of orientation selectivity to reconstruct orientation-specific response profiles (termed channel tuning functions, or CTFs) that tracked the orientation of the memorandum during both encoding and delay periods of the trial. Critically, these EEG-based CTFs were robust predictors of both between- and within-subject differences in mnemonic precision, showing that EEG-based CTFs provide a sensitive measure of the quality of sensory population codes. Experiments 2 and 3 established that these EEG-based CTFs are contingent on the voluntary storage goals of the observer. When observers were given a postsample cue to store or drop the memorandum, the resulting CTF was sustained in the “store” condition and rapidly eliminated following the “drop” cue. When observers were instructed to store one of two simultaneously presented stimuli, only the stored item was represented in a sustained fashion throughout the delay period. These findings suggest that the oscillatory activity in the alpha frequency band plays a central role in the active storage of information in visual WM, and demonstrate a powerful approach for tracking the precision of on-line memories with high temporal resolution.
Nonlinear Spatial Integration in the Receptive Field Surround of Retinal Ganglion Cells
Authors: Takeshita Daisuke , Gollisch Tim
Published: May 2014

Throughout different sensory systems, individual neurons integrate incoming signals over their receptive fields. The characteristics of this signal integration are crucial determinants for the neurons' functions. For ganglion cells in the vertebrate retina, receptive fields are characterized by the well-known center-surround structure and, although several studies have addressed spatial integration in the receptive field center, little is known about how visual signals are integrated in the surround. Therefore, we set out here to characterize signal integration and to identify relevant nonlinearities in the receptive field surround of ganglion cells in the isolated salamander retina by recording spiking activity with extracellular electrodes under visual stimulation of the center and surround. To quantify nonlinearities of spatial integration independently of subsequent nonlinearities of spike generation, we applied the technique of iso-response measurements as follows: using closed-loop experiments, we searched for different stimulus patterns in the surround that all reduced the center-evoked spiking activity by the same amount. The identified iso-response stimuli revealed strongly nonlinear spatial integration in the receptive field surrounds of all recorded cells. Furthermore, cell types that had been shown previously to have different nonlinearities in receptive field centers showed similar surround nonlinearities but differed systematically in the adaptive characteristics of the surround. Finally, we found that there is an optimal spatial scale of surround suppression; suppression was most effective when surround stimulation was organized into subregions of several hundred micrometers in diameter, indicating that the surround is composed of subunits that have strong center-surround organization themselves.
Associative Hebbian Synaptic Plasticity in Primate Visual Cortex
Authors: Huang Shiyong , Rozas Carlos , Treviño Mario , Contreras Jessica , Yang Sunggu , Song Lihua , Yoshioka Takashi , Lee Hey-Kyoung , Kirkwood Alfredo
Published: May 2014

In primates, the functional connectivity of adult primary visual cortex is susceptible to be modified by sensory training during perceptual learning. It is widely held that this type of neural plasticity might involve mechanisms like long-term potentiation (LTP) and long-term depression (LTD). NMDAR-dependent forms of LTP and LTD are particularly attractive because in rodents they can be induced in a Hebbian manner by near coincidental presynaptic and postsynaptic firing, in a paradigm termed spike timing-dependent plasticity (STDP). These fundamental properties of LTP and LTD, Hebbian induction and NMDAR dependence, have not been examined in primate cortex. Here we demonstrate these properties in the primary visual cortex of the rhesus macaque (Macaca mulatta), and also show that, like in rodents, STDP is gated by neuromodulators. These findings indicate that the cellular principles governing cortical plasticity are conserved across mammalian species, further validating the use of rodents as a model system.
Simultaneous Recordings from the Primary Visual Cortex and Lateral Geniculate Nucleus Reveal Rhythmic Interactions and a Cortical Source for Gamma-Band Oscillations
Authors: Bastos Andre M. , Briggs Farran , Alitto Henry J. , Mangun George R. , Usrey W. Martin
Published: May 2014

Oscillatory synchronization of neuronal activity has been proposed as a mechanism to modulate effective connectivity between interacting neuronal populations. In the visual system, oscillations in the gamma-frequency range (30–100 Hz) are thought to subserve corticocortical communication. To test whether a similar mechanism might influence subcortical-cortical communication, we recorded local field potential activity from retinotopically aligned regions in the lateral geniculate nucleus (LGN) and primary visual cortex (V1) of alert macaque monkeys viewing stimuli known to produce strong cortical gamma-band oscillations. As predicted, we found robust gamma-band power in V1. In contrast, visual stimulation did not evoke gamma-band activity in the LGN. Interestingly, an analysis of oscillatory phase synchronization of LGN and V1 activity identified synchronization in the alpha (8–14 Hz) and beta (15–30 Hz) frequency bands. Further analysis of directed connectivity revealed that alpha-band interactions mediated corticogeniculate feedback processing, whereas beta-band interactions mediated geniculocortical feedforward processing. These results demonstrate that although the LGN and V1 display functional interactions in the lower frequency bands, gamma-band activity in the alert monkey is largely an emergent property of cortex.
Value Signals in the Prefrontal Cortex Predict Individual Preferences across Reward Categories
Authors: Gross Jörg , Woelbert Eva , Zimmermann Jan , Okamoto-Barth Sanae , Riedl Arno , Goebel Rainer
Published: May 2014

Humans can choose between fundamentally different options, such as watching a movie or going out for dinner. According to the utility concept, put forward by utilitarian philosophers and widely used in economics, this may be accomplished by mapping the value of different options onto a common scale, independent of specific option characteristics (Fehr and Rangel, 2011; Levy and Glimcher, 2012). If this is the case, value-related activity patterns in the brain should allow predictions of individual preferences across fundamentally different reward categories. We analyze fMRI data of the prefrontal cortex while subjects imagine the pleasure they would derive from items belonging to two distinct reward categories: engaging activities (like going out for drinks, daydreaming, or doing sports) and snack foods. Support vector machines trained on brain patterns related to one category reliably predict individual preferences of the other category and vice versa. Further, we predict preferences across participants. These findings demonstrate that prefrontal cortex value signals follow a common scale representation of value that is even comparable across individuals and could, in principle, be used to predict choice.
Synaptic Modifications in the Medial Prefrontal Cortex in Susceptibility and Resilience to Stress
Authors: Wang Minghui , Perova Zinaida , Arenkiel Benjamin R. , Li Bo
Published: May 2014

When facing stress, most individuals are resilient whereas others are prone to developing mood disorders. The brain mechanisms underlying such divergent behavioral responses remain unclear. Here we used the learned helplessness procedure in mice to examine the role of the medial prefrontal cortex (mPFC), a brain region highly implicated in both clinical and animal models of depression, in adaptive and maladaptive behavioral responses to stress. We found that uncontrollable and inescapable stress induced behavioral state-dependent changes in the excitatory synapses onto a subset of mPFC neurons: those that were activated during behavioral responses as indicated by their expression of the activity reporter c-Fos. Whereas synaptic potentiation was linked to learned helplessness, a depression-like behavior, synaptic weakening, was associated with resilience to stress. Notably, enhancing the activity of mPFC neurons using a chemical–genetic method was sufficient to convert the resilient behavior into helplessness. Our results provide direct evidence that mPFC dysfunction is linked to maladaptive behavioral responses to stress, and suggest that enhanced excitatory synaptic drive onto mPFC neurons may underlie the previously reported hyperactivity of this brain region in depression.
Cdk5-Dependent Mst3 Phosphorylation and Activity Regulate Neuronal Migration through RhoA Inhibition
Authors: Tang Jing , Ip Jacque P.K. , Ye Tao , Ng Yu-Pong , Yung Wing-Ho , Wu Zhenguo , Fang Weiqun , Fu Amy K.Y. , Ip Nancy Y.
Published: May 2014

The radial migration of newborn neurons is critical for the lamination of the cerebral cortex. Proper neuronal migration requires precise and rapid reorganization of the actin and microtubule cytoskeleton. However, the underlying signaling mechanisms controlling cytoskeletal reorganization are not well understood. Here, we show that Mst3, a serine/threonine kinase highly expressed in the developing mouse brain, is essential for radial neuronal migration and final neuronal positioning in the developing mouse neocortex. Mst3 silencing byin uteroelectroporation perturbed the multipolar-to-bipolar transition of migrating neurons and significantly retards radial migration. Although the kinase activity of Mst3 is essential for its functions in neuronal morphogenesis and migration, it is regulated via its phosphorylation at Ser79 by a serine/threonine kinase, cyclin-dependent kinase 5 (Cdk5). Our results show that Mst3 regulates neuronal migration through modulating the activity of RhoA, a Rho-GTPase critical for actin cytoskeletal reorganization. Mst3 phosphorylates RhoA at Ser26, thereby negatively regulating the GTPase activity of RhoA. Importantly, RhoA knockdown successfully rescues neuronal migration defect in Mst3-knockdown cortices. Our findings collectively suggest that Cdk5–Mst3 signaling regulates neuronal migration via RhoA-dependent actin dynamics.
Culinary Pataphysics
Authors: Landis Kevin
Published: May 2014

The movement that is known as molecular gastronomy has received much attention over the past decade, both as a compelling artistic breach of “ordinary cuisine” and for its privileging the scientific advancement of food preparation. The great chefs of this movement are received as auteurs of the meals that they create; not simply chefs, but avant-garde performers. This article proposes that many of the facets of modern haute cuisine have parallels in the historical avant-garde. Through a theatrical lens, Culinary Pataphysics explores some of the history of food’s artistry and draws parallels between drama and cuisine and both disciplines’ use of simulation and disruption. With Alfred Jarry’s remarkable play Ubu Roi as a starting point, three famous restaurants are assessed as contemporary exemplars of an artistic movement that has long been pronounced dead.
RARRES3 suppresses breast cancer lung metastasis by regulating adhesion and differentiation
Authors: Morales Mònica , Arenas Enrique J , Urosevic Jelena , Guiu Marc , Fernández Esther , Planet Evarist , Fenwick Robert Bryn , Fernández‐Ruiz Sonia , Salvatella Xavier , Reverter David , Carracedo Arkaitz , Massagué Joan , Gomis Roger R
Published: May 2014

In estrogen receptor‐negative breast cancer patients, metastatic relapse usually occurs in the lung and is responsible for the fatal outcome of the disease. Thus, a better understanding of the biology of metastasis is needed. In particular, biomarkers to identify patients that are at risk of lung metastasis could open the avenue for new therapeutic opportunities. Here we characterize the biological activity of RARRES3, a new metastasis suppressor gene whose reduced expression in the primary breast tumors identifies a subgroup of patients more likely to develop lung metastasis. We show that RARRES3 downregulation engages metastasis‐initiating capabilities by facilitating adhesion of the tumor cells to the lung parenchyma. In addition, impaired tumor cell differentiation due to the loss of RARRES3 phospholipase A1/A2 activity also contributes to lung metastasis. Our results establish RARRES3 downregulation as a potential biomarker to identify patients at high risk of lung metastasis who might benefit from a differentiation treatment in the adjuvant programme.
Physiological responses to psychological stress: importance of adiposity in men aged 50–70 years
Authors: Jayasinghe S U , Torres S J , Nowson C A , Tilbrook A J , Turner A I
Published: May 2014

We tested the hypothesis that overweight/obese men aged 50–70 years will have a greater salivary cortisol, salivary alpha amylase and heart rate (HR) responses to psychological stress compared with age matched lean men. Lean (BMI=20–25 kg/m2; n=19) and overweight/obese (BMI=27–35 kg/m2; n=17) men (50–70 years) were subjected to a well-characterised psychological stress (Trier Social Stress Test, TSST) at 1500 h. Concentrations of cortisol and alpha amylase were measured in saliva samples collected every 7–15 min from 1400 to 1700 h. HR was recorded using electrocardiogram. Body weight, BMI, percentage body fat, resting systolic and diastolic blood pressure and mean arterial pressure were significantly higher (P<0.05) in overweight/obese men compared with lean men. Both groups responded to the TSST with a substantial elevation in salivary cortisol (372%), salivary alpha amylase (123%) and HR (22%). These responses did not differ significantly between the groups (time×treatment interaction for salivary cortisol, salivary alpha amylase and HR; P=0.187, P=0.288, P=0.550, respectively). There were no significant differences between the groups for pretreatment values, peak height, difference between pretreatment values and peak height (reactivity) or area under the curve for salivary cortisol, salivary alpha amylase or HR (P>0.05 for all). The results showed that, for men with a moderate level of overweight/obesity who were otherwise healthy, the response of salivary cortisol, salivary alpha amylase and HR to acute psychological stress was not impaired.
Stimulated thyroglobulin level at ablation in differentiated thyroid cancer: the impact of treatment preparation modalities and tumor burden
Authors: Ciappuccini Renaud , Hardouin Juliette , Heutte Natacha , Vaur Dominique , Quak Elske , Rame Jean-Pierre , Blanchard David , de Raucourt Dominique , Bardet Stéphane
Published: May 2014

Objective

In patients with differentiated thyroid cancer (DTC), the stimulated serum thyroglobulin (Tg) level at radioiodine ablation is a known predictive factor of persistent disease. This prognostic value is based on data obtained after thyroid hormone withdrawal (THW), but little is known about this prognostic value after recombinant human TSH (rhTSH) stimulation and about the relationship between the stimulated Tg level and the burden of persistent tumor. We aimed to assess the impact of both radioiodine preparation modalities and persistent tumor burden on stimulated Tg levels.

Design and methods

The stimulated Tg level was measured at radioablation in 308 consecutive DTC patients without serum Tg antibodies. Of these, 123 (40%) were prepared with rhTSH and 185 with THW. Post-ablation scintigraphy included total-body scan and neck and thorax single photon emission computed tomography with computed tomography (SPECT–CT). During a mean follow-up of 43 months, persistent/recurrent disease (PRD) was found in 56 patients (18%). PRD was considered structural in the presence of lesions >1 cm and nonstructural otherwise.

Results

Nonstructural PRD was more frequent in the rhTSH group than in the THW group (64 vs 26%,P=0.01). Stimulated Tg levels were lower after rhTSH than after THW in patients with (13.5 vs 99.5 ng/ml,P<0.01) and without (1.2 vs 3.2 ng/ml,P<0.001) PRD. Also, Tg levels were lower in nonstructural disease than in structural disease in both rhTSH (3.8 vs 127.0 ng/ml,P<0.01) and THW (13.0 vs 143.5 ng/ml,P<0.0001) patients. The best Tg cutoff to predict PRD was 2.8 in rhTSH and 28 ng/ml in THW patients.

Conclusion

Both radioiodine preparation modalities and the burden of persistent tumor affect the stimulated Tg level at ablation.
GH receptor isoforms and skeletal fragility in acromegaly
Authors: Mormando Marilda , Nasto Luigi A , Bianchi Antonio , Mazziotti Gherardo , Giampietro Antonella , Pola Enrico , Pontecorvi Alfredo , Giustina Andrea , De Marinis Laura
Published: May 2014

Objective

Acromegaly is associated with an increased prevalence of vertebral fractures (VFs) in close relationship with GH hypersecretion. Two isoforms of the GH receptor (GHR) have been identified; the two isoforms differ or not by the expression of the protein fragment encoded by exon 3 of the GHR gene. Deletion of the exon 3 may influence the functional properties of the GHR and affect fracture risk in acromegalic patients.

Design

A cross-sectional study was designed to investigate the association between the d3-GHR isoform and the prevalence of VFs in patients with acromegaly.

Methods

In this study, 109 acromegalic patients were included (M/F, 48/61): 73 with controlled/cured acromegaly and 36 with active disease. GHR genotype was assessed in each patient. All patients were evaluated for VFs and bone mineral density at lumbar spine and hip. Serum IGF1 levels and bone metabolism markers were measured. A multivariate analysis was performed to establish risk factors for VFs in our population.

Results

d3-GHR carriers showed an increased prevalence of VFs when compared with patients expressing full-length GHR (35/55 vs 12/54; P<0.001). The association between GHR deletion and VFs was demonstrated both in patients with active disease and in those with controlled/cured disease. Out of 35 patients who were prospectively evaluated, 13 (37.1%) developed incident VFs. The incidence of VFs was significantly higher in patients for whom the GHR gene has been deleted when compared with those harboring the fl gene (P=0.04). In multivariate analysis, male sex (odds ratio (OR), 3.250; P=0.041), IGF1 levels (OR, 1.183; P=0.031), length of active diseases (OR, 1.038; P=0.001), and d3-GHR genotype (OR, 3.060; P=0.015) were all confirmed as risk factors of VFs in our population.

Conclusions

This study suggests for the first time that exon 3 deletion of GHR may predispose patients with active and controlled acromegaly to a higher risk of VFs.
MOLECULAR EVOLUTION OF GPCRS: Secretin/secretin receptors
Authors: Tam Janice K V , Lee Leo T O , Jin Jun , Chow Billy K C
Published: May 2014

In mammals, secretin is a 27-amino acid peptide that was first studied in 1902 by Bayliss and Starling from the extracts of the jejunal mucosa for its ability to stimulate pancreatic secretion. To date, secretin has only been identified in tetrapods, with the earliest diverged secretin found in frogs. Despite being the first hormone discovered, secretin's evolutionary origin remains enigmatic, it shows moderate sequence identity in nonmammalian tetrapods but is highly conserved in mammals. Current hypotheses suggest that although secretin has already emerged before the divergence of osteichthyans, it was lost in fish and retained only in land vertebrates. Nevertheless, the cognate receptor of secretin has been identified in both actinopterygian fish (zebrafish) and sarcopterygian fish (lungfish). However, the zebrafish secretin receptor was shown to be nonbioactive. Based on the present information that the earliest diverged bioactive secretin receptor was found in lungfish, and its ability to interact with both vasoactive intestinal peptide and pituitary adenylate cyclase-activating polypeptide potently suggested that secretin receptor was descended from a VPAC-like receptor gene before the Actinopterygii–Sarcopterygii split in the vertebrate lineage. Hence, secretin and secretin receptor have gone through independent evolutionary trajectories despite their concurrent emergence post-2R. A functional secretin–secretin receptor axis has probably emerged in the amphibians. Although the pleiotropic actions of secretin are well documented in the literature, only limited information of its physiological functions in nonmammalian tetrapods have been reported. To decipher the structural and functional divergence of secretin and secretin receptor, functional characterization of the ligand–receptor pair in nonmammals would be the next perspective for investigation.
Metabolic profiling in diabetes
Authors: Suhre Karsten
Published: May 2014

Metabolic profiling, or metabolomics, has developed into a mature science in recent years. It has major applications in the study of metabolic disorders. This review addresses issues relevant to the choice of the metabolomics platform, study design and data analysis in diabetes research, and presents recent advances using metabolomics in the identification of markers for altered metabolic pathways, biomarker discovery, challenge studies, metabolic markers of drug efficacy and off-target effects. The role of genetic variance and intermediate metabolic phenotypes and its relevance to diabetes research is also addressed.
Violence and growth in Colombia: A review of the quantitative literature
Authors: Riascos Alvaro J. , Vargas Juan F.
Published: May 2014

This is a critical review of the empirical literature on the relationship between violence and economic growth in Colombia, an interesting case study for social scientists studying violence, conflict, crime, and development. We argue that despite the rapid development of this literature and the increasing use of new quantitative techniques, there is still much room for research. After assessing the contribution of the most influential papers on the subject, we suggest directions for future research.
A theoretical approach to the demand and supply for peacekeeping
Authors: Bove Vincenzo
Published: May 2014

The post-cold war period is characterized by peace operations and negotiations, with increased size, number, and intensity of external interventions, particularly those sponsored by multilateral organizations. This article examines some factors that influence the demand for peacekeeping missions, i.e., conflict situations that invite third-party interventions, as well as the supply of peacekeeping, the ability and desire of states to intervene elsewhere through peacekeeping missions. On the demand side, a framework is developed that synthesizes the main obstacles to peacekeeping intervention, in particular the role of overconfidence, and explains how interpersonal preferences, such as the desire for vengeance, contribute to conflict escalation. On the supply side, the article explains some of the conditions determining countries' contribution to peace missions.
Determinants of military expenditure in Zimbabwe
Authors: Tambudzai Zachary
Published: May 2014

While many articles have been written on the determinants of military expenditure in developing countries, few have attempted to use a qualitative approach to investigate the underlying motives for military expenditure. This article uses data drawn from interviews with key informants and documentary sources to study the determinants of military expenditure in Zimbabwe. Findings suggest that Zimbabwe's military expenditure since 1980 has been influenced more by internal political dynamics than by economic factors. The most significant factors include regime security, elite corruption and rent-seeking, liberation war ideology hangover, and fear.
Economic, political, and social determinants of peace
Authors: Huang Sterling , Throsby David
Published: May 2014

Although quite a lot is known about the economics of war and conflict, rather less is known about the economics of peace. In this article we address the question: What are the major factors likely to lead countries toward peacefulness? We categorize these factors in three groups: economic, political, and socio-demographic, and test a set of hypotheses as to their influence using data for 2007 and 2008 covering more than 100 countries. Our results show that all three groups of factors play some part in contributing toward peacefulness in a country. In particular, among the economic factors we find that the most important influence is exerted by the openness of the economy. Political factors also emerge as significant, indicating that a properly constituted well-functioning democratic system of governance free of political corruption is an important requirement for the achievement of a peaceful society.
Natural resources and military expenditure: The case of Algeria
Authors: Perlo-Freeman Sam , Brauner Jennifer
Published: May 2014

With world military expenditure rising rapidly since 2000, one of the possible drivers that has drawn less attention has been the role of natural resource revenues, especially oil. Countries as diverse as Angola, Azerbaijan, Chad, Iraq, Kazakhstan, Nigeria, and Timor-Leste have seen huge rises in military expenditure on the back of rapidly increasing oil revenues. Natural resource extraction can generate conflict and create an imperative to protect resource infrastructure from internal or external threats. At the same time it provides a ready source of government revenue, and in particular foreign currency. The lack of transparency often associated with such revenues may facilitate off-budget spending or large, and possibly corrupt, arms purchases. Up to now, most econometric research has not considered the role of resource revenues as a determinant of military expenditure. We provide a preliminary analysis for the case of Algeria, estimating military expenditure as a function of oil revenues and other economic and security factors from 1975 to 2008. We find some evidence that oil revenues have had a statistically significant positive effect on Algerian military expenditure.
Terrorism, war, and global air traffic
Authors: Brauer Jurgen , Dunne J. Paul
Published: May 2014

It is thought that one of the affected industries of the 9/11 terror event was the global airline industry through the attack's effects on global air traffic demand for international, scheduled flights. Using data from the International Civil Aviation Organization, this article considers whether this was indeed the case. The study applies panel data analysis, focusing on the 20 largest airline companies. We find that when one takes account of potential confounding factors such as the general state of the economy, global air traffic was not greatly affected by the general level of terrorist attacks worldwide, and that it takes a truly exceptional event such as 9/11 to find a measurable impact on air traffic demand. Even then, the measured effect for the industry as a whole is small in magnitude. The reason for this finding appears to be that the demand for international scheduled air flights is rather heterogeneous across airlines. Aggregating across the whole of the global industry is not in all instances warranted.
Analyzing the costs of military engagement
Authors: De Groot Olaf J.
Published: May 2014

Analyzing governments' expenditure when it comes to military engagement is a challenging task. As governments are neither transparent nor eager to come forward with the necessary information, researchers make a lot of assumptions that require extensive justification. This article details a range of relevant cost channels and describes the difficulties in estimating their respective sizes. But when worked-up in a careful and deliberate way, it is possible to obtain reasonable estimates of the budgetary effects of military engagements. Following the outlined methodology creates an opportunity to improve openness, which will benefit researchers, policymakers, and the public at large.
Does development assistance reduce violence? Evidence from Afghanistan
Authors: Chou Tiffany
Published: May 2014

Current military doctrine emphasizes the importance of development spending in reducing insurgent violence. Using data from three distinct development programs, the Afghan National Solidarity Program, USAID's Local Governance and Community Development Program, and the U.S. military's Commander's Emergency Response Program (CERP), combined with military records of insurgent-initiated events, this article explores whether development aid in Afghanistan is violence-reducing. I find that overall spending has no clear effect on rebel attacks. Moreover, the type of development program most effective at reducing violence in Iraq - small CERP projects - does not appear to do so in Afghanistan. Possible reasons include troop strength, conditionality of aid, effectiveness of aid in producing benign outcomes, and measurement issues.
Demand and supply of commercial firearms in the United States
Authors: Brauer Jurgen
Published: May 2014

The article establishes methods by which to estimate demand and supply in the commercial firearms market in the United States. For the first time, this includes the number of used firearms resold via federally licensed retailers. For 2010, for example, total unit sales are estimated at 9.8 million pistols, revolvers, rifles, and shotguns, about 1.5 million of which were used weapons. The total number of military and nonmilitary firearms that entered commerce between 1986 and 2010 is estimated at about 150 million units. Allowing for pre-1986 production and imports, this lends credence to the notion that the total stock of firearms in the U.S. averages about one firearm per person. The article further shows rising firearms imports. In 2010, these amounted to about one-third of the total market. In addition to imports, foreign brands also produce at U.S. locations and, in 2010, captured well over 20 percent of the U.S. commercial pistol market.
Military expenditure and economic growth: A survey
Authors: Dunne J. Paul , Tian Nan
Published: May 2014

Until recently, a long-standing, impressively large, and growing literature on the effects of military expenditure on economic growth appeared to have failed to result in a scholarly consensus. But the availability of 20 more years of data since the thawing of the cold war has helped researchers to make progress in identifying any relation of military expenditure with economic factors. The literature is complex and difficult to summarize, with studies differing in their theoretical approach, in the empirical methods used, in the coverage of countries and time periods employed, and in their quality and statistical significance. This article extends and updates an earlier survey, now covering almost 170 studies. It finds that more recent studies provide stronger evidence of a negative effect of military expenditure on economic growth.
Envy in the process of development: Implications for Social Relations and Conflict
Authors: Gershman Boris
Published: May 2014

This article examines envy as an important cultural link between inequality, institutions, development, and conflict. It argues that envy can be either a source of strife and stagnation or an engine for peaceful competition and growth. The fundamental conditions that activate the constructive side of envy and shut down its destructive side are access to productive investment opportunities, equality, security of property rights, and mild social comparisons. The dominant role of envy in society gives rise to a set of related cultural norms and beliefs that affect economic performance and social relations. While constructive envy is manifested in emulation or even envy-provocation -standard features of a consumer society- destructive envy produces a fear-of-envy culture that hampers economic incentives and creates an environment of suspicion and conflict.
The political economy of peacebuilding: The case of women's cooperatives in Nepal
Authors: Ramnarain Smita
Published: May 2014

Critiques of liberal, top-down approaches to peacebuilding have motivated a discussion of alternative, locally-led, and community-based approaches to achieving and maintaining sustainable peace. This article uses a case study of women's savings and credit cooperatives in post-violence Nepal to examine the ways in which grassroots-based, locally-led peace initiatives can counter top-down approaches. The article presents ethnographic evidence from fieldwork in Nepal on how cooperatives expand through their everyday activities the definition of peace to include not only the absence of violence (negative peace) but transformatory goals such as social justice (positive peace). By focusing on ongoing root causes of structural violence, cooperatives problematize the postconflict period where pre-war normalcy is presumed to have returned. They emphasize local agency and ownership over formal peace processes. The findings suggest ongoing struggles that cooperatives face due to their existence within larger, liberal paradigms of international postconflict aid and reconstruction assistance. Their uneasy relationship with liberal economic structures limit their scale and scope of effectiveness even as they provide local alternatives for peacebuilding.
Effect of glass powder on microstructure of cement pastes
Authors: Liu Shuhua , Xie Guoshuai , Wang Shu
Published: May 2014

The effect of glass powder (GP) on the microstructure of cement pastes was studied by using mercury intrusion porosimetry, thermogravimetric and differential thermal analysis, scanning electron microscopy, energy dispersive spectrum analysis and X-ray diffraction techniques. The compressive strength and alkali–silica reaction (ASR) expansion was also tested. The test results indicated that GP can increase the compressive strength of cement pastes and control the ASR expansion of mortars. With the increase in GP content, ASR expansion decreases sharply, although compressive strength decreases a little with a large amount of GP. The characteristic pore sizes decreased with some capillary pores transforming to interstitial pores or gel pores as GP content increased. GP could diminish pore size in cement pastes, which has important significance in improving durability. Incorporating GP in cement-based materials had little effect on the kinds of hydration products, but it significantly affected the amount of hydrates, especially calcium hydroxide. The amount of calcium hydroxide reduces with the increase in curing age and GP content. The microstructure of hardened pastes containing GP was relatively dense with an abundance of calcium silicate hydrate, whose morphology was different from the gel in pure cement systems. This kind of calcium silicate hydrate gel with a low calcium/silicon ratio had a network structure formed by irregular stumpy and lamelliform gel granules. GP has high pozzolanic activity.
Delamination detection in buckling laminated composite plates
Authors: Rezaiee-Pajand Mohammad , Shahabian Farzad , Tavakoli Fariba Hassanzadeh
Published: May 2014

This paper introduces a new damage detection procedure for laminated composite plates with multiple through-the-width delaminations under compressive loading. The higher-order shear deformation theory is used for the higher-order finite-element formulation. A 13-node triangular element is introduced for finite-element modelling, which includes a parabolic variation of the transverse shear strains through the thickness. As a result, there is no need to use shear correction coefficients in computing the shear stresses. A virtual iso-parametric element is employed to avoid overlapping between delaminated areas. Moreover, w,n is used as an independent degree of freedom to obtain accurate responses and accelerate the rate of convergence in the finite-element analysis. A two-step genetic algorithm approach for delamination identification is also proposed, which can identify the location and magnitude of delamination in laminated composite plates under compressive loading. By minimising the difference between the analytical responses, resulting from the suggested formulation, and the measured responses, a genetic algorithm identifies the delamination. In this study, some examples are provided to illustrate the accuracy of the formulation.
Shear strength degradation in claystones due to environmental effects
Authors: PINEDA J.A. , ROMERO E. , DE GRACIA M. , SHENG D.
Published: May 2014

This note explores the influence of environmental effects, as those induced by cyclic changes in relative humidity, on the degradation of the shear strength parameters in Lilla claystone, a low-porosity clayey rock from northern Spain. The results of a comprehensive experimental programme, combining long-term relative humidity cycling tests with saturated direct shear tests, are described. A continuous monitoring of the evolution of volumetric strain during the previous relative humidity cycling is used to evaluate the swelling behaviour of the rock. Both undisturbed and degraded specimens are subjected to shearing at saturated conditions to determine the peak and post-rupture shear strength envelopes. The effects on rock brittleness and dilation angle are also analysed. Shear strength shows a strong dependence on the history of relative humidity cycling. In particular, the evolution of the peak shear strength parameters (c′ and φ′) seem to be related to the accumulated irreversible strains developed during each cycle. A damage law, recently proposed by the authors, is used to represent the progressive degradation of the shear strength parameters as a function of the accumulated irreversible strains.
Geographic coincidence of richness, mass, conservation value, and response to climate of U.S. land birds
Authors: Grundel Ralph , Frohnapple Krystalynn J. , Zaya David N. , Glowacki Gary A. , Weiskerger Chelsea J. , Patterson Tamatha A. , Pavlovic Noel B.
Published: May 2014

Distributional patterns across the United States of five avian community breeding‐season characteristics—community biomass, richness, constituent species' vulnerability to extirpation, percentage of constituent species' global abundance present in the community (conservation index, CI), and the community's position along the ecological gradient underlying species composition (principal curve ordination score, PC)—were described, their covariation was analyzed, and projected effects of climate change on the characteristics and their covariation were modeled. Higher values of biomass, richness, and CI were generally preferred from a conservation perspective. However, higher values of these characteristics often did not coincide geographically; thus regions of the United States would differ in their value for conservation depending on which characteristic was chosen for setting conservation priorities. For instance, correlation patterns between characteristics differed among Landscape Conservation Cooperatives. Among the five characteristics, community richness and the ecological gradient underlying community composition (PC) had the highest correlations with longitude, with richness declining from east to west across the contiguous United States. The ecological gradient underlying composition exhibited a demarcation near the 100th meridian, separating the contiguous United States grossly into two similar‐sized avian ecological provinces. The combined score (CS), a measure of species' threat of decline or extirpation, exhibited the strongest latitudinal pattern, declining from south to north. Over ∼75% of the lower United States, projected changes in June temperature and precipitation to year 2080 were associated with decreased averaged values of richness, biomass, and CI, implying decreased conservation value for birds. The two ecological provinces demarcated near the 100th meridian diverged from each other, with projected changes in June temperatures and precipitation from the year 2000 to 2080 suggesting increased ecological dissimilarity between the eastern and western halves of the lower United States with changing climate. Anticipated climate‐related changes in the five characteristics by 2080 were more weakly correlated with latitude or longitude then the responses themselves, indicating less distinct geographic patterns of characteristic change than in the characteristics themselves. Climate changes projected for 2080 included geographic shifts in avian biomass, CS, and PC values, a moderate overall decline in CI, and general decline in species richness per site.
Predictive modeling of marine benthic macrofauna and its use to inform spatial monitoring design
Authors: Dowd Michael , Grant Jon , Lu Lin
Published: May 2014

This study undertakes ecological analysis focused on predictive modelling and design for spatial sampling. The approaches are applied to a set of coastal marine benthic macrofaunal observations, and associated environmental data, measured at 48 sites in St Anns Bay, Nova Scotia, Canada. A multivariate generalized least‐squares regression was used to establish a predictive relationship between benthic fauna and the environment. Five ecological indices derived from faunal composition (abundance, richness, species number, diversity, AMBI) were treated as a multivariate response, and 10 environmental variables as candidate predictors. The multivariate regression also incorporated the effects of spatial autocorrelation. Predictive relationships were highly significant, and variable selection identified three key environmental predictors (median sediment grain size, porosity, and sulfide). Using these baseline data, we developed a procedure to identify a reduced sampling design for long‐term monitoring of benthic faunal health. The procedure is based on a sequential (backward elimination) algorithm to identify the set of sites that contributed most to the overall information. This study provides a general and comprehensive statistical framework for treating environmental monitoring and sampling design. It can be extended beyond the statistical framework used, and applied to a range of ecological applications.
Implementation of marine spatial planning in shellfish aquaculture management: modeling studies in a Norwegian fjord
Authors: Filgueira Ramón , Grant Jon , Strand Øivind
Published: May 2014

Shellfish carrying capacity is determined by the interaction of a cultured species with its ecosystem, which is strongly influenced by hydrodynamics. Water circulation controls the exchange of matter between farms and the adjacent areas, which in turn establishes the nutrient supply that supports phytoplankton populations. The complexity of water circulation makes necessary the use of hydrodynamic models with detailed spatial resolution in carrying capacity estimations. This detailed spatial resolution also allows for the study of processes that depend on specific spatial arrangements, e.g., the most suitable location to place farms, which is crucial for marine spatial planning, and consequently for decision support systems. In the present study, a fully spatial physical‐biogeochemical model has been combined with scenario building and optimization techniques as a proof of concept of the use of ecosystem modeling as an objective tool to inform marine spatial planning. The object of this exercise was to generate objective knowledge based on an ecosystem approach to establish new mussel aquaculture areas in a Norwegian fjord. Scenario building was used to determine the best location of a pump that can be used to bring nutrient‐rich deep waters to the euphotic layer, increasing primary production, and consequently, carrying capacity for mussel cultivation. In addition, an optimization tool, parameter estimation (PEST), was applied to the optimal location and mussel standing stock biomass that maximize production, according to a preestablished carrying capacity criterion. Optimization tools allow us to make rational and transparent decisions to solve a well‐defined question, decisions that are essential for policy makers. The outcomes of combining ecosystem models with scenario building and optimization facilitate planning based on an ecosystem approach, highlighting the capabilities of ecosystem modeling as a tool for marine spatial planning.
The Role of Alcohol Use During Sexual Situations in the Relationship Between Sexual Revictimization and Women’s Intentions to Engage in Unprotected Sex
Authors: Parkhill Michele R. , Norris Jeanette , Davis Kelly Cue
Published: May 2014

Research has demonstrated relationships among childhood sexual abuse, adult sexual assault, and sexual risk taking. This study proposes that one mechanism through which the victimization–sexual risk-taking relationship works is through an increased likelihood of drinking during sexual situations. Using path analysis, this study explores this hypothesis in a sample of 230 women. The model illustrates that women with a history of child and adult sexual victimization reported greater intentions to engage in unprotected sex and that this relationship is in part accounted for by an increased likelihood of drinking in sexual situations. The results suggest that sexual risk reduction programs and sexual assault treatment programs should educate women about the alcohol-involved sexual risk taking that often follows sexual assault victimization.