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Anterior Prefrontal Contributions to Implicit Attention Control  [PDF]
Stefan Pollmann
Brain Sciences , 2012, DOI: 10.3390/brainsci2020254
Abstract: Prefrontal cortex function has traditionally been associated with explicit executive function. Recently, however, evidence has been presented that lateral prefrontal cortex is also involved in high-level cognitive processes such as task set selection or inhibition in the absence of awareness. Here, we discuss evidence that not only lateral prefrontal cortex, but also rostral prefrontal cortex is involved in such kinds of implicit control processes. Specifically, rostral prefrontal cortex activation changes have been observed when implicitly learned spatial contingencies in a search display become invalid, requiring a change of attentional settings for optimal guidance of visual search.
Implicit and Explicit Contributions to Object Recognition: Evidence from Rapid Perceptual Learning  [PDF]
Ulla Martens, Patricia Wahl, Uwe Hassler, Uwe Friese, Thomas Gruber
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0047009
Abstract: The present study investigated implicit and explicit recognition processes of rapidly perceptually learned objects by means of steady-state visual evoked potentials (SSVEP). Participants were initially exposed to object pictures within an incidental learning task (living/non-living categorization). Subsequently, degraded versions of some of these learned pictures were presented together with degraded versions of unlearned pictures and participants had to judge, whether they recognized an object or not. During this test phase, stimuli were presented at 15 Hz eliciting an SSVEP at the same frequency. Source localizations of SSVEP effects revealed for implicit and explicit processes overlapping activations in orbito-frontal and temporal regions. Correlates of explicit object recognition were additionally found in the superior parietal lobe. These findings are discussed to reflect facilitation of object-specific processing areas within the temporal lobe by an orbito-frontal top-down signal as proposed by bi-directional accounts of object recognition.
Tariffs and Total Factor Productivity: The Case of Ghanaian Manufacturing Firms  [PDF]
Charles Ackah, Ernest Ernest Aryeetey, Oliver Morrissey
Modern Economy (ME) , 2012, DOI: 10.4236/me.2012.33037
Abstract: This paper investigates the effects of trade liberalization on firm productivity in Ghana. We examine Ghanaian trade policy from 1993 to 2002, a period during which trade liberalization deepened with intermittent protection in a number of ways across industries, to investigate the effects of trade policy reforms and firm productivity. We find a strong negative impact of nominal tariffs on firm productivity, controlling for observed and unobserved firm characteristics and industry heterogeneity, a result that is robust to various alterations of the base model, including treating tariffs as endogenous and employing different estimation techniques. These results indicate that firms that are overprotected have a lower level of Total Factor Productivity than firms that are exposed to import competition. The estimated coefficients on both tariffs and its squared term confirm that higher tariffs are particularly distortionary.
Vertical integration, collusion, and tariffs
Pedro Mendi,Rafael Moner-Colonques,José J. Sempere-Monerris
SERIEs , 2011, DOI: 10.1007/s13209-010-0034-3
Abstract: This article presents a link between tariff rates and industry structure in a dynamic setting. We examine the role of tariffs on final-goods in a firm’s decision to integrate and collude in the presence of competitive imports. It is shown that, under some conditions, the upstream firm has an incentive to engage in vertical integration to introduce profitably a wholesale price above the world input price while not inducing any intermediate or final good imports. Higher tariffs downstream, even with no tariff protection upstream, make this strategy more profitable, and provide a rationale for a positive relationship between tariff protection and vertical integration, which is observed in some industries.
Identifying temporal and causal contributions of neural processes underlying the Implicit Association Test (IAT)  [PDF]
Chad E. Forbes,Katherine A. Cameron,Jordan Grafman,Aron Barbey,Jeffrey Solomon,Walter Ritter,Daniel S. Ruchkin
Frontiers in Human Neuroscience , 2012, DOI: 10.3389/fnhum.2012.00320
Abstract: The Implicit Association Test (IAT) is a popular behavioral measure that assesses the associative strength between outgroup members and stereotypical and counterstereotypical traits. Less is known, however, about the degree to which the IAT reflects automatic processing. Two studies examined automatic processing contributions to a gender-IAT using a data driven, social neuroscience approach. Performance on congruent (e.g., categorizing male names with synonyms of strength) and incongruent (e.g., categorizing female names with synonyms of strength) IAT blocks were separately analyzed using EEG (event-related potentials, or ERPs, and coherence; Study 1) and lesion (Study 2) methodologies. Compared to incongruent blocks, performance on congruent IAT blocks was associated with more positive ERPs that manifested in frontal and occipital regions at automatic processing speeds, occipital regions at more controlled processing speeds and was compromised by volume loss in the anterior temporal lobe (ATL), insula and medial PFC. Performance on incongruent blocks was associated with volume loss in supplementary motor areas, cingulate gyrus and a region in medial PFC similar to that found for congruent blocks. Greater coherence was found between frontal and occipital regions to the extent individuals exhibited more bias. This suggests there are separable neural contributions to congruent and incongruent blocks of the IAT but there is also a surprising amount of overlap. Given the temporal and regional neural distinctions, these results provide converging evidence that stereotypic associative strength assessed by the IAT indexes automatic processing to a degree.
On the Optimal Trade Tariffs among Nations
Luis F. Copertari
Open Access Library Journal (OALib Journal) , 2018, DOI: 10.4236/oalib.1104641
An optimization model for calculating trade tariffs based on the idea of a zero-balanced trade account for countries around the world is proposed. Specifically, countries in the G20 group of nations were analyzed. The results are scrutinized and reflected upon, and some ideas about policy to follow are proposed. Both the mercantilist and Keynesian points of view are considered.
Bribe-Giving and Endogenous Partnership in Oligopolies: Some Theoretical Conjectures  [cached]
Partha Gangopadhyay,Jenny Zhang,Mark Zreika
Modern Applied Science , 2012, DOI: 10.5539/mas.v6n4p2
Abstract: As stories of bribe-giving, like corporate contributions to campaign funds and Enron scandals, continue to rock the corporate world, it is imperative that implication of such activities on long-term market outcomes is evaluated. Can bribe-giving have long-term and far-reaching consequences for an oligopolistic market? In this paper we attempt to provide an answer to this question by developing a simple duopoly model that characterizes a perfect Nash equilibrium of bribe-giving. This allows us to establish some perplexing comparative static properties of the market equilibrium. The primary intuition behind our results is that bribe-giving can have serious impacts on the long-run equilibrium of an oligopoly through their effects on the incentives of and constraints on individual firms to form alliances, or partnerships. Bribe-giving, through its effects on individual costs, can trigger a series of endogenously-driven changes in an industry. One of the key changes is the endogenous formation of business alliances (also known as endogenous mergers), which is driven by changes in costs as a direct consequence of bribes. We construct a model of endogenous mergers, to our understanding for the first time, to shed some light on the incentives of firms to endogenously merge in the context of bribe-giving. We show that this can seriously influence the welfare of market participants.
Profit-Improving Linear Tariffs Pricing in a Vertical Oligopoly  [PDF]
Dong Joon Lee, Sangheon Han, Yuji Ono, Shigetsune Yamoto
Theoretical Economics Letters (TEL) , 2018, DOI: 10.4236/tel.2018.811134
Abstract: Considering the interplay between intra-firms (own retailing firms) and inter-firms (rival retailing firms) competition in vertically related markets, we compare linear tariffs and two-part tariffs pricing. In contrast to previous results, we show that when both products are sufficiently close substitutes, there is a threshold level of the number of retailing firms, beyond which each manufacturing firms profits are larger under linear tariffs pricing than under two-part tariffs pricing. It shows the contradictions to the conventional wisdom that two-part tariffs pricing is always better than linear tariffs pricing from the viewpoint of manufacturing firms. We also show that the wholesale prices increase as the number of retailing firms increases under two-part tariffs pricing, regardless of the degree of product substitutability.
Contributions of primary and secondary biogenic VOC tototal OH reactivity during the CABINEX (Community Atmosphere-Biosphere INteractions Experiments)-09 field campaign  [PDF]
S. Kim,A. Guenther,T. Karl,J. Greenberg
Atmospheric Chemistry and Physics (ACP) & Discussions (ACPD) , 2011, DOI: 10.5194/acp-11-8613-2011
Abstract: We present OH reactivity measurements using the comparative reactivity method with a branch enclosure technique for four different tree species (red oak, white pine, beech and red maple) in the UMBS PROPHET tower footprint during the Community Atmosphere Biosphere INteraction EXperiment (CABINEX) field campaign in July of 2009. Proton Transfer Reaction-Mass Spectrometry (PTR-MS) was sequentially used as a detector for OH reactivity and BVOC concentrations including isoprene and monoterpenes (MT) for enclosure air. Therefore, the measurement dataset contains both measured and calculated OH reactivity from well-known BVOC. The results indicate that isoprene and MT, and in one case a sesquiterpene, can account for the measured OH reactivity. Significant discrepancy between measured OH reactivity and calculated OH reactivity from isoprene and MT is found for the red maple enclosure dataset but it can be reconciled by adding reactivity from emission of a sesquiterpene, α-farnesene, detected by GC-MS. This leads us to conclude that no significant unknown BVOC emission contributed to ambient OH reactivity from these trees at least during the study period. However, this conclusion should be followed up by more comprehensive side-by-side intercomparison between measured and calculated OH reactivity and laboratory experiments with controlled temperature and light environments to verify effects of those essential parameters towards unknown/unmeasured reactive BVOC emissions. This conclusion leads us to explore the contribution towards ambient OH reactivity (the dominant OH sink in this ecosystem) oxidation products such as hydroxyacetone, glyoxal, methylglyoxal and C4 and C5-hydroxycarbonyl using recently published isoprene oxidation mechanisms (Mainz Isoprene Mechanism II and Leuven Isoprene Mechanism). Evaluation of conventionally unmeasured first generation oxidation products of isoprene and their possible contribution to ambient missing OH reactivity indicates that the ratio of OH reactivity from unmeasured products over OH reactivity from MVK + MACR is strongly dependent on NO concentrations. The unmeasured oxidation products can contribute ~7.2 % (8.8 % from LIM and 5.6 % by MIM 2 when NO = 100 pptv) of the isoprene contribution towards total ambient OH reactivity. This amount can explain ~8.0 % (9.7 % from LIM and 6.2 % from MIM 2) of missing OH reactivity, reported by Di Carlo et al. (2004) at the same site. Further study on the contribution from further generation of unmeasured oxidation products is needed to constrain tropospheric photochemical reactivit
Tariffs Ranking in Mixed Oligopoly with Revenue Constraint  [PDF]
Leonard F. S. Wang,Jean Wang,Long Tang,Jen-Yao Lee
Economics Research International , 2011, DOI: 10.1155/2011/147357
Abstract: Utilizing linear mixed oligopoly model, this paper explores the magnitude of the maximum-revenue tariff, optimum-welfare tariff, and revenue-constrained optimal tariff that is especially designed for the consideration of the bureaucratic inefficiency. In particular, the tariff ranking issue is examined under both cases of Cournot competition and domestic public leadership. We found that, under Cournot competition, the optimum-welfare tariff is the highest and it is followed by the revenue-constrained optimal tariff while the maximum-revenue tariff is the lowest. But, under Stackelberg public leadership, if the domestic private firms are fewer than the foreign firms, the maximum-revenue tariff becomes the highest and the optimum-welfare exceeds the revenue-constrained optimal tariff. 1. Introduction Whether to apply maximum revenue tariffs or optimum welfare tariffs is interesting and should be deliberated because the tariff revenue is an important income source of a government before building up an efficient tax system. However, a government may adjust its goal from maximum-revenue to optimum-welfare along with economic improvement and the need for fiscal reform. In traditional tariff analyses, Johnson [1] argued that the maximum-revenue tariff is higher than the optimum-welfare tariff because a “large” country could change the terms of trade in order to raise its social welfare. From the strategic trade aspect, Brander and Spencer [2] showed that a government could improve its terms of trade through using tariff as a strategic instrument in an oligopoly market to take a leading position for transferring foreign firm’s revenue to a domestic firm. Collie [3] demonstrated that, in a Cournot duopoly market with linear demand and an asymmetric constant marginal cost, the optimum welfare tariff exceeds the maximum revenue if the domestic and foreign firm’s marginal costs are equal. Larue and Gervais [4] allowed an asymmetric number of domestic and foreign firms and showed that, if the numbers of domestic firms and foreign firms are the same, the maximum-revenue tariff is higher than the optimum-welfare tariff. Clarke and Collie [5] found that, in a Bertrand competition model, the optimum-welfare tariff is higher than the maximum-revenue tariff when the products are highly substitutable. Wang et al. [6] introduced market share delegation in a trade duopoly context and demonstrated that the home government unambiguously imposes a higher optimum-welfare tariff than maximum-revenue one regardless of the form of delegation. Wang et al. [7–9] reexamined the tariff
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