Essays on macroeconomics

McKay, Alisdair Graham Princeton University 2010 해외박사(DDOD)

In chapter 1, coauthored with Ricardo Reis, we systematically investigate the claim that contractions in economic activity are briefer (shorter) and more violent (rapid) than expansions. In the process we discover a robust new business cycle fact: contractions in employment are briefer and more violent than expansions but we cannot reject equal brevity and violence for output fluctuations. Existing business cycle models cannot fully account for this fact. We then show that a business cycle model with asymmetric adjustment costs on employment and a choice of when to scrap old technologies can account for the business cycle fact both qualitatively and quantitatively. 1. Chapter 2 is motivated by empirical studies of household financial decisions that suggest households are heterogeneous in their abilities to make sound financial choices. I develop a general equilibrium model of household saving behavior in which the quality of financial decisions is endogenously determined by the incentives to exert effort in learning about financial opportunities. The model embeds an equilibrium search setting in the asset market of a heterogeneous-agent savings model. The model's predictions for asset market participation, portfolio returns and financial planning behavior are consistent with the data on average and across households. I use the model to analyze a partial privatization of the social security system. After privatization, households have larger portfolios and stronger incentives to search for assets. The increase in search effort increases the participation rate and results in a more competitive asset market. Chapter 3 considers regulation of retail financial markets in a setting similar to that of chapter 2. In a model in which consumers of financial services must pay an information cost or otherwise exert some effort to make a well-informed choice, regulations that attempt to suppress the supply of low-quality financial offers can have perverse effects as they blunt the incentives for consumers to become informed. In contrast, policies that strive to promote information seeking on the part of consumers improve the quality of offered contracts and improve welfare without the potential for these perverse effects to occur. 1A version of this work was published in the Journal of Monetary Economics. See McKay, Alisdair and Reis, Ricardo. 2008. "The brevity and violence of contractions and expansions." Journal of Monetary Economics, 55(4), 738-751.

OIL WEALTH AS A FACILITATOR OF REGIME STABILITY

Anita Mckay 韓國外國語大學校 國際地域大學院 2015 국내석사

OIL WEALTH AS A FACILITATOR OF REGIME STABILITY: A COMPARATIVE ANALYSIS OF POLITICAL UPRISINGS IN SAUDI ARABIA The Arab Spring changed the political landscape of the Middle East. Driven by socio-economic inequalities, mass demonstrations calling for reforms took place throughout the region and ousted the leaders of Egypt, Libya and Tunisia posing a direct threat to the stability of Al Saud monarchy in Saudi Arabia. Despite suffering from the same socio-economic inequalities Saudi Arabia witnessed little dissent and the regime remains stable. This thesis examines how the Al Saud uses its oil wealth to curb large-scale opposition from occurring. By comparing two separate uprisings that posed a direct threat to the regimes survival this thesis finds that the Al Saud is reliant on both oil wealth and a harsh security apparatus for its stability and that the regime uses its oil wealth to placate dissent when opposition is a direct threat to its stability.

MOSAN RELIQUARY TRIPTYCHS AND THE CULT OF THE TRUE CROSS IN THE TWELFTH CENTURY (STAVELOT TRIPTYCH, STE. CROIX TRIPTYCH, DUTUIT TRIPTYCHS, GUENNOL TRIPTYCH)

HOLBERT, KELLY MCKAY Yale University 1995 국내박사

Securing commitment in an insecure world: Power and the social regulation of labor in the Philippine electronics industry

McKay, Steven Charles The University of Wisconsin - Madison 2001 해외박사(DDOD)

Changes in the nature and intensity of global competition have re-ignited debates over the organization of work and its consequences for workers. This study takes up core sociological issues of work, power and inequality but within the contemporary context of advanced multinational electronics manufacturing in Philippine economic zones. The study finds that restructuring has led to a more complex market competition, in which firms investing abroad seek uniquely-skilled labor pools and particular regulatory regimes. The Philippine state has responded by consciously re-designing export processing zones, from de-regulated public export platforms to selectively-regulated private high-tech enclaves. Competitive pressures have also increasingly pushed firms to reorganize work and foster commitment among employees. But rather than cultivating commitment to empower workers, firms in the study secure worker commitment in order to reinforce workplace control. And contrary to prevailing “best practice” theories, firms pursue divergent paths to achieve both competitiveness and commitment. Based on qualitative field research in the Philippines, the study traces four distinct ways of organizing work and commitment: the despotic, the panoptic, the individually-negotiated, and the collectively-negotiated work systems. These systems are analyzed through case studies of four multinational electronics firms, their workers, and their localization strategies. To secure commitment, firms may provide some positive incentives, such as higher pay and better benefits. But they may also leverage workers' vulnerabilities in the local labor market, tap into informal institutions of social control, and manipulate non-economic inequalities formed outside the workplace. The study also finds that competitive performance does <italic>not</italic> require radical shifts in organizational hierarchies or genuine participation by a broadly-skilled workforce. Indeed, innovations in high-tech production have seemed to <italic> widen</italic> the skills gap between technical and non-technical workers and <italic>reduce</italic> the autonomy of production operators. The complexities of work organization strategies, state regulation and labor market segmentation contribute to the difficulty of worker organization and collective political mobilization and call for a theoretical re-examination of approaches to work and commitment that neglect issues of power and inequality.

Neuromechanical constraints and optimality for balance

McKay, Johnathan Lucas Georgia Institute of Technology 2010 해외박사(DDOD)

Although people can typically maintain balance on moving trains, or press the appropriate button on an elevator with little conscious effort, the apparent ease of these sensorimotor tasks is courtesy of neural mechanisms that continuously interpret many sensory input signals to activate muscles throughout the body. The overall hypothesis of this work is that motor behaviors emerge from the interacting constraints and features of the nervous and musculoskeletal systems. The nervous system may simplify the control problem by recruiting muscles in groups called muscle synergies rather than individually. Because muscles cannot be recruited individually, muscle synergies may represent a neural constraint on behavior. However, the constraints of the musculoskeletal system and environment may also contribute to determining motor behaviors, and so must be considered in order to identify and interpret muscle synergies. Here, I integrated techniques from musculoskeletal modeling, control systems engineering, and data analysis to identify neural and biomechanical constraints that determine the muscle activity and ground reaction forces during the automatic postural response (APR) in cats. First, I quantified the musculoskeletal constraints on force production during postural tasks in a detailed, 3D musculoskeletal model of the cat hindlimb. I demonstrated that biomechanical constraints on force production in the isolated hindlimb do not uniquely determine the characteristic patterns of force activity observed during the APR. However, when I constrained the muscles in the model to activate in a few muscle synergies based on experimental data, the force production capability drastically changed, exhibiting a characteristic rotation with the limb axis as the limb posture was varied that closely matched experimental data. Finally, after extending the musculoskeletal model to be quadrupedal, I simulated the optimal feedforward control of individual muscles or muscle synergies to regulate the center of mass (CoM) during the postural task. I demonstrated that both muscle synergy control and optimal muscle control reproduced the characteristic force patterns observed during postural tasks. These results are consistent with the hypothesis that the nervous system may use a low-dimension control scheme based on muscle synergies to approximate the optimal motor solution for the postural task given the constraints of the musculoskeletal system. One primary contribution of this work was to demonstrate that the influences of biomechanical mechanisms in determining motor behaviors may be unclear in reduced models, a factor that may need to be considered in other studies of motor control. The biomechanical constraints on force production in the isolated hindlimb did not predict the stereotypical forces observed during the APR unless a muscle synergy organization was imposed, suggesting that neural constraints were critical in resolving musculoskeletal redundancy during the postural task. However, when the model was extended to represent the quadrupedal system in the context of the task, the optimal control of the musculoskeletal system predicted experimental force patterns in the absence of neural constraints. A second primary contribution of this work was to test predictions concerning muscle synergies developed in theoretical neuromechanical models in the context of a natural behavior, suggesting that these concepts may be generally useful for understanding motor control. It has previously been shown in abstract neuromechanical models that low-dimension motor solutions such as muscle synergies can emerge from the optimal control of individual muscles. This work demonstrates for the first time that low-dimension motor solutions can emerge from optimal muscle control in the context of a natural behavior and a realistic musculoskeletal model. This work also represents the first explicit comparison of muscle synergy control and optimal muscle control during a natural behavior. It demonstrates that an explicit low-dimension control scheme based on muscle synergies is competent for performance of the postural task across biomechanical conditions, and in fact, may approximate the motor solution predicted by optimal muscle control. This work advances our understanding how the constraints and features of the nervous and musculoskeletal systems interact to produce motor behaviors. In the future, this understanding may inform improved clinical interventions, prosthetic applications, and the general design of distributed, hierarchal systems.

Learning Alters the Afterhyperpolarization in Hippocampus CA1 Pyramidal Neurons and Interneurons

McKay, Bridget Marie Northwestern University 2013 해외박사(DDOD)

Neuronal intrinsic excitably, commonly indexed by the amplitude of the afterhyperpolarization (AHP), is a well-established correlate of learning. Previous studies regarding this relationship have utilized learning tasks that require a large number of trials, have used somatic rather than synaptic stimulation, and have focused exclusively on principal neurons. For this series of studies, rats and mice were trained at trace fear conditioning (in which learning is acquired after few trials) or trace eyeblink conditioning (in which learning takes place over many trials). Although mice used came from the FVB strain, a thorough behavioral battery appropriate for blind mice ascertained that they learned the eyeblink conditioning task. Twenty four hours after the final training session, whole cell patch clamp recordings were made from pyramidal neurons and interneurons. The AHP was elicited using somatic and synaptic stimulation. Increased intrinsic excitability was observed following trace fear conditioning, indicating that AHP alterations can take place more quickly than previously demonstrated. In addition, learning-related increases in intrinsic excitability were observed following AHPs elicited with synaptic stimulation, indicating that these changes take place with a more physiologically relevant calcium entry profile. Learning also caused a global increase in synaptically evoked inhibition. This is due in part to an increase in intrinsic excitability in somatostatin-positive interneurons following learning, and is mediated by reduced current flow through calcium-dependent small-conductance potassium (SK) channels. In addition, in vivo infusion of SK channel agonists reduced spontaneous firing rate and retarded acquisition of trace eyeblink conditioning. Together, these data suggest that alterations in calcium-dependent potassium channel activity are a mechanism shared by pyramidal neurons and interneurons in order to enhance intrinsic excitability to support learning and memory. These data additionally suggest that learning is accompanied by an increase in both excitation and inhibition. As the hippocampus is a structure in which too much excitation is possible and detrimental, an increase in inhibition may serve to protect from seizure activity. Alternatively, an increase in both excitation and inhibition may be integral to the learning process itself. It may serve to improve spike-timing precision, center-surround signal to noise, and/or neuronal synchrony during learning.

The effects of stratification on the quasigeostrophic, double-gyre, wind-driven ocean circulation

McKay, Cavendish Q The University of Wisconsin - Madison 2005 해외박사(DDOD)

I investigate the effects of varying the stratification parameters of one and two layer quasigeostrophic models on the wind driven ocean circulation. The double-gyre wind-driven ocean circulation has been widely studied in an attempt to understand the internal variability present in the ocean. In recent years, the machinery of dynamical systems theory has been applied to the problem, and has met with considerable success in diagnosing some of the variability in simple layer models. However, the sensitivity of these models to the shape and strength of the ocean stratification has been largely ignored. This study is an effort to address this lack of attention. Using the results of a barotropic quasigeostrophic model as a baseline case, the sensitivity of a reduced gravity quasigeostrophic model to the strength of stratification, and the sensitivity of a two-layer quasigeostrophic model to the strength and shape of stratification are explored. The effects of stratification strength vary slightly between the reduced gravity and two-layer models. In both models, weaker stratification leads to longer timescales and more regular oscillations, and shifts the parameter ranges in which steady, periodic, and aperiodic states appear. If the dissipation takes the form ∇2q, rather than ∇4psi, the stratification strength also has effects related to the strength of the interfacial friction. In the reduced gravity model, this additional friction term serves to extract energy from the system, while in the two layer model, it transfers energy between the layers. The two layer model also has a parameter describing the shape of the stratification. This parameter, the layer thickness ratio delta, affects the balance of the forcing on the barotropic and baroclinic modes of the system, as well as affecting the relative scaling of the nonlinear interactions between those modes. A deeper upper layer leads to increased variability, regardless of whether one holds the forcing on the barotropic or baroclinic mode fixed.

Individual differences in Theory of Mind and narrative in early adulthood

McKay, Mary Ellen University of Florida 2013 해외박사(DDOD)

Theory of Mind (ToM) can be understood as the uniquely human social cognitive ability to reason about the complex mental states of the self and of others. ToM has typically been studied as a skill that develops across early childhood. Current research is directed at further understanding the development and the processes ToM through the study of adults. Historically, social cognition in adulthood has been studied separately from child social cognition. This study attempted to bridge the gap between the child and adult literature on social cognition by exploring relationships among a variety of tasks used in both of these literatures. Specific aims of the present study were as follows: (1) to examine whether there is an underlying ToM factor comprised of Reading the Mind in the Eyes, hindsight bias, and curse of knowledge in adulthood; (2) to examine whether language and inhibitory control (IC) are related to ToM; (3) to examine the role of these factors for story quality; and (4) to test a mediation model of the indirect effect of language and IC on story quality through ToM. Results indicated that the three factors included as indices of ToM did not correlate with one another. Regression analyses support the ongoing role of inhibitory control for ToM in everyday life, but did not provide strong evidence of the ongoing role of language for adult ToM. ToM was found to be significantly related to the quality of socially shared stories, fictional and autobiographical in nature. Inhibitory control may have an indirect effect on story quality through ToM. Essentially, adults apply cognitive effort in inhibiting their own perspectives when communicating with others who have different perspectives. Results are discussed in light of the most current theoretical viewpoints emerging in the growing literature describing ToM in adulthood as well as their implications in understanding classic views of child cognitive development, specifically Vygotsky's socio-cultural theory.

A scar on the surface of God: Translating biblical allusion in Modern Hebrew poetry

McKay, Rebecca Mara The University of Iowa 2009 해외박사(DDOD)

In this dissertation, I translate a selection of poems from Modern Hebrew that contain biblical allusions, and I present that selection in "chronological" order---that is, following the order of the biblical narratives they allude to, thereby creating a retelling of the Hebrew Bible through Modern Hebrew poetry. I preface the selection with a introduction that examines the role of biblical allusion in the development of Hebrew poetry in the twentieth century and contrasts the work of poets writing in Hebrew with three poets writing in English who use biblical allusion (Charles Reznikoff, Anthony Hecht, and Jacqueline Osherow). I also offer a detailed analysis of the challenges particular to translating biblical allusion poetry. These challenges include register mixing, paronomasia, biblical poetics, and references that are unfamiliar to readers without a background in Biblical Hebrew, Israeli history, or Jewish customs and practices.

Effects of altered sensory information during posture and gait: A developmental perspective

McKay, Sandra M University of Michigan 2006 해외박사(DDOD)

In young adults, the role of Ia primary muscle spindles from the gastroc-soleus have been investigated extensively during quiet standing and are considered important contributors to the maintenance of quiet stance. The Ia primary muscle spindles may play a limited influence on the modulation of muscle activity during the stance phase of gait for young adults. An investigation into the contribution of Ia primary muscle spindles to the control of postural stability and gait in children between the ages of 5--7 and 9--11 years of age was completed. During the postural task afferent information was manipulated via unilateral tendon vibration with and without visual information. In general, the perturbation of the proprioceptive information during the postural control task was more destabilizing to the children compared to the young adults, particularly when vision was occluded. Based on the current findings it was not definitive that peripheral factors contributed significantly to postural differences observed between children and adults. However, several centrally mediated factors, such as difficulty reweighing sensory inputs, delayed muscle onsets and inefficient muscle activity, were considered attractive and plausible explanations contributing to the differences observed between children and adults. During the walking task, vision was always available and vibration was briefly applied during the swing and stance phases or continuously throughout the gait cycle. The principal findings related to the walking study involved the modulation of plantarflexor muscle activity during the stance phase for the children and not the young adults, and a greater number of alterations to the walking characteristics during the continuous vibration condition for the children when compared to the young adults. The modulation of muscle activity during the stance phase for the children suggests peripheral factors specific to the phasic gating of sensory information appears to be different for children than young adults during walking. While the differences observed between the children and young adults during the continuous vibration condition are suggestive of difficulties with centrally mediated processes potentially related to the ability to flexibility manage, extract, and process afferent inputs.