Exogenous Events Research Articles

The Impact of Forced Migration on Modern Cities: Evidence from 1930s Crop Failures

We find that a sizable portion of current city-level variation in unionization was set in place during the 1930s, and that this exogenous unionization has a real impact on city-level economic outcomes today. First, we show that the driving factor behind these city-level differences was random, and a result of substantially different rainfall levels during the Dust Bowl. We find that individuals in drought - ridden areas were significantly more likely to migrate to close-by cities. Workers in these cities - facing an influx of rural migrants - then became far more inclined to unionize than those facing less competition for their jobs. Using this rainfall (and the resultant crop failures) in surrounding counties to generate exogenous variation in city migration inflows, we show that random differences in the drought-laden 1930’s rainfall predict migration patterns, and variation in union formation rates that persist through today. These exogenous events explaining a sizable percentage of cross-sectional geographic variation in current unionization challenges explanations of unionization as a necessary response to work-place conditions. Furthermore, and importantly, we show that this exogenous unionization that persists through today predicts variation in key city-level economic outcomes such as level of education, establishment growth, and the presence of high-value industries.

HOUSEHOLD EXPENDITURE IN RESPONSE TO NATURAL DISASTERS

Natural disasters have increased in their frequency, and the intensity of their destruction over the last ten years in Indonesia. Households usually respond to these difficulties by cutting their consump-tion, especially for non-essential goods. Arguably natural disasters are exogenous events, so this paper uses the exogenous variation from natural disasters as a natural experiment design to estimate the effect of disasters on household expenditure. When a certain group is exposed to the causal variable of interest, such as a disaster, and other groups are not, the Difference In Difference model (DID) can be used for estimation. Using a micro level survey data set from the Indonesian Family Life Survey (IFLS) which covers approximately 83 percent of the Indonesian population within the survey area, this paper examines the effects of natural disasters on household expenditure. This paper also examines whether there are any different impacts from different types of disasters. The finding is there are no significant effects of disasters on total household expenditure for households living in disaster regions, whether they are affected directly or not by the disaster.Keywords: natural disasters, household expenditure, DID, natural experiment

Migration policy reforms in the context of economic and political crises: the case of Belgium

ABSTRACTA body of literature has examined the role of ‘crises’ on policy-making. Yet, we observe that endogenous or exogenous events called ‘crisis-events’ are often randomly chosen as sweeping explanations for reforms in migration and integration policy. Thus, we attempt to find answers for the question of how the latest financial and economic crisis affected policy-making in the area of migration and integration. We apply a combination of interest-based and ideas-based theories to the case of Belgium in order to question the role of crises in policy reforms in the field of migration and integration. Multiple political and economic crises have affected the country since 2007. Examining these crises and immigration politics we argue that electoral competition both between and within the Francophone and Flemish party systems continues to be the main driver of migration and integration policy reform. Yet, we also discover a cumulative effect of economic and political crises: while the intention of restricting immigration has remained largely unchanged over the years, the policy instruments employed to reach this objective have changed with the political and economic crises.

Performance growth and opportunistic marketing spending

Marketing executives are under pressure to produce revenue and profit growth for their brands. In most cases that involve requesting gradually higher marketing budgets, which is expensive, especially considering the known diminishing return effects of marketing. However, in reality, brand sales tend to evolve not gradually, but rather in spurts, i.e. short periods of sales evolution alternating with longer periods of stability. We use the Wang–Zhang (2008) time-series test to identify such growth spurt periods, which represent opportunity windows for the benefitting brand. We then relate these windows to exogenous events such as positive product reviews, which create a temporarily more benevolent environment for the brand. We suggest brand managers be vigilant to catch and take advantage of such opportunity windows to generate sustained growth at low cost, and derive the implications of such vigilant spending for marketing budget setting. Our empirical illustration is based on several brands in the digital single-lens reflex (DSLR) camera market. It demonstrates, among other things, that competitors in this market typically do not take advantage of windows of growth opportunity offered by positive product reviews.

Domain-independent planning for services in uncertain and dynamic environments

Research in automated planning provides novel insights into service composition and contributes towards the provision of automatic compositions which adapt to changing user needs and environmental conditions. Most of the existing planning approaches to aggregating services, however, suffer from one or more of the following limitations: they are not domain-independent, cannot efficiently deal with numeric-valued variables, especially sensing outcomes or operator inputs, and they disregard recovery from runtime contingencies due to erroneous service behavior or exogenous events that interfere with plan execution. We present the RuGPlanner, which models the planning task as a Constraint Satisfaction Problem. In order to address the requirements put forward by service domains, the RuGPlanner is endowed with a number of special features. These include a knowledge-level representation to model uncertainty about the initial state and the outcome of sensing actions, and efficient handling of numeric-valued variables, inputs to actions or observational effects. In addition, it generates plans with a high level of parallelism, it supports a rich declarative language for expressing extended goals, and allows for continual plan revision to deal with sensing outputs, failures, long response times or timeouts, as well as the activities of external agents. The proposed planning framework is evaluated based on a number of scenarios to demonstrate its feasibility and efficiency in several planning domains and execution circumstances which reflect concerns from different service environments.

Do Female Executives Prioritize Corporate Social Responsibility?

How do female executives view corporate social responsibility (CSR) policy? Previous studies have report mixed findings on the relationship between female executives and CSR policy. On the basis of a sample of Chinese listed firms, we use propensity score matching to construct a new sample of firms to evaluate the gender transition (from male to female) of CEOs or board chairpersons (executives) randomly assigned to firms (i.e., the gender transition of executives is treated as an exogenous event). Subsequently, we use a difference-in-differences approach to identify the pure effect of female executives on CSR. Our estimates indicate that, compared with their male counterparts, female executives are more likely to encourage CSR reporting and are more likely to strengthen the content of CSR statements. Furthermore, we find that female executives prioritize reporting CSR aspects in the order of shareholders protection, staff protection, delivery protection, customer protection, environmental protection, and public relations.

More Eyes, (No Guns,) Less Crime: Estimating the Effects of Unarmed Private Patrols on Crime Using a Bayesian Structural Time-Series Model

textabstractThis work studies the effect of unarmed private security patrols on crime. We make use of a initiative, triggered by an arguably exogenous events, consisting in hiring unarmed private security agents to patrol, observe and report to ordinary police criminal activities within a well-defined city area. Our identification strategy capitalizes on the fact that the portions of the city outside the arbitrarily defined intervention area remain unaffected by the patrolling activity. To estimate the effects of the security patrols, we use both a difference-in-difference approach and we additionally propose the first application in Law & Economics of a Bayesian structural time-series model (Brodersen et al., 2015). This model overcomes some limitations and provides a generalization to the time-series setting of the standard difference-in-difference approach. Results show that unarmed private security patrolling decreases crime in the treated area by 30-43%. Our results suggest that a large share of the police-crime elasticity estimated by prior work is due to perceptual deterrence.

Vulnerability and resilience in the local systems: The case of Italian provinces

The aim of this work is to verify a theoretical representation of the multidimensional concept of territorial risk, through a study of Italian provinces. The concept is referred to the exposure of the territorial system to the risk of an exogenous event, as a combination of factors of fragility and resilience. In the proposed framework, elements of the organization of a territorial system had been identified, in its economic, social and environmental dimensions, mostly affecting his exposure to the adverse impact generated by a disturbing event and the ability to answer and to regenerate. According to this scheme of representation, the territorial risk is the result of the combination of these factors that influence the probability of a local system to undergo negative changes as a result of the occurrence of the event. The evaluation of vulnerability and resilience of a system, by adopting a holistic reading of the phenomenon, involves the identification of systemic components and attributes such as openness to the external environment, structural diversification, availability of resources, structural dependence/independence, functional redundancy, adaptability strategy. In the paper the authors propose the construction of an indicator system and composite indices for monitoring, through multivariate statistical techniques, the factors of fragility and ability to recovery. The proposed system is applied to a study of the economic, social and environmental vulnerability and resilience of the Italian provinces.

Springs and their offspring: the international consequences of domestic uprisings

AbstractA politicalspringis an abrupt, broad, sustained increase in public dissent in a state that has prohibited it, as in Czechoslovakia in 1968 or Tunisia in early 2011. Some springs produce offspring – clusters of events within neighbouring states (civic unrest, increased state repression, co-option of dissent, revolution) and among those states (intensification of international rivalries, foreign interventions). An English Spring in 1558–9 produced such a cluster in Northwestern Europe. This article addresses the underlying causal mechanism connecting springs and their offspring, rather than the related correlational question (viz. under what conditions a spring is followed by offspring). That mechanism istransnational group polarisation, or the progressive separation of preferences across a population into pro- and anti-government groups. Transnational polarisation along a pro-versus-anti-government axis is an endogenous process triggered by exogenous events, such as violence or public demonstrations that raise the status of, or threat to, one of the groups. It presents powerful actors across states with new threats and opportunities and can help explain how the Tunisian Spring of early 2011 produced throughout the Arab Middle East infectious unrest, serial repressions and reforms, heightened international tensions, and foreign interventions.

Macroprudential Policy and Credit Supply

Summary In this paper we analyze financial crises and the interactions of macroprudential policy and credit. Financial crises are recurrent systemic phenomena, often triggering deep and long-lasting recessions with large reductions in aggregate welfare, output and employment Importantly for policy, systemic financial crises are typically not random events triggered by exogenous events, but they tend to occur after periods of rapid, strong credit growth. Moreover, a credit crunch tends to follow in a financial crisis with negative aggregate real effects Macroprudential policy softens the credit supply cycles, with important positive effects on the aggregate real economy in crisis times.

Excess employment, media coverage and corporate valuation: Labour Contract Law in China

Previous research has found that firms’ excess employment will reduce corporate valuation as well as lead to a series of negative economic consequences. However, these studies cannot explain why the excess employment would lead to a series of negative economic consequences. Using the exogenous event of the promulgation of the new Labour Contract Law (‘the Act’) enacted in 2007 in China, this paper finds that an increase in excess employment will reduce the valuation of firms. With the promulgation and implementation of the Labour Contract Law, the negative correlation between excess employment and corporate valuation is significantly strengthened, which shows that excess employment has a more serious negative economic impact after the law is implemented. It has been shown elsewhere that labour costs have increased since the implementation of the Act. This paper reveals that the mechanism relating excess employment to negative economic consequences is that excess employment leads to increasing labour costs rather than reducing enterprise productivity. Furthermore, we present evidence that media coverage significantly reduces the negative correlation between excess employment and the valuation of the firm, which extends the information intermediary theory of media.

Information Shares in a Two-Tier FX Market

Using several popular measures of information share, we examine price discovery across the inter-dealer and dealer-customer market tiers in the foreign exchange market. We generally find that the information share of the inter-dealer tier is higher than that of the dealer-customer one for non-financial sector trades and is lower than the dealer-customer tier for financial sector trades. In the forward market, we find that the dealer-customer tier generally has the greater information share. Our results indicate the market where customers' trades are the most informative and how exogenous events can affect price discovery across markets and market tiers.

Economic Freedom and Financial Market Liquidity: Evidence from ADRs

This paper analyzes the effect of economic freedom on the liquidity of financial markets using a non-traditional approach. Using a sample of 393 American Depositary Receipts (ADRs), we examine the liquidity of these securities while conditioning on the level of economic freedom in the ADR home country. We find robust evidence that ADRs from countries with the most economic freedom have the most liquidity (i.e. the lowest bid-ask spreads and the least price impact). These findings are driven by certain characteristics of economic freedom, such as the lower levels of regulation, more free trade, stronger property-right protection, and sound money. In other tests, we examine liquidity surrounding the beginning of several broad-based regulatory changes in the Chinese financial system, which allowed for more open foreign investment and lending services. Using this (arguably) exogenous event as a natural experiment, we find meaningful improvements in the liquidity of Chinese ADRs vis-a-vis non-Chinese ADRs. These results suggest that causation flows from economic freedom to market liquidity instead of the other way around.

Assessing the potential impact of the Marikana incident on South African mining companies: An event method study

This study examines the potential impact of industrial unrest and the outbreak of violence at Marikana on 16 August 2012 on the share prices of mining companies listed on the Johannesburg Stock Exchange (JSE) using an event methodology. Contrary to expectations, the Marikana incident does not appear to have had a widespread and prolonged effect on the South African mining sector. This may be the result of the strike action already having been discounted into the price of mining shares, implying that the market was only reacting to the unusually violent (but short-lived) protest. Alternately, the results could be indicative of investor confidence in the corporate social responsibility initiatives of the South African mining industry as a whole. This paper is the first to examine the potential impact of the Marikana incident on the share prices of mining companies listed on the JSE. It should be of interest to both academics and practitioners wanting to understand how share prices react to exogenous events. It is also relevant for corporate-governance researchers concerned with the relevance of social and governance practices in a South African setting. This research is faced with the limitations associated with most statistical research: that causality cannot be ascribed to tested relationships. Notwithstanding these limitations, it is argued that these findings are important, given the significant coverage of the Marikana incident and the ongoing debate on the need for corporate social responsibility.

DNA Repair.

DNA is constantly damaged by various endogenous and exogenous events. Repair systems constantly scan the genome for DNA lesions and replace damaged and mismatched bases, which finally enables the complex DNA double strand to store genetic information. This year's Nobel Prize in Chemistry was awarded to pioneers in this field, T. Lindahl, P. Modrich, and A. Sancar.

Ingratiation and popularity as antecedents of justice: A social exchange and social capital perspective

We contribute to an emerging literature viewing organizational justice as an endogenous outcome that employees may attempt to proactively influence instead of an exogenous event to which employees react. Drawing on social capital and social exchange theory, we test a model whereby employees’ ingratiation toward their supervisor leads to higher levels of justice as a result of higher leader–member exchange (LMX) quality. We further identify employee’s popularity as a boundary condition, such that popular employees do not benefit from ingratiation in terms of LMX quality. Across three studies utilizing a variety of methodological designs, assessing constructs from different sources, and taking place in both controlled experimental settings as well as field settings, we largely find consistent results for our hypotheses. Overall, our findings extend theory on organizational justice by illuminating the role that employees’ volitional behavior, as well as the social context surrounding that behavior, play in influencing justice.

Interview with David E. Smith

David E. Smith is a senior Researcher in the Intelligent Systems Division at NASA Ames Research Center. He received his Ph.D. in 1985 from Stanford University, and spent time as a Research Associate at Stanford, a Scientist at the Rockwell Palo Alto Science Center, and a Visiting Scholar at the University of Washington before joining NASA in 1997. Beginning in 1999, he served as the lead of the 18 member planning and scheduling group at NASA Ames for 6 years before abdicating to devote more time to research. Much of his research has focused on pushing the boundaries of AI planning technology to handle richer models of time, concurrency, exogenous events, uncertainty, and oversubscription. Smith served as an Associate Editor for the Journal of Artificial Intelligence Research (JAIR) from 2001–2004, and as Guest Editor for the JAIR Special Issue and Special Track on the 3rd and 4th International Planning Competitions. He served on the JAIR Advisory Board 2004–2007. Smith was recognized as a AAAI Fellow in 2005, and served on the AAAI Executive Council 2007–2010. KI Would you like to tell us about your journey to NASA and your personal motivation for this?

Hierarchy aware distributed plan execution monitoring

Collaborative plan execution is becoming increasingly important given its potential for operational agility and cost reduction. In this paper we propose a distributed and hierarchy aware monitoring procedure for operational plan execution taking place in a dynamic environment characterized by unreliable communication and exogenous events. The contribution of this paper consists in employing a hierarchical clustering approach supporting a multi-party and hierarchy aware information sharing mechanism that is resilient to disruptions in the execution environment. The proposed distributed monitoring procedure uses asymmetric clustering to reflect hierarchical relationships along with gossip based communication across the clusters. Of significance is the information sharing mechanism formalization which utilizes a fresh information window in conjunction with communicating Markov Decision Processes. We show the usefulness of assessing shared information awareness via probabilistic model checking for various combinations of clustering topology and disruption conditions. In this context, we assess formal specifications expressed in probabilistic temporal logic and show how the model checking results can be used to derive the best fresh window value to maximize an information awareness utility function. An illustrative case study is also presented.

Connecting within and between-hosts dynamics in the influenza infection-staged epidemiological models with behavior change

Influenza viruses are a major public health problem worldwide. Although influenza has been extensively researched, there are still many aspects that are not fully understood such as the effects of within and between-hosts dynamics and their impact on behavior change. Here, we develop mathematical models with multiple infection stages and estimate parameters based on within-host data to investigate the impact of behavior change on influenza dynamics. We divide the infected population into three and four groups based on the age of the infection, which corresponds to viral load shedding. We consider within-host data on viral shedding to estimate the length and force of infection of the different infectivity stages. Our results show that behavior changes, due to exogenous events (e.g., media coverage) and disease symptoms, are effective in delaying and lowering an epidemic peak. We show that the dynamics of viral shedding and symptoms, during the infection, are key features when considering epidemic prevention strategies. This study improves our understanding of the spread of influenza virus infection in the population and provides information about the impact of emergent behavior and its connection to the within and between-hosts dynamics.

TACC3 in personalized medicine.

Cells are constantly exposed to endogenous and exogenous DNA damage events. In order to confront DNA damage and to maintain genomic integrity, cells have evolved a fine-tuned network of cellular pathways, collectively known as the DNA damage response (DDR). The broad components of DDR include surveillance mechanisms, cell cycle checkpoints, DNA repair pathways, and apoptotic programs. Interestingly, the very deficiencies in DDR that lead to cell death, genomic instability, and tumorigenesis, are also the very mechanisms that can be harnessed for cancer's own demise. Such vulnerabilities manifest as deregulated DDR-associated pathways that, with further elucidation, can become prognostic and predictive biomarkers and therapeutic targets in personalized cancer therapy. Transforming Acidic Coiled-Coil 3 (TACC3) is acknowledged for its canonical role in centrosome-microtubule spindle dynamics, and its deregulation has been linked to a variety of human cancers, including breast, colon, liver and lung cancers [1]. Also, high TACC3 has been shown to be strongly associated with poor survival in breast and lung cancer patients [1]. Interestingly, p53-deficient mouse with conditional knockout of Tacc3 showed a remarkable thymus lymphoma regression [2]. Given these associations, it is imperative to clarify the precise mechanistic contribution of TACC3 to tumorigenesis and cancer development. Previously, we demonstrated that TACC3 plays a pivotal role in the process of epithelial-mesenchymal transition (EMT), a key step of tumor progression and metastasis, by promoting phosphoinositide 3-kinase (PI3K)/Akt and extracellular signaling related kinase (ERK) signaling [3]. In our most recent study, we found that high TACC3 induces spontaneous DNA damage and impairs G2/M checkpoint function and repair of DSBs (both homologous recombination [HR] and non-homologous end joining [NHEJ]), thus increasing the frequency of chromosomal aberrations, at least in part, by TACC3-mediated negative regulation of Ataxia telangiectasia mutated (ATM) [1]. Given TACC3's emerging role in DDR regulation, we then sought to investigate TACC3's predictive value for hypersensitivity to radiation and poly(ADPribose)polymerase (PARP) inhibitor treatment. Unsurprisingly, high TACC3 levels confer cellular hypersensitivity to radiation and the PARP inhibitors Olaparib (AZD2281) and NU1025 [1]. In spite of the emerging link between high TACC3 and impaired DDR, unanswered questions need to be uncovered to have a complete knowledge of TACC3 functionality in human cancer. For example, the fact that re-expression of ATM did not completely rescue high TACC3-mediated DNA damage, suggests that there are other mechanisms unaccounted for that might contribute to TACC3-mediated genomic instability. Since Aurora Kinase A (AurA) acts as an upstream of TACC3 [4], and because both TACC3 and Aurora Kinase A disrupt normal cellular response to DNA damage, although TACC3 affects both Chk1 and Chk2 [1] while AurA only affects Chk1 [5], it would be interesting to clarify whether TACC3-mediated disruption of DDR occurs in an AurA-dependent manner. Additionally, a more robust understanding of the upstream regulation of TACC3 is required; this may shed light on the etiology of TACC3 upregulation in various cancers, and provide a starting point for thinking about cancer prevention. Meanwhile, since TACC3 is actually downregulated in a certain subset of cancers [6], it remains unclear if TACC3 is a tumor suppressor, an oncogene, or both. In any case, it is clear that TACC3 deregulation is associated with cancer. While knowledge gaps of TACC3's role in cancer still remain, the clinical-translational significance of TACC3 is becoming increasingly clear. The distribution of TACC3 at the interface of the mitotic spindle-assembling machinery, vital for tumor survival and progression, makes TACC3 a superior therapeutic target for anti-cancer drugs precisely designed to inhibit the mitotic spindle-microtubule of cancer with aberrant TACC3, without interfering with the microtubules activity in non-dividing cell. Furthermore, we discovered that depletion of TACC3 renders cancer cells more sensitive to the anti-microtubule agent paclitaxel [7], a phenomenon consistent with the findings of Schmidt et al. [8]. Taken together, we speculate that patients with high levels of TACC3 may benefit more from radiotherapy, PARP inhibitor therapy, or a combination of both than those with comparatively lower levels of TACC3. On the other hand, patients with low levels of TACC3 may have a better response to paclitaxel. In addition to opening up new avenues for patient stratification, TACC3 also harbors prognostic potential, especially in light of aforementioned evidence of TACC3's role in EMT. Thus, tracking the status of TACC3 levels may also offer an opportunity for monitoring tumor progression and metastasis. As the emerging importance of TACC3 for cancer is increasingly apparent, we are better positioned to strategically address knowledge gaps in cancer etiology, and more effectively reap the harvest of personalized cancer therapy.