Critical Market Crashes

This review is a partial synthesis of the book ``Why stock market crash'' (Princeton University Press, January 2003), which presents a general theory of financial crashes and of stock market instabilities that his co-workers and the author have developed over the past seven years. The study of the frequency distribution of drawdowns, or runs of successive losses shows that large financial crashes are ``outliers'': they form a class of their own as can be seen from their statistical signatures. If large financial crashes are ``outliers'', they are special and thus require a special explanation, a specific model, a theory of their own. In addition, their special properties may perhaps be used for their prediction. The main mechanisms leading to positive feedbacks, i.e., self-reinforcement, such as imitative behavior and herding between investors are reviewed with many references provided to the relevant literature outside the confine of Physics. Positive feedbacks provide the fuel for the development of speculative bubbles, preparing the instability for a major crash. We demonstrate several detailed mathematical models of speculative bubbles and crashes. The most important message is the discovery of robust and universal signatures of the approach to crashes. These precursory patterns have been documented for essentially all crashes on developed as well as emergent stock markets, on currency markets, on company stocks, and so on. The concept of an ``anti-bubble'' is also summarized, with two forward predictions on the Japanese stock market starting in 1999 and on the USA stock market still running. We conclude by presenting our view of the organization of financial markets.Comment: Latex 89 pages and 38 figures, in press in Physics Report

Community Time-Activity Trajectory Modelling based on Markov Chain Simulation and Dirichlet Regression

Accurate modeling of human time-activity trajectory is essential to support community resilience and emergency response strategies such as daily energy planning and urban seismic vulnerability assessment. However, existing modeling of time-activity trajectory is only driven by socio-demographic information with identical activity trajectories shared among the same group of people and neglects the influence of the environment. To further improve human time-activity trajectory modeling, this paper constructs community time-activity trajectory and analyzes how social-demographic and built environment influence people s activity trajectory based on Markov Chains and Dirichlet Regression. We use the New York area as a case study and gather data from American Time Use Survey, Policy Map, and the New York City Energy & Water Performance Map to evaluate the proposed method. To validate the regression model, Box s M Test and T-test are performed with 80% data training the model and the left 20% as the test sample. The modeling results align well with the actual human behavior trajectories, demonstrating the effectiveness of the proposed method. It also shows that both social-demographic and built environment factors will significantly impact a community's time-activity trajectory. Specifically, 1) Diversity and median age both have a significant influence on the proportion of time people assign to education activity. 2) Transportation condition affects people s activity trajectory in the way that longer commute time decreases the proportion of biological activity (eg. sleeping and eating) and increases people s working time. 3) Residential density affects almost all activities with a significant p-value for all biological needs, household management, working, education, and personal preference.Comment: to be published in Computers, Environment and Urban Syste

Individual personality differences in adjustment to retirement

Includes bibliographical references.2015 Summer.Retirement is an important life event to study at present, because more people are entering their retirement years and are spending more time in retirement than ever before in our nation’s history. Historically, research has shown mixed results on effects of retirement that are not accurately explained by any one theory. These mixed results suggest the possibility of individual differences in retirement adjustment that may not be accounted for with aggregated data. Wang, Henkens, and Shultz (2011) proposed a comprehensive framework of retirement adjustment: the resource-based dynamic perspective, which reasons that adjustment is influenced by antecedent variables, via level of resources possessed by the individual at a given time. The current study seeks to assess the relation between personality as an antecedent variable and retirement adjustment in a longitudinal analysis of participants from the nationally representative Health and Retirement Study. Resources are also modeled as covariates in the analysis. Results should be interpreted with caution due to limitations in model fit. Results from the Growth Mixture Model (GMM) revealed two classes of retirement trajectories and certain personality traits were significant as predictors for these trajectories. Implications for both research and practice are discussed

Urban Street Networks and Sustainable Transportation

Urban street space is challenged with a variety of emerging usages and users, such as various vehicles with different speeds, passenger pick-up and drop-off by mobility services, increasing parking demand for a variety of private and shared vehicles, new powertrains (e.g., charging units), and new vehicles and services fueled by digitalization and vehicle automation. These new usages compete with established functions of streets such as providing space for mobility, social interactions, and cultural and recreational activities. The combination of these functions makes streets focal points of communities that do not only fulfill a functional role but also provide identity to cities. Streets are prominent parts of cities and are essential to sustainable transport plans. The main aim of the Street Networks and Sustainable Transportation collection is to focus on urban street networks and their effects on sustainable transportation. Accordingly, various street elements related to mobility, public transport, parking, design, and movement of people and goods at the street level can be included

Processes of long-term work disability and socioeconomic disparities : unwinding the roles of family background, sickness absence, and psychosocial work environment

Due to population ageing and the increasing dependency ratio, maintaining a sufficient workforce has become an important national policy target in Finland. As the population shrinks, prolonging working careers becomes one of the key factors in sustaining a sufficient workforce. Work disability, especially when it is long-term, is one of the main reasons for leaving the labour market early. Previous studies have identified many risk factors associated with long-term work disability, of which one of the most important is low socioeconomic status. However, to date very little research has been conducted on the mechanisms underlying the risk of long-term work disability and the associated socioeconomic disparities. This study examines the process leading to the development of a long-term work disability, and the socioeconomic differences in this process. This dissertation consists of four studies that examine two aspects of long-term work disability: the transition to sickness absence and disability retirement. Further, they examine the socioeconomic disparities that relate to these transitions arising from family background, sickness absence development and psychosocial work environment. The studies use longitudinal register-based datasets on the Finnish or Swedish population over a fifteen years period from 1999–2014, with national representative samples. The first article is based on a 10 % population sample of Finnish residents and uses a discrete-time event history model to examine the association between educational attainment and family background on disability retirement in young adulthood. The second and third articles use a 70 % population sample of Finnish residents linked to data on sickness benefits and disability retirement. These articles use a Cox proportional hazards model to study the role of sickness absence length and diagnosis as predictors of disability retirement in different occupational classes among women and men. The fourth article is based on a full population data of Swedish residents linked with data from labour market surveys and sickness insurance. The article examines the relationship between psychosocial work environment, or more precisely, the occupation-specific job demands and job control in occupations, and the risk of accumulating of sickness absence and disability pension days over time using group-based trajectory analysis and multinomial regression analysis. The results of these articles demonstrate that the risk factors of long-term work disability and the associated socioeconomic disparities are associated with the family background and they are observed at an early phase during the life-course. Low level of education and low levels of parental education and income were associated with young adults’ disability retirement. In particular, young adults whose parents have a tertiary education and who themselves have only a basic education are at a greatest risk of disability retirement. This result indicate that parents with higher education can be more able to assist their offspring in getting help for their work disability. Later in working life, sickness absence is another important factor in which the development of long-term work disability and the associated socioeconomic disparities develop. Long-term unemployed and manual workers have the highest risk of disability retirement, and non-manual employees have the lowest risk. However, the accumulation of sickness absence days increases the risk of disability retirement most strongly among non-manual employees, and the least among manual workers. In particular, long-term sickness absence due to mental and behavioural disorders or musculoskeletal diseases is linked to all-cause disability retirement and disability retirement due to same diagnostic group. Further analysis on the diagnoses revealed that while sickness absence due to respiratory diseases or circulatory diseases were the strongest predictors of disability retirement due to some other diagnostic group. The role of diagnosis in the transition from sickness absence to disability retirement was similar across occupational classes. Analysing the effect of a psychosocial work environment revealed that occupations with low levels of job demands or low job control, and especially with a combination of these, are associated with unfavourable accumulation of sickness absence and disability pension days. Contrarily, occupations with high levels of job demands and job control are associated with low accumulation of sickness absence and disability pension days. To conclude, risks of developing a long-term work disability can be identified at different processes in childhood and in work life. Attention should be paid to prevent work disability at an early stage of life. Especially disadvantaged families should be helped by providing low-threshold services to ensure that health problems leading to work disability are identified as early as possible. Work disability can be prevented by intervening, for example, in the accumulation of sickness absence days and in the work environment. In addition, providing equal access to care, low-threshold services and modifying work environment according to individual’s work ability can help prevent the onset and development of long-term work disability, improve wellbeing at work and prolong working careers. Measures should be tailored according to one’s socioeconomic position, as the development of long-term work disability varies between occupations. Understanding the risk factors associated with longterm work disability not only helps to prevent long-term work disability at the population level, but also helps to target preventive actions more effectively at those who need it, reducing social inequalities in well-being at work and in health.Väestön ikääntymisen ja huoltosuhteen heikentymisen vuoksi riittävän työvoiman ylläpitämisestä on tullut tärkeä tavoite suomalaisessa politiikassa. Väestönkasvun hidastuessa on työurien pidentäminen yksi tärkeimmistä keinoista riittävän työvoiman ylläpitämiseksi. Etenkin pitkittynyt työkyvyttömyys on yksi keskeisimmistä syistä ennenaikaiseen työelämästä poistumiseen. Aikaisemmat tutkimukset ovat tunnistaneet monia pitkittyneeseen työkyvyttömyyteen liittyviä riskitekijöitä, joista yksi tärkeimmistä on matala sosioekonominen asema. Pitkittyneen työkyvyttömyyden riskin ja siihen liittyvien sosioekonomisten erojen taustalla olevia mekanismeja on toistaiseksi tutkittu melko vähän. Tämän tutkimuksen tavoitteena on selvittää pitkäaikaisen työkyvyttömyyden kehitysprosesseja sekä siinä ilmeneviä sosioekonomisia eroja. Väitöskirja koostuu neljästä osatutkimuksesta. Osatutkimukset käsittelevät sairauspäivärahakaudelle ja työkyvyttömyyseläkkeelle siirtymistä sekä niihin liittyviä sosioekonomisia eroja perhetaustan, sairauspäivärahahistorian ja psykososiaalisen työympäristön näkökulmista. Tutkimuksessa käytetään pitkittäisiä rekisteriaineistoja suomalaisesta ja ruotsalaisesta työikäisestä väestöstä ajanjaksolla 1999– 2014. Ensimmäisen artikkelin aineisto pohjautuu 10 % satunnaisotokseen suomalaisista. Artikkelissa tutkitaan diskreetin elinaikamallin avulla perhetaustan ja kouluttautumisen yhteyttä nuorten aikuisten työkyvyttömyyseläkkeelle siirtymiseen. Toisessa ja kolmannessa artikkelissa käytetään 70 % satunnaisotosta työikäisistä suomalaisista, yhdistettynä sairauspäiväraha- ja työkyvyttömyystietoihin. Näissä artikkeleissa tarkastellaan Coxin suhteellisten hasardien mallin avulla sairauspäivärahan pituuden ja diagnoosin roolia työkyvyttömyyseläkettä ennustavana tekijänä eri ammattiasemissa olevilla naisilla ja miehillä. Neljännessä artikkelissa käytetään ruotsalaista väestöaineistoa yhdistettynä sairausvakuutustietoihin ja työelämätutkimuksissa kerättyihin aineistoihin. Artikkelissa tutkitaan kehityspolkuanalyysin ja multinominaalisen regressioanalyysin avulla psykososiaalisen työympäristön yhteyttä sairauspäiväraha- ja työkyvyttömyyseläkepäivien kertymiseen pitkällä aikavälillä naisilla ja miehillä. Ensimmäisen artikkelin tulokset osoittavat, että pitkittyneen työkyvyttömyyden riskitekijät ja siihen liittyvän sosioekonomiset erot ovat yhteydessä perhetaustaan ja ne ovat havaittavissa jo varhaisessa elämänvaiheessa. Vanhempien matala koulutus ja matalat tulot, sekä nuoren oma matala koulutus ovat yhteydessä nuoren aikuisen työkyvyttömyyseläkkeelle siirtymiseen. Erityisesti nuoret aikuiset, joiden vanhemmilla on korkea-asteen koulutus ja itsellään perusasteen koulutus, ovat suurimmassa riskissä siirtyä työkyvyttömyyseläkkeelle. Myöhemmin työelämässä sairauspäivärahakausi on toinen tärkeä nivelvaihe, jossa pitkittyneen työkyvyttömyyden kehitys ja siihen liittyvät sosioekonomiset erot kehittyvät. Pitkäaikaistyöttömillä ja työntekijäammateissa työskentelevillä on korkein ja ylemmillä toimihenkilöillä kaikkein matalin riski siirtyä työkyvyttömyyseläkkeelle. Kertyvät sairauspäivärahapäivät kuitenkin kasvattavat työkyvyttömyyseläkkeelle siirtymisen riskiä kaikkein voimakkaimmin ylemmillä toimihenkilöillä, ja hitaimmin työntekijäammatissa työskentelevillä. Erityisesti pitkittynyt mielenterveyden ja käyttäytymisen häiriöiden tai tuki- ja liikuntaelinsairauksien perusteella myönnetty sairauspäiväraha on vahvasti yhteydessä työkyvyttömyyseläkkeelle siirtymiseen mistä tahansa tai samasta diagnoosista. Lisäanalyysit osoittavat, että sairauspäiväraha hengityselinten tai verenkiertoelinsairauksien diagnoosilla ennustivat ennen kaikkea työkyvyttömyyseläkettä jollain muulla diagnoosilla. Diagnoosin rooli sairauspäivärahalta työkyvyttömyyseläkkeelle siirryttäessä oli melko samankaltainen eri ammattiryhmissä. Työympäristön näkökulmasta ammatit, joissa on matala työn vaatimustaso ja matala vaikutusmahdollisuuksien taso, tai joissa nämä molemmat yhdistyvät, ovat yhteydessä epäedulliseen sairauspäiväraha- ja työkyvyttömyyseläkepäivien kertymiseen. Näiden matalaan kertymiseen ovat yhteydessä sen sijaan ammatit, joissa työn vaatimus- ja vaikuttamismahdollisuudet ovat korkeita. Yhteenvetona voidaan todeta, että pitkittyneen työkyvyttömyyden riski on tunnistettavissa erilaisissa prosesseissa sekä lapsuudessa, että työelämässä. Työkyvyttömyyden ehkäisemiseen tulisikin kiinnittää huomiota jo varhaisessa elämänvaiheessa. Erityisesti vähäosaisemmille perheille olisi tarjottava matalan kynnyksen palveluita, jotta työkyvyttömyyteen johtaviin terveysongelmiin voitaisiin tarttua mahdollisimman varhain. Pitkittynyttä työkyvyttömyyttä voidaan ehkäistä myös myöhemmin työelämässä puuttumalla esimerkiksi sairauspoissaolopäivien kertymiseen ja psykososiaaliseen työympäristöön. Yhdenvertainen hoitoon pääsy, matalan kynnyksen palvelujen tarjoaminen ja työympäristön muuttaminen yksilöllisen työkyvyn mukaan voi auttaa estämään pitkäaikaisen työkyvyttömyyden syntymistä, parantamaan työhyvinvointia ja pidentämään työuraa. Kaikki nämä toimenpiteet tulisi räätälöidä ammattiryhmän mukaan, sillä pitkäaikaisen työkyvyttömyyden kehitys vaihtelee niiden välillä. Ymmärtämällä pitkittyneeseen työkyvyttömyyteen liittyviä riskitekijöitä voidaan sekä ehkäistä työkyvyttömyyttä väestötasolla, että kohdentaa ennaltaehkäiseviä toimia yhä tehokkaammin niitä tarvitseville, kaventaen työhyvinvointiin ja terveyteen liittyvää sosiaalista eriarvoisuutta

Water Security Issues Affecting Migration and Conflict in the Middle East

Iran is facing a daunting reality regarding the future of their water resources which may result in conflict and migration within the country with the potential to affect the Middle East and North African region and beyond. The country has failed to address critical preservation, risk mitigation, infrastructural, and political efforts to accommodate their rising population due to economic expansion. Water resources are dependent on social, political, economic, and environmental variables related to conflict and migration. Given the recent examples of water security issues in Syria resulting in migration and conflict, this thesis investigates the total available water per capita as a driver for the potential collapse of Iran’s water resources. Portions of two key world system dynamics models were combined to identify interrelated variables leading to migration and conflict. It was found through multiple simulations that decreasing water per capita levels leads to increases in aggregated migration and death rates for this particular investigation. Further experimentation with other interrelated variables such as civil liberties, level of government, and GDP per capita may highlight other drivers and allow extension of this model to other countries of interest

The American Academy of Health Behavior 2020 Annual Scientific Meeting: Transforming the narrative to meet emerging health behavior challenges

The American Academy of Health Behavior (AAHB) anticipated hosting it\u27s 20th Annual Scientific Meeting at the Embassy Suites by Hilton in Napa Valley, CA June 28-July 1, 2020. The meeting\u27s theme was Transforming the narrative to meet emerging health behavior challenges. This publication includes the refereed abstracts that were accepted for presentation at the 2020 Annual Scientific Meeting, prior to the meeting\u27s cancellation

Dev Psychopathol

Although there is strong evidence supporting the association between childhood adversity and symptomatology during adolescence, the extent to which adolescents present with distinct patterns of co-occurring post-traumatic stress (PTS) and externalizing symptoms remains unclear. Additionally, prior research suggests that experiencing nonviolent, negative life events may be more salient risk factors for developing some forms of psychopathology than exposure to violence. The current study used latent profile analysis to identify subgroups of early adolescents with distinct patterns of PTS, physical aggression, delinquency, and substance use, and examined subgroup differences in exposure to three forms of violent and nonviolent childhood adversity. Participants were a predominantly low-income, African American sample of 2,722 urban middle school students (M age = 12.9, 51% female). We identified four symptom profiles: low symptoms (83%), some externalizing (8%), high PTS (6%), and co-occurring PTS and externalizing symptoms (3%). A higher frequency of witnessing violence was associated with increased odds of membership in subgroups with externalizing symptoms, whereas a higher frequency of nonviolent, negative life events was associated with increased odds of membership in subgroups with PTS symptoms. Interventions aimed to address childhood adversity may be most effective when modules addressing both PTS and externalizing symptoms are incorporated.R01 HD089994/HD/NICHD NIH HHSUnited States/T32 DA043449/DA/NIDA NIH HHSUnited States/U01 CE001956/CE/NCIPC CDC HHSUnited States/2023-06-20T00:00:00Z34924089PMC920716011624vault:4287