Contemporaneous Changes Research Articles

The Effect of Volatility Expectations on Large Stock Price Changes

<p><em>My study explores the effect of future volatility expectations, embedded in VIX index, on large daily stock price changes and on subsequent stock returns. Following both psychological and financial literature claiming that good (bad) mood may cause people to perceive positive (negative) future outcomes as more probable and that the changes in the value of VIX may be negatively correlated with contemporaneous investors’ mood, I hypothesize that if a major positive (negative) stock price move takes place on a day when the value of VIX falls (rises), then its magnitude may be amplified by positive (negative) investors’ mood, creating price overreaction to the initial company-specific shock, which may result in subsequent price reversal. In line with my hypothesis, I document that both positive and negative large price moves accompanied by the opposite-sign contemporaneous changes in VIX are followed by significant reversals on the next two trading days and over five- and twenty-day intervals following the event, the magnitude of the reversals increasing over longer post-event windows, while large stock price changes taking place on the days when the value of VIX moves in the same direction are followed by non-significant price drifts. The results remain robust after accounting for additional company (size, beta, historical volatility) and event-specific (stock’s return and trading volume on the event day) factors, and are stronger for small and volatile stocks.</em></p>

The Effect of Volatility Expectations on Large Stock Price Changes

<p><em>My study explores the effect of future volatility expectations, embedded in VIX index, on large daily stock price changes and on subsequent stock returns. Following both psychological and financial literature claiming that good (bad) mood may cause people to perceive positive (negative) future outcomes as more probable and that the changes in the value of VIX may be negatively correlated with contemporaneous investors’ mood, I hypothesize that if a major positive (negative) stock price move takes place on a day when the value of VIX falls (rises), then its magnitude may be amplified by positive (negative) investors’ mood, creating price overreaction to the initial company-specific shock, which may result in subsequent price reversal. In line with my hypothesis, I document that both positive and negative large price moves accompanied by the opposite-sign contemporaneous changes in VIX are followed by significant reversals on the next two trading days and over five- and twenty-day intervals following the event, the magnitude of the reversals increasing over longer post-event windows, while large stock price changes taking place on the days when the value of VIX moves in the same direction are followed by non-significant price drifts. The results remain robust after accounting for additional company (size, beta, historical volatility) and event-specific (stock’s return and trading volume on the event day) factors, and are stronger for small and volatile stocks.</em></p>

Participation in Mammography Screening Accomplishes an Enduring and Significant Reduction in Breast Cancer Mortality in the Era of Modern Therapy: An Observational Study Spanning 52 Years

Background: A significant decrease in breast cancer mortality has been demonstrated in populations invited to mammography screening. There have been questions regarding the value of mammography in the era of modern therapies, and the relative contribution of mammography screening and modern therapy on mortality reduction. Aim: We have sought to clarify the extent to which early detection through mammography screening contributes to the reduction of breast cancer death in the era of modern adjuvant therapies. We address this question by studying five decades of continuous data from a stable population spanning the pre- and postscreening and adjuvant therapy periods. Methods: We analyzed changes in breast cancer mortality in a stable population in Dalarna County, Sweden, among women aged 40-69 years during the 52 years from 1964 through 2015. Mortality data were obtained from the National Cause of Death Register in Sweden, and incidence data from the Swedish National Cancer Registry. Crude and incidence-based mortality rates were compared among four successive 13-year periods: the prescreening period from 1964 through 1976, the Swedish Two-County randomized screening trial period from 1977 through 1989, and two service screening periods from 1990-2002 and from 2003-2015. Furthermore, we measured the effect of early detection upon breast cancer mortality in women exposed to mammography screening by comparison with breast cancer death in women not exposed to mammography screening, within these three screening periods. Data were analyzed by Poisson regression, with corrections for lead time and self-selection bias. Results: There were 5844 incident cases and 1425 breast cancer deaths during the 52 years of observation. The relative breast cancer mortality rates associated with exposure to screening, adjusted for self-selection bias, were 0.46 (95% CI 0.30-0.69) in the trial period (1977-1989), 0.44 (95% CI 0.30-0.65) in the 1990-2002 period, and 0.37 (95% CI 0.24-0.56) in the 2003-2015 period. The significant reductions in incidence-based breast cancer mortality associated with exposure to screening were independent of contemporaneous changes in therapy. Conclusion: The combination of early detection of breast cancer through mammography screening and the resultant earlier treatment has significantly reduced breast cancer mortality in Dalarna County in the women exposed to screening, compared with the women not participating in screening, by a factor of 2.2 in the screening trial period, increasing to a factor of 2.7 in the most recent service screening period. These mortality benefits can be attributed to the far greater effectiveness of modern therapeutic methods upon cancers detected at screening compared with the poorer effectiveness of the same therapeutic methods in women not participating in screening.

Exploring Drivers of Regional Water‐Quality Change Using Differential Spatially Referenced Regression—A Pilot Study in the Chesapeake Bay Watershed

AbstractAn understanding of riverine water‐quality dynamics in regional mixed‐land use watersheds is the foundation for advances in landscape biogeochemistry and informed land management. A differential implementation of the statistical/process‐based model SPAtially Referenced Regressions on Watershed attributes (SPARROW; Smith et al., https://doi.org/10.1029/97wr02171) is proposed to empirically relate a regional pattern of changes in flow‐normalized constituent flux, over a multiyear period, to contemporaneous changes in spatially referenced explanatory variables. In a pilot application, the differential model, called Spatiotemporal Watershed Accumulation of Net effects (SWAN), is used to explore factors influencing changes in flow‐normalized flux of total nitrogen over the period 1990–2010 at 43 sites in the nontidal Chesapeake Bay watershed. A seven‐parameter model explains 80% of the transformed variability in independently estimated flux changes, indicating that storage effects having characteristic time scales greater than 20 years had a small influence, relative to changes in inputs, on regional water‐quality response. Results suggest that 1990–2010 changes in total‐nitrogen flux are largely the outcome of increased nonpoint‐source pollution associated with urban and suburban development, modulated to the point of negation by terrestrial losses stemming from widespread increases in air temperature and precipitation. The loss mechanism is qualitatively consistent with denitrification; however, increases in aboveground biomass, agricultural nitrogen exports, or hydrologic flushing are also plausible contributors. Although qualified by a small sample size and constraints on explanatory data availability, the pilot suggests that SWAN is a promising approach for broadening scientific understanding of factors driving regional water‐quality change and for supporting evidence‐based land‐management decisions.

Ratooning as an adaptive management tool for climatic change in rice systems along a north-south transect in the southern Mississippi valley

The effect of climate change on recent and projected increases in surface temperatures is well-documented. For agriculture, such changes can impact crop phenology and production, but the degree of impact will depend, in part, on contemporaneous changes in crop management. In the current study, we quantified recent (last 40 years) and projected (to 2095) changes in air temperature and associated changes in growing season duration for rice along a latitudinal north-south gradient of the lower Mississippi valley. Recent and projected climate data indicated an ongoing increase in air temperature and growing season length with latitudes above ∼31 °N. We then applied the DD50 growing degree day model to these data to determine if ratooning, a management practice that produces a second rice harvest with minimal resource input, could be employed. The model results were analyzed and used relative to the southernmost location, Cameron Parish, where the season length and daily temperatures currently allow for ratooning to be a common practice for long-grain cultivars (e.g., Cocodrie, Catahoula). The recent and projected increases in temperature and seasonality indicate that ratooning could already be adopted in Avoyelles Parish, and is potentially possible as far north as Cape Girardeau County (37 °N) by the end of the 21 st century. While additional information regarding possible effects of heat stress, water availability, rising carbon dioxide (CO2) levels, and other factors will be necessary to fully assess ratooning potential, our research indicated that ongoing increases in temperature and season length may allow agronomic management practices, such as ratooning, to help adapt rice production to climatic uncertainty.

Covariation of Neonatal Intensive Care Unit-Level Patent Ductus Arteriosus Management and In-Neonatal Intensive Care Unit Outcomes Following Preterm Birth

To test the hypothesis that neonatal intensive care unit (NICU)-specific changes in patent ductus arteriosus (PDA) management are associated with changes in local outcomes in preterm infants. This retrospective repeated-measures study of aggregated data included infants born 400-1499 g admitted within 2 days of delivery to NICUs participating in the California Perinatal Quality Care Collaborative. The period 2008-2015 was divided into four 2-year epochs. For each epoch and NICU, we calculated proportions of infants receiving cyclooxygenase inhibitor (COXI) or PDA ligation and determined NICU-specific changes in these therapies between consecutive epochs. Generalized estimating equations were used to examine adjusted relationships between NICU-specific changes in PDA management and contemporaneous changes in local outcomes. We included 642 observations of interepoch change at 119 hospitals summarizing 32 094 infants. NICU-specific changes in COXI use and ligation showed significant dose-response associations with contemporaneous changes in adjusted local outcomes. Each percentage point decrease in NICU-specific proportion treated with either COXI or ligation was associated with a 0.21 percentage point contemporaneous increase in adjusted local in-hospital mortality (95% CI 0.06, 0.33; P = .005) among infants born 400-749 g. In contrast, decreasing NICU-specific ligation rate among infants 1000-1499 g was associated with decreasing adjusted local bronchopulmonary dysplasia (P = .009) and death or bronchopulmonary dysplasia (P = .01). NICU-specific outcomes of preterm birth co-vary with local PDA management. Treatment for PDA closure may benefit some infants born 400-749 g. Decreasing NICU-specific rates of COXI use or ligation were not associated with increases in local adjusted rates of examined adverse outcomes in larger preterm infants.

Being Right is Not Enough: Buying Options to Bet on Higher Realized Volatility

Speculators who wish to bet on higher future volatility often purchase options to “go long volatility.” Should investors who buy options expect to profit when realized volatility increases? If so, under what conditions? To answer these questions, we conduct an analysis of the relationship between long volatility performance (buying options) and contemporaneous changes in volatility. We find that buying one-month S&P 500 options is only consistently profitable in the highest decile of changes in one-month volatility. Buying options consistently loses money in the lowest seven deciles of changes in volatility. We then study the trade entry and exit timing required to retain the profits from long option positions during significant volatility increases. We find similar results between the S&P 500 options market and global equity option markets.

Multi-Level Order-Flow Imbalance in a Limit Order Book

We study the multi-level order-flow imbalance (MLOFI), which is a vector quantity that measures the net flow of buy and sell orders at different price levels in a limit order book (LOB). Using a recent, high-quality data set for six liquid stocks on Nasdaq, we fit a simple, linear relationship between MLOFI and the contemporaneous change in mid-price. For all six stocks that we study, we find that the out-of-sample goodness-of-fit of the relationship improves with each additional price level that we include in the MLOFI vector. Our results underline how order-flow activity deep into the LOB can influence the price-formation process.

Diachronic variation in secondary burial practices in Bronze and Iron Age Moravia

The transition from inhumation to cremation is a well-documented phenomenon in Bronze Age Central Europe. However, almost nothing is known about similar transitions taking place in other mortuary practices, such as secondary burials. This study brings new insights into diachronic trends in secondary burials during the Central European Bronze and Iron Age. Diachronic trends in secondary burials are defined here by different kinds of excarnation. The type of excarnation was observed in 23 secondary burials dating to the Early Bronze Age and the turn of the Late Bronze to Early Iron Age at five sites in Moravia (Czech Republic). Osteological and taphonomic assessment of unburned human bones recovered from settlement contexts indicates a changing pattern of secondary burial practice over time. Early Bronze Age human remains bear traces of both passive excarnation by natural agents, such as exposure to carnivores, and excarnation by primary burial. By the Late Bronze Age and Early Iron Age secondary burials show evidence of excarnation with tools. This modification of secondary burial practices, may be connected with a contemporaneous change of primary burial practices from inhumation to cremation.

Effect of Contemporaneous Exchange Rate Changes on Value of Multinational Nonfinancial Companies Listed at Nairobi Securities Exchange

The study investigates the effect of contemporaneous exchange rate changes on value of multinational nonfinancial companies listed at Nairobi Securities Exchange for period 2001-2016. Unexpected exchange rate changes and lagged exchange rate movements were used as control variables. The study adopted a two staged methodology. The first stage involved the determination of the foreign exchange exposure. At this point the REER is determined as the weighted average of the seven major currencies used by Kenya. The unexpected foreign exchange changes were determined using the ARIMA and GARCH model. The second stage of analysis involves a panel model where different aspects of foreign exchange exposure are regressed on firm value. The results indicated that contemporaneous exchange rate changes have a negative significant influence on the value of nonfinancial companies listed at the Nairobi Securities Exchange. The results of the study were inconclusive on the effects of lagged changes in exchange rates on firm value. The findings of the study reveal that unexpected exchange rate changes have a significant negative influence on firm value.

Abstract 5532: Serum progranulin (GP88) level correlates with change in RECIST and survival in metastatic breast cancer

Abstract Monitoring of disease status in metastatic breast cancer (MBC) patients is a necessary step for optimal clinical management of patients during and post-therapy. While imaging technologies are the methods of choice in the standard of care (SOC), they are expensive, time-consuming, and have limited sensitivity. Measurements of circulating tumor markers CA15-3, CA125 and CEA have provided, albeit with limitation, minimally invasive methods for MBC disease management. An ideal approach would be to measure biomarkers involved in tumor biological processes, as they may provide better evaluation of the disease state and thus aid in real-time clinical management of MBC patients. The 88kDa glycoprotein Progranulin (GP88/PGRN) fit these criteria. GP88/PGRN is expressed in tumor tissue and not in normal mammary tissue counterpart and is secreted into the circulation of BC patients. Biological studies have established GP88/PGRN as a critical driver of BC cell proliferation, survival, invasiveness and drug resistance. Clinical studies have demonstrated that high tumor GP88/PGRN expression was prognostic for recurrence and that BC patients had a statistically elevated GP88/PGRN serum level compared to healthy individuals. In the present study, we examined whether GP88/PGRN serum levels were elevated in MBC patients and whether GP88 serum levels were correlated to patient survival and to a change in disease status as measured by RECIST 1.1. An IRB approved protocol at the University of Maryland Greenebaum Comprehensive Cancer Center consented and enrolled 101 stage 4 BC patients undergoing SOC therapy. Patient demographics, together with clinical and disease characteristics by RECIST were collected. Blood samples were collected from each patient at follow-up visits during and post-therapy and tested for GP88 using A&G's GP88 enzyme linked immunoassay. Statistical analyses established a GP88 cut-off value associated with overall survival as well as determined that GP88 level was associated with disease status measured by RECIST criteria. Kaplan-Meier functions established a correlation between GP88 serum level and overall survival in MBC patients that was independent from age, race, tumor characteristics, receptor status and metastatic burden (number and sites of metastasis). Additionally, we examined the data to investigate if change in GP88 serum levels correlated with a contemporaneous change (Progression vs Response) in RECIST/ Clinical findings. Statistical analysis determined that contemporaneous GP88 is significantly associated with disease progression (p=0.0101) and response (p=0.0194). We conclude that circulating levels of GP88/PGRN in MBC patients are correlated with overall survival and disease status and that monitoring circulating GP88/PGRN levels would provide additional information and valuable insight into real-time MBC disease status. Citation Format: Ginette Serrero, David Hicks, Douglas Hawkins, Binbin Yue, Paula Rosenblatt, Nancy Tait, Katherine Tkaczuk. Serum progranulin (GP88) level correlates with change in RECIST and survival in metastatic breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5532.

Global risk factors in the returns of listed private equity

PurposeThe purpose of this paper is, to study macroeconomic risk factors driving the expected stock returns of listed private equity (LPE). The authors use LPE indices divided into different styles and regions from January 2004 to December 2016 and a set of country stock indices to estimate the macroeconomic risk profiles and corresponding risk premiums. Using a seemingly unrelated regressions (SUR) model to estimate factor sensitivities, the authors document that LPE indices exhibit stock market βs that are greater than 1. A one-factor asset pricing model using world stock market returns as the only possible risk factor is rejected on the basis of generalized method of moments (GMM) orthogonality conditions. In contrast, using the change in a currency basket, the G-7 industrial production, the G-7 term spread, the G-7 inflation rate and a recently proposed indicator of economic policy uncertainty as additional risk factors, this multifactor model is able to price a cross-section of expected LPE returns. The risk-return profile of LPE differs from country equity indices. Consequently, LPE should be treated as a separate asset class.Design/methodology/approachFollowing Ferson and Harvey (1994), the authors use an unconditional asset pricing model to capture the structure of returns across LPE. The authors use 11 LPE indices divided into different styles and regions from January 2004 to December 2016, and a set of country stock indices as spanning assets to estimate the macroeconomic risk profiles and corresponding risk premiums.FindingsUsing a seemingly unrelated regressions (SUR) model to estimate factor sensitivities, the authors document that LPE indices exhibit stock market ßs that are greater than 1. The authors estimate a one-factor asset pricing model using world stock market returns as the only possible risk factor by GMM. This model is rejected on the basis of the GMM orthogonality conditions. By contrast, a multifactor model built on the change in a currency basket, the G-7 industrial production, the G-7 term spread, the G-7 inflation rate and a recently proposed indicator of global economic policy uncertainty as additional risk factors is able to price a cross-section of expected LPE returns.Research limitations/implicationsGiven data availability, the authors’ sample is strongly influenced by the financial crisis and its aftermath.Practical implicationsInformation about the risk profile of LPE is important for asset allocation decisions. In particular, it may help to optimally react to contemporaneous changes in economy-wide risk factors.Originality/valueTo the best of authors’ knowledge, this is the first LPE study which investigates whether a set of macroeconomic factors is actually priced and, therefore, associated with a non-zero risk premium in the cross-section of returns.

SHRIMP U–Pb ages of detrital zircons from the Early Cretaceous Nakdong Formation, South East Korea: Timing of initiation of the Gyeongsang Basin and its provenance

AbstractTo constrain the depositional age of the lowermost Nakdong Formation in the Early Cretaceous Gyeongsang Basin, SHRIMP U–Pb age determination was carried out on zircon separates. The U–Pb compositions of detrital zircons from the Nakdong Formation yield a wide range of ages from the Archean to the Cretaceous but show a marked contrast in age distribution according to the geographical locations within the basin. The provenance of the southern Nakdong Formation is dominantly the surrounding Yeongnam Massif, which is composed of Paleoproterozoic metamorphic rocks and Triassic to Jurassic plutonic rocks, whereas the central to northern Nakdong Formation records significant sediment derivation from the Okcheon Metamorphic Belt, which is distributed to the northwest, in addition to the contribution from the Yeongnam Massif. It is suggested that the maximum depositional age of the Nakdong Formation is ca 127 Ma, based on its youngest detrital zircon age population. The onset of its deposition at 127 Ma coincided with the tectonic inversion in East Asia from a compressional to an extensional geodynamic setting, probably due to the contemporaneous change in the drift direction of the Izanagi Plate and its subsequent oblique subduction.

Spatial variation in Late Ordovician glacioeustatic sea-level change

Mass extinction of Late Ordovician marine fauna closely coincided with southern hemisphere glaciation. The sequence stratigraphic architecture of shallow marine deposits informs estimates of glacioeustatic sea-level change at sites both proximal and distal to the reconstructed Ordovician ice sheet(s) and contemporaneous changes in ice volume. A recent correlation framework for the stratigraphic architectures of one near and one far field Late Ordovician margin concluded that the Late Ordovician glaciation encompassed multiple long-term cycles of ice volume growth and retreat with superimposed higher frequency cycles. Here we posit that—similar to Cenozoic glacial cycles—glacial isostatic adjustment can preclude synchronous and similar magnitude (or directional) changes in Late Ordovician sea level between ice proximal and ice distal locations and, hence, distort a globally correlative sequence stratigraphy. We explored whether long-duration (i.e., million year) Late Ordovician glacial cycles should produce a globally coherent, eustatic record of sea-level change between ice proximal and ice distal margins using a gravitationally self-consistent theory that accounts for the deformational, gravitational and rotational perturbations to sea level on a viscoelastic Earth model. We adopted a Late Ordovician paleogeography and a synthetic continental ice-sheet distribution and volume informed by the areal extent of glaciogenic deposits and geochemical records, respectively. We demonstrate that modeled million year Late Ordovician glacial cycles produce sea-level histories on near and far field margins that differ from eustasy, and from one another, due primarily to elastic flexure and associated gravitational effects. While predicted far-field sea-level histories faithfully preserve the temporal structure of modeled glacioeustasy, their amplitude may differ from eustasy by as much as 30–40%. The impact of glacial isostatic adjustment is largest at the margins of glaciated continents, and these effects can be of the same order of magnitude as the eustatic, and even induce a local sea-level rise during an episode of ice growth and eustatic sea-level fall, and vice versa. In this regard, stratal surfaces of maximum regression and flooding expressed at near-field margins need not reflect global (‘eustatic’) trends in ice sheet growth and decay, respectively, and thus may not provide chronostratigraphic horizons for correlation with far-field sequence stratigraphic architectures.

Impact of involvement of non-formal health providers on TB case notification among migrant slum-dwelling populations in Odisha, India.

BackgroundMigrant labourers living in the slums of urban and industrial patches across India make up a key sub-population so far controlling Tuberculosis (TB) in the country is concerned. This is because many TB patients from these communities- remain under reached by the Revised National Tuberculosis Control Programme (RNTCP) of India. This marginalized community usually seeks early-stage healthcare from “friendly neighbourhood” non-formal health providers (NFHPs). Because, RNTCP has limited capacity to involve the NFHPs, an implementation research project was conceived, whereby an external partner would engage with the NFHPs to enable them to identify early TB symptomatics from this key sub-population who would be then tested using Xpert MTB/RIF technology. Diagnosed TB cases among them would be referred promptly to RNTCP for treatment. This paper aimed to describe the project and its impact.MethodsAdopting a quasi-experimental before-after design, four RNTCP units from two major urban-industrial areas of Odisha were selected for intervention, which spanned five quarters and covered 151,400 people, of which 30% were slum-dwelling migrants. Two similar units comprised the control population. The hypothesis was, reaching the under reached in the intervention area through NFHPs would increase TB notification from these traditionally under-notifying units.RNTCP notification data during intervention was compared with pre-intervention era, adjusted for contemporaneous changes in control populationResultsThe project detected 488 Xpert+ TB cases, of whom 466 were administered RNTCP treatment. This translated into notification of additional 198 new bacteriologically positive cases to RNTCP, a 30% notification surge, after adjustment for 2% decline in control. This meant an average quarterly increase in notification of 41.20(20.08, 62.31; p<0.001) cases. The increase was immediate, evident from the rise in level in the time series analysis by 50.42(10.28, 90.55; p = 0.02) cases.ConclusionEngagement with NFHPs contributed to an increase in TB notification to RNTCP from key under reached, slum-dwelling migrant populations.

Medical marijuana laws and adolescent marijuana use in the United States: a systematic review and meta-analysis.

AimsTo conduct a systematic review and meta‐analysis of studies in order to estimate the effect of US medical marijuana laws (MMLs) on past‐month marijuana use prevalence among adolescents.MethodsA total of 2999 papers from 17 literature sources were screened systematically. Eleven studies, developed from four ongoing large national surveys, were meta‐analyzed. Estimates of MML effects on any past‐month marijuana use prevalence from included studies were obtained from comparisons of pre–post MML changes in MML states to changes in non‐MML states over comparable time‐periods. These estimates were standardized and entered into a meta‐analysis model with fixed‐effects for each study. Heterogeneity among the study estimates by national data survey was tested with an omnibus F‐test. Estimates of effects on additional marijuana outcomes, of MML provisions (e.g. dispensaries) and among demographic subgroups were abstracted and summarized. Key methodological and modeling characteristics were also described. Preferred Reporting Items for Systematic Reviews and Meta‐Analyses (PRISMA) guidelines were followed.ResultsNone of the 11 studies found significant estimates of pre–post MML changes compared with contemporaneous changes in non‐MML states for marijuana use prevalence among adolescents. The meta‐analysis yielded a non‐significant pooled estimate (standardized mean difference) of −0.003 (95% confidence interval = −0.012, +0.007). Four studies compared MML with non‐MML states on pre‐MML differences and all found higher rates of past‐month marijuana use in MML states pre‐MML passage. Additional tests of specific MML provisions, of MML effects on additional marijuana outcomes and among subgroups generally yielded non‐significant results, although limited heterogeneity may warrant further study.ConclusionsSynthesis of the current evidence does not support the hypothesis that US medical marijuana laws (MMLs) until 2014 have led to increases in adolescent marijuana use prevalence. Limited heterogeneity exists among estimates of effects of MMLs on other patterns of marijuana use, of effects within particular population subgroups and of effects of specific MML provisions.

Late Glacial Human Dispersals in Northern Europe and Disequilibrium Dynamics

There is mounting evidence for the non-analogue nature of Late Glacial (18,000–11,700 years BP) ecosystems. Several dispersal episodes of human forager groups moving into previously uninhabitable glacial or periglacial landscapes also occurred during this period. In palaearctic northern Europe, these dispersals are associated with a succession of archaeological technocomplexes that are traditionally thought to reflect changing adaptation strategies synchronised with contemporaneous environmental changes. Recent investigations into ecological disequilibrium dynamics suggest, however, that there may be a greater degree of mismatch between organisms and their environments, especially in arctic-type environments and during times of rapidly changing climate. We link these climatic changes to cultural changes via demographic inference. Based on recent dating evidence, environmental analyses and preliminary morphometric and technological analyses of lithic material, we infer that Late Glacial Palearctic foragers, similarly at disequilibrium and with very low population densities, were prone to regional extinction episodes. We focus in particular on ‘Hamburgian’ culture and its potentially failed dispersal into southern Scandinavia. In conclusion, we suggest avenues for further testing this hypothesis of regional extinction.

Public R&amp;D Support and Firms' Performance: A Panel Data Study

We analyse all the major sources of direct and indirect R&D subsidies in Norway in the period 2002-2013 and compare their effects on individual firms' performance. Firms that received support are matched with a control group of firms that did not receive support using a combination of stratification and propensity score matching. Changes in performance indicators before and after support in the treatment group are compared with contemporaneous changes in the control group. We find that the average effects of R&D support among those who obtained grants and/or subsidies are positive and significant in terms of performance indicators related to economic growth: value added, sales revenue and number of employees. The estimated effects are larger for start-up firms than incumbent firms when the effects are measured as relative effects (in percentage points), but smaller when these effects are translated into level effects. Finally, we do not find positive effects on return to total assets or productivity for firms who received support compared with the control group.

Public R&amp;D Support and Firmss Performance -- A Panel Data Study.

We analyse all the major sources of direct and indirect R&D subsidies in Norway in the period 2002- 2013 and compare their effects on individual firms’ performance. Firms that received support are matched with a control group of firms that did not receive support using a combination of stratification and propensity score matching. Changes in performance indicators before and after support in the treatment group are compared with contemporaneous changes in the control group. We find that the average effects of R&D support among those who obtained grants and/or subsidies are positive and significant in terms of performance indicators related to economic growth: value added, sales revenue and number of employees. The estimated effects are larger for start-up firms than incumbent firms when the effects are measured as relative effects (in percentage points), but smaller when these effects are translated into level effects. Finally, we do not find positive effects on return to total assets or productivity for firms who received support compared with the control group.

Taxation and Innovation in the 20th Century

This paper studies the effect of corporate and personal taxes on innovation in the United States over the twentieth century. We use three new datasets: a panel of the universe of inventors who patent since 1920; a dataset of the employment, location and patents of firms active in RD and a historical state-level corporate tax database since 1900, which we link to an existing database on state-level personal income taxes. Our analysis focuses on the impact of taxes on individual inventors and firms (the micro level) and on states over time (the macro level). We propose several identification strategies, all of which yield consistent results: i) OLS with fixed effects, including inventor and state-times-year fixed effects, which make use of differences between tax brackets within a state-year cell and which absorb heterogeneity and contemporaneous changes in economic conditions; ii) an instrumental variable approach, which predicts changes in an individual or firm's total tax rate with changes in the federal tax rate only; iii) event studies, synthetic cohort case studies, and a border county strategy, which exploits tax variation across neighboring counties in different states. We find that taxes matter for innovation: higher personal and corporate income taxes negatively affect the quantity and quality of inventive activity and shift its location at the macro and micro levels. At the macro level, cross-state spillovers or business-stealing from one state to another are important, but do not account for all of the effect. Agglomeration effects from local innovation clusters tend to weaken responsiveness to taxation. Corporate inventors respond more strongly to taxes than their non-corporate counterparts.