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Asymmetric distribution of information, while omnipresent in real markets, is rarely considered in experimental financial markets. We present results from experiments where subjects endogenously choose between five information levels (four of them costly). We find that (i) uninformed traders earn the highest net returns, while average informed traders always perform worst even when information costs are not considered; (ii) over time traders learn to pick the most advantageous information levels (full information or no information); and (iii) market efficiency decreases with higher information costs. These results are mostly in line with the theoretical predictions of Grossman and Stiglitz (Am. Econ. Rev. 70:393-408, 1980) and provide additional insights that studies with only two information levels cannot deliver.
There is a heated debate on whether markets erode social responsibility and moral behavior. However, it is a challenging task to identify and measure moral behavior in markets. Based on a theoretical model, we examine in an experiment the relation between trading volume, prices and moral behavior by setting up markets that either impose a negative externality on third parties or not. We find that moral behavior reveals itself in lower trading volume in markets with a negative externality, while prices mostly depend on the market structure. We further investigate individual characteristics that explain trading behavior in markets with negative externalities.
In this methodological study we analyze price adjustment processes in multi-period laboratory asset markets with five distinct fundamental value (FV) regimes in a unified framework. Minimizing the effect of between-treatment variations we run markets with deterministically decreasing, constant, randomly fluctuating and—as main innovation—markets with deterministically increasing FVs. We find (i) efficient pricing in markets with constant FVs, (ii) overvaluation in markets with decreasing FVs, and (iii) undervaluation in markets with increasing FVs. (iv) Markets with randomly fluctuating fundamentals show overvaluation when FVs predominantly decline and undervaluation when FVs are mostly upward-sloping. Finally, we document that (v) bid-ask spreads and volatility of price changes are positively correlated with mispricing across regimes. The main contribution of the paper is to provide clean comparisons between distinct FV regimes, in particular between markets with increasing FVs and other regimes.
We review bubble measures which are commonly used in the experimental asset market literature. It seems sensible to require that measures of mispricing should (i) relate the fundamental value and price, (ii) be monotone in the difference between fundamental value and price, and (iii) be independent of the total number of periods and the absolute level of fundamental value. We show that none of the measures currently used fulfills all these criteria. To facilitate comparability across different experimental settings with different parameterizations we propose two alternative measures which fulfill all evaluation criteria. The measure for mispricing, RAD (relative absolute deviation), is calculated by averaging absolute differences between the (volume-weighted) mean price and the fundamental value across all periods and normalizing it with the absolute value of the average FV of the market. The measure for overvaluation, RD (relative deviation), is calculated analogously, but uses raw difference between (volume-weighted) mean prices and fundamental values. Hence, it provides information on whether the mispricing stems from over- or undervaluation of the asset.
In 1988 Smith, Suchanek, and Williams (henceforth SSW) introduced a very influential model to test the efficiency of experimental asset markets. They and many subsequent studies observe that bubbles are robust to many treatment changes. Instead, bubbles are avoided only when subjects are experienced in the same setting, when the dividend-process is experienced by subjects beforehand, or when the fundamental value-process (FV) is presented in a well understandable context to reduce subjects’ confusion. We extend this line of research and show that even marginal changes in the experimental instructions/procedure can eliminate bubbles in the SSW-model. In particular, we show that mispricing is significantly reduced and overvaluation is eliminated completely (i) when the fundamental value process is displayed in a graph instead of a table or (ii) when subjects are asked about the current fundamental value at the beginning of each period. From a questionnaire conducted at the end of the experiment we infer that these treatment changes help to improve subjects’ understanding of the FV-process. We conclude that all bubble reducing factors have one common feature: they allow subjects to understand the non-intuitive declining FV-process of the SSW-model better and thus reduce subjects’ confusion about the FV-process.
We run laboratory experiments to analyze the impact of prior investment experience on price efficiency in asset markets. Before subjects enter the asset market they gain either no, positive, or negative investment experience in an investment game. To get a comprehensive picture about the role of experience we implement two asset market designs. One is prone to inefficient pricing, exhibiting bubble and crash patterns, while the other exhibits efficient pricing. We find that (i) both, positive and negative, experience gained in the investment game lead to efficient pricing in both market settings. Further, we show that (ii) the experience effect dominates potential effects triggered by positive and negative sentiment generated by the investment game. We conjecture that experiencing changing price paths in the investment game can create a higher sensibility on changing fundamentals (through higher salience) among subjects in the subsequently run asset market.
Blood-based biomarkers offer a more feasible alternative to Alzheimer’s disease (AD) detection, management, and study of disease mechanisms than current in vivo measures. Given their novelty, these plasma biomarkers must be assessed against postmortem neuropathological outcomes for validation. Research has shown utility in plasma markers of the proposed AT(N) framework, however recent studies have stressed the importance of expanding this framework to include other pathways. There is promising data supporting the usefulness of plasma glial fibrillary acidic protein (GFAP) in AD, but GFAP-to-autopsy studies are limited. Here, we tested the association between plasma GFAP and AD-related neuropathological outcomes in participants from the Boston University (BU) Alzheimer’s Disease Research Center (ADRC).
Participants and Methods:
This sample included 45 participants from the BU ADRC who had a plasma sample within 5 years of death and donated their brain for neuropathological examination. Most recent plasma samples were analyzed using the Simoa platform. Neuropathological examinations followed the National Alzheimer’s Coordinating Center procedures and diagnostic criteria. The NIA-Reagan Institute criteria were used for the neuropathological diagnosis of AD. Measures of GFAP were log-transformed. Binary logistic regression analyses tested the association between GFAP and autopsy-confirmed AD status, as well as with semi-quantitative ratings of regional atrophy (none/mild versus moderate/severe) using binary logistic regression. Ordinal logistic regression analyses tested the association between plasma GFAP and Braak stage and CERAD neuritic plaque score. Area under the curve (AUC) statistics from receiver operating characteristics (ROC) using predicted probabilities from binary logistic regression examined the ability of plasma GFAP to discriminate autopsy-confirmed AD status. All analyses controlled for sex, age at death, years between last blood draw and death, and APOE e4 status.
Results:
Of the 45 brain donors, 29 (64.4%) had autopsy-confirmed AD. The mean (SD) age of the sample at the time of blood draw was 80.76 (8.58) and there were 2.80 (1.16) years between the last blood draw and death. The sample included 20 (44.4%) females, 41 (91.1%) were White, and 20 (44.4%) were APOE e4 carriers. Higher GFAP concentrations were associated with increased odds for having autopsy-confirmed AD (OR=14.12, 95% CI [2.00, 99.88], p=0.008). ROC analysis showed plasma GFAP accurately discriminated those with and without autopsy-confirmed AD on its own (AUC=0.75) and strengthened as the above covariates were added to the model (AUC=0.81). Increases in GFAP levels corresponded to increases in Braak stage (OR=2.39, 95% CI [0.71-4.07], p=0.005), but not CERAD ratings (OR=1.24, 95% CI [0.004, 2.49], p=0.051). Higher GFAP levels were associated with greater temporal lobe atrophy (OR=10.27, 95% CI [1.53,69.15], p=0.017), but this was not observed with any other regions.
Conclusions:
The current results show that antemortem plasma GFAP is associated with non-specific AD neuropathological changes at autopsy. Plasma GFAP could be a useful and practical biomarker for assisting in the detection of AD-related changes, as well as for study of disease mechanisms.
Chronic traumatic encephalopathy (CTE) is a neurodegenerative disease that can only be diagnosed at post-mortem. Revised criteria for the clinical syndrome of CTE, known as traumatic encephalopathy syndrome (TES), include impairments in episodic memory and/or executive function as core clinical features. These criteria were informed by retrospective interviews with next-of-kin and the presence and rates of objective impairments in memory and executive functions in CTE are unknown. Here, we characterized antemortem neuropsychological test performance in episodic memory and executive functions among deceased contact sport athletes neuropathologically diagnosed with CTE.
Participants and Methods:
The sample included 80 deceased male contact sport athletes from the UNITE brain bank who had autopsy-confirmed CTE (and no other neurodegenerative diseases). Published criteria were used for the autopsy diagnosis of CTE. Neuropsychological test reports (raw scores) were acquired through medical record requests. Raw scores were converted to z-scores using the same age, sex, and education-adjusted normative data. Tests of memory included long delay trials from the Rey Complex Figure, CVLT-II, HVLT-R, RBANS, and BVMT-R. Tests of executive functions included Trail Making Test-B (TMT-B), Controlled Oral Word Association Test, WAIS-III Picture Arrangement, and various WAIS-IV subtests. Not all brain donors had the same tests, and the sample sizes vary across tests, with 33 donors having tests from both domains. Twenty-eight had 1 test in memory and 3 had 2+. Eight had 1 test of executive function and 46 had 2+. A z-score of 1.5 standard deviations below the normative mean was impaired. Interpretation of test performance followed the American Academy of Clinical Neuropsychology guidelines (Guilmette et al., 2020). Bivariate correlations assessed cumulative p-tau burden (summary semiquantitative ratings of p-tau severity across 11 brain regions) and TMT-B (n=34) and CVLT-II (n=14), the most common tests available.
Results:
Of the 80 (mean age= 59.9, SD=18.0 years; 13, 16.3% were Black), 72 played football, 4 played ice hockey, and 4 played other contact sports. Most played at the professional level (57, 71.3%). Mean time between neuropsychological testing and death was 3.9 (SD= 4.5) years. The most common reason for testing was dementia-related (43, 53.8%). Mean z-scores fell in the average psychometric range(mean z= -0.52, SD=1.5, range= -6.0 to 3.0) for executive function and the low average range for memory (mean z= -1.3, SD=1.1, range= -4.0 to 2.0). Eleven (20.4%) had impairment on 1 test and 3 (5.6%) on 2+ tests of executive functions. The most common impairment was on TMT-B (mean z= -1.77, 13 [38.2%] impaired). For memory, 13 (41.9%) had impairment on 1 test. Of the 14 who had CVLT-II, 7 were impaired (mean z= -1.33). Greater p-tau burden was associated with worse performance on CVLT-II (r= -.653, p= .02), but not TMT-B (r= .187, p>.05).
Conclusions:
This study provides the first evidence for objectively-measured impairments in executive functions and memory in a sample with known, autopsy-confirmed CTE. Furthermore, p-tau burden corresponded to worse memory test performance. Examination of neuropsychological tests from medical records has limitations but can overcome shortcomings of retrospective informant reports to provide insight into the cognitive profiles associated with CTE.
While the quasilinear isothermal Euler equations are an excellent model for gas pipeline flow, the operation of the pipeline flow with high pressure and small Mach numbers allows us to obtain approximate solutions by a simpler semilinear model. We provide a derivation of the semilinear model that shows that the semilinear model is valid for sufficiently low Mach numbers and sufficiently high pressures. We prove an existence result for continuous solutions of the semilinear model that takes into account lower and upper bounds for the pressure and an upper bound for the magnitude of the Mach number of the gas flow. These state constraints are important both in the operation of gas pipelines and to guarantee that the solution remains in the set where the model is physically valid. We show the constrained exact boundary controllability of the system with the same pressure and Mach number constraints.
Despite the ongoing success of populist parties in many parts of the world, we lack comprehensive information about parties’ level of populism over time. A recent contribution to Political Analysis by Di Cocco and Monechi (DCM) suggests that this research gap can be closed by predicting parties’ populism scores from their election manifestos using supervised machine learning. In this paper, we provide a detailed discussion of the suggested approach. Building on recent debates about the validation of machine-learning models, we argue that the validity checks provided in DCM’s paper are insufficient. We conduct a series of additional validity checks and empirically demonstrate that the approach is not suitable for deriving populism scores from texts. We conclude that measuring populism over time and between countries remains an immense challenge for empirical research. More generally, our paper illustrates the importance of more comprehensive validations of supervised machine-learning models.
Nosocomial transmission of influenza is a major concern for infection control. We aimed to dissect transmission dynamics of influenza, including asymptomatic transmission events, in acute care.
Design:
Prospective surveillance study during 2 influenza seasons.
Setting:
Tertiary-care hospital.
Participants:
Volunteer sample of inpatients on medical wards and healthcare workers (HCWs).
Methods:
Participants provided daily illness diaries and nasal swabs for influenza A and B detection and whole-genome sequencing for phylogenetic analyses. Contacts between study participants were tracked. Secondary influenza attack rates were calculated based on spatial and temporal proximity and phylogenetic evidence for transmission.
Results:
In total, 152 HCWs and 542 inpatients were included; 16 HCWs (10.5%) and 19 inpatients (3.5%) tested positive for influenza on 109 study days. Study participants had symptoms of disease on most of the days they tested positive for influenza (83.1% and 91.9% for HCWs and inpatients, respectively). Also, 11(15.5%) of 71 influenza-positive swabs among HCWs and 3 (7.9%) of 38 influenza-positive swabs among inpatients were collected on days without symptoms; 2 (12.5%) of 16 HCWs and 2 (10.5%) of 19 inpatients remained fully asymptomatic. The secondary attack rate was low: we recorded 1 transmission event over 159 contact days (0.6%) that originated from a symptomatic case. No transmission event occurred in 61 monitored days of contacts with asymptomatic influenza-positive individuals.
Conclusions:
Influenza in acute care is common, and individuals regularly shed influenza virus without harboring symptoms. Nevertheless, both symptomatic and asymptomatic transmission events proved rare. We suggest that healthcare-associated influenza prevention strategies that are based on preseason vaccination and barrier precautions for symptomatic individuals seem to be effective.
In this chapter the major conservation issues bears face is reviewed and management actions that can address these conservation issues are highlighted. The future of bears across the world is bright for some species but dark for others. In some areas such as North America and in parts of Europe and Asia, bear populations have increased and stabilized because of increased management effort and increasing support for bears and their needs by the humans who share habitat with them. However, for most bear species, the future is uncertain. Andean bears continue to be threatened by habitat loss and human encroachment. In much of Asia outside Japan, Asiatic black bear, sloth bear, and sun bear populations are increasingly threatened by unmanaged excessive mortality combined with habitat loss to timber harvest, plantation agriculture, and human encroachment. The long-term future for polar bears is threatened by the unmanageable threat of climate change. Giant pandas are fragmented into small populations despite intense conservation efforts. Improving public and political support for bears is the most important need if we are to realize successful bear conservation and management.
To assess influenza symptoms, adherence to mask use recommendations, absenteesm and presenteeism in acute care healthcare workers (HCWs) during influenza epidemics.
Methods:
The TransFLUas influenza transmission study in acute healthcare prospectively followed HCWs prospectively over 2 consecutive influenza seasons. Symptom diaries asking for respiratory symptoms and adherence with mask use recommendations were recorded on a daily basis, and study participants provided midturbinate nasal swabs for influenza testing.
Results:
In total, 152 HCWs (65.8% nurses and 13.2% physicians) were included: 89.1% of study participants reported at least 1 influenza symptom during their study season and 77.8% suffered from respiratory symptoms. Also, 28.3% of HCW missed at least 1 working day during the study period: 82.6% of these days were missed because of symptoms of influenza illness. Of all participating HCWs, 67.9% worked with symptoms of influenza infection on 8.8% of study days. On 0.3% of study days, symptomatic HCWs were shedding influenza virus while at work. Among HCWs with respiratory symptoms, 74.1% adhered to the policy to wear a mask at work on 59.1% of days with respiratory symptoms.
Conclusions:
Respiratory disease is frequent among HCWs and imposes a significant economic burden on hospitals due to the number of working days lost. Presenteesm with respiratory illness, including influenza, is also frequent and poses a risk for patients and staff.
Public support is usually a precondition for the adoption and successful implementation of costly policies. We argue that such support is easier to achieve with policy-packages that incorporate primary and ancillary measures. We specifically distinguish command-and-control and market-based measures as primary measures and argue that the former will usually garner more public support than the latter given the low-visibility tendency of costs associated with command-and-control measures. Nevertheless, if included in a policy-package, ancillary measures are likely to increase public support by reducing negative effects of primary measures. Based on a choice experiment with a representative sample of 2,034 Swiss citizens, we assessed these arguments with respect to political efforts to reduce vehicle emissions. The empirical analysis supported the argument that policy-packaging affects public support positively, particularly generating more support when ancillary measures are added. Lastly, we ultimately observe that command-and-control measures obtain more public support than market-based instruments.
The objective of this study was to evaluate growth and seed production of giant foxtail under different N sources (NO3 and NH4) and N fertilizer application rates. Nitrate and NH4 fertilizers plus nitrification inhibitor were applied at 56, 112, and 225 kg N ha−1 under field conditions, and in the greenhouse four N rates (1, 5, 10, and 25 mM N) were applied in three NO3: NH4 ratios (100 : 0, 50 : 50, 0 : 100). Growth of giant foxtail was affected by N rates under both greenhouse and field conditions. In 1993, abundant rainfall in May and June allowed a rapid and earlier uptake of N by giant foxtail, resulting in larger plants with greater N accumulation and higher numbers of heads and seeds than in 1994. Total dry weight increased with increasing N rates; however, seed production reached a maximum at approximately 150 kg N ha−1. Nitrogen translocation efficiency decreased with increasing N rates. Giant foxtail did not show any preference to N form; however, seed production was reduced when the high N rate was applied as NH4 compared to NO3. These results suggest that NH4 fertilizer applications with a long-term nitrification inhibitor could reduce the seed production of giant foxtail and its contribution to the soil seedbank for subsequent growing seasons.
The NASA/DLR Stratospheric Observatory for Infrared Astronomy (SOFIA), a 2.5-meter infrared telescope on board a Boeing 747-SP, will conduct 0.3 - 1,600 μm photometric, spectroscopic, and imaging observations from altitudes as high as 45,000 ft., where the average atmospheric transmission is greater than 80 percent. SOFIA's first light cameras and spectrometers, as well as future generations of instruments, will make important contributions to the characterization of the physical properties of exoplanets. Our analysis shows that optical and near-infrared photometric and spectrophotometric follow-up observations during planetary transits and eclipses will be feasible with SOFIA's instrumentation, in particular the HIPO-FLITECAM optical/NIR instruments. The airborne-based platform has unique advantages in comparison to ground- and space-based observatories in this field of research which we will outline here. Furthermore we will present two exemplary science cases, that will be conducted in SOFIA's cycle 1.
Contemporary social theory considers the growth of risk to be a distinguishing feature of modernity (e.g. Beck 1992; Giddens 1991; Luhmann 1993). The broad agreement among social scientists ceases where they explain the emergence and diffusion of risk as a comprehensive management tool. We can roughly distinguish between an explanatory strategy that conceptualises risk as a substantive event, and one that understands risk as an organising concept.
Becks' Risk Society (1992) is the primary example of a substantive notion of risk. In his theory, Beck identified two, tightly interrelated triggers for the increasing concern with risk. When risks capture the unintended, often disastrous consequences of modern, industrial production and technology, these (technological) failures attract attention where social institutions fail to cope with the effects of technological progress (Beck 1992). Hence, risk signals a rising societal vulnerability and a growing friction between technology, risk management and societal institutions. Thus, ‘risk’ indicates a loss of technological and societal control.
Contrary to this view, authors like Ericson et al. (2000), Luhmann (1993 and 1998) or Power (2004) suggest that risk is a concept for managing future developments. It is not institutional vulnerability that risk flags, but rather the expanding control it provides. And there is an in-built growth mechanism. To escape the inevitable contingencies of the future, these authors suggest, it should not be opted for certainty and security, but ‘the solution … is based on the acceptance and elaboration of the problem, on the multiplication and specification of the risks’ (Luhmann 1993: 76).
The freedom of movement of persons is one of the core tenets of the European Union. Immigration however is often seen as a cause for concern amongst native workers, as rising labour supply may threaten jobs and create downward pressure on wages. National politicians are increasingly under pressure to guard against it — in times of recession particularly. Despite this, there is evidence that highly-skilled migrant labour has the potential to raise competitiveness significantly and in theory this may feed into productivity. In this paper, we explore first the composition of inward migration to the EU and within the EU, concentrating specifically on the role of the highly-skilled and the extent to which migrants are overqualified within their jobs. We then analyse whether migrant workers affect productivity at the sectoral level. We find under-utilisation of skilled foreign labour and there is little evidence in general to suggest that migrants have raised productivity which may in part be attributable to over-qualification. However, we find robust evidence that migrants — particularly highly-skilled migrants — play a positive role in productivity developments in industries which are classified as ‘skill intensive’.