Bargaining over beauty: The economics of contracts in Renaissance art markets

This paper argues that concerns over opportunism affected the content and structure of Renaissance art contracts. Building on insights from the economic analysis of contracts, we first show that opportunism threatened the relationship between buyer—the patron—and seller—the painter—in Renaissance Italy. We then test the effect of opportunism on the contracting process for paintings against a novel data set on the content and structure of ninety documents corresponding to as many commissions. Our results provide evidence that concerns over opportunism had a systematic effect on the trading parties’ choice of how much and what to include in the contract governing their ex-change.

The Kaiser-Rocket effect: three decades and counting

The peculiar motion of the observer, if not accurately accounted for, is bound to induce a well-defined clustering signal in the distribution of galaxies. This signal is related to the Kaiser rocket effect. Here we examine the amplitude and form of this effect, both analytically and numerically, and discuss possible implications for the analysis and interpretation of forthcoming cosmological surveys. For an idealistic cosmic variance dominated full-sky survey with a Gaussian selection function peaked at z ∼ 1.5 it is a > 5σ effect and it can in principle bias very significantly the inference of cosmological parameters, especially for primordial non-Gaussianity. For forthcoming surveys, with realistic masks and selection functions, the Kaiser rocket is not a significant concern for cosmological parameter inference except perhaps for primordial non-Gaussianity studies. However, it is a systematic effect, whose origin, nature and imprint on galaxy maps are well known and thus should be subtracted or mitigated. We present several approaches to do so.

Effect of exposure to antibiotics on the gut microbiome and biochemical indexes of pregnant women

IntroductionExposure to antibiotics (ABX) during pregnancy can have a systematic effect on both fetal and maternal health. Although previous biomonitoring studies have indicated the effects on children of extensive exposure to ABX, studies on pregnant women remain scarce. To explore the effect on pregnant women of environmental exposure to ABX through accidental ingestion and identify potential health risks, the present study investigated 122 pregnant women in East China between 2019 and 2020.Research design and methodsThe presence of six categories of ABX (quinolones, sulfonamides, lincosamides, tetracyclines, amide alcohol ABX, and β-lactams) in plasma samples taken from the pregnant women was investigated using an ABX kit and a time-resolved fluorescence immunoassay.ResultsAll six ABX were detected in the plasma, with a detection rate of 17.2%. It was discovered that the composition of intestinal flora in pregnant women exposed to ABX was different from that of pregnant women who had not been exposed to ABX. The intestinal flora of pregnant women exposed to ABX also changed at both the phylum and genus levels, and several genera almost disappeared. Furthermore, the metabolic levels of glucose and insulin and the alpha diversity of pregnant women exposed to ABX were higher than those of pregnant women not exposed to ABX.ConclusionPregnant women are potentially at higher risk of adverse microbial effects. Glucose metabolism and insulin levels were generally higher in pregnant women exposed to ABX than in unexposed women. Also, the composition and color of the gut microbiome changed.

Leaf Surface Reflectance Does Not Affect Biophysical Traits Modelling from VIS-NIR Spectra in Plants with Sparsely Distributed Trichomes

In this study, we examine leaf reflectance as the main optical property used in remote sensing of vegetation. The total leaf reflectance consists of two main components: a diffuse component, originating from the leaf interior, and a component reflected directly from the leaf surface. The latter contains specular (mirror-like) reflectance (SR) and surface particle scattering, driven by the surface roughness. Our study aimed to (1) reveal the effects of key leaf structural traits on SR in 400–2500 nm, and (2) compare the performance of PLSR models of leaf biophysical properties based on the total reflectance and SR removal reflectance. Four Arabidopsis thaliana structural surface mutants and six Hieracium species differing in trichome properties were studied. PCA did not reveal any systematic effect of trichome density, length, and morphology on SR. Therefore, the results do not support the hypothesis that leaves with denser and longer trichomes have lower SR and higher total reflectance than the smooth leaves. SR removal did not remarkably improve PLSR models of biophysical traits (up to 2% of RMSE). Thus, in herbaceous dorsiventral leaves with relatively sparse trichomes of various morphology and without apparent waxy surface, we cannot confirm that SR removal significantly improves biophysical trait prediction.

A new framework for understanding systematic errors in cluster lens modelling. II. Constraint selection

Cluster lens models are affected by a variety of choices in the lens modelling process. We have begun a program to develop a systematics error budget for cluster lens modelling. Here we examine the selection of image constraints as a potential systematic effect. For constraining the mass model, we find that it is more important to have images be spatially distributed around the cluster than to have them distributed in redshift. We also find that some image sets appear to be more important than others in terms of how well they constrain the models; the ‘important’ image sets typically include an image that lies close to a lensing critical curve as well as an image that is relatively isolated from other images (providing constraints in a region that would otherwise lack lensing information). These conclusions can help guide observing programs that seek follow-up data for candidate lensed images.

Reference Measurement of Roundwood by Fringe Projection

The metrological verification of log scanners requires logs with accurately known dimensions as test objects. The measurement of the lengths and diameters must be traceable back to the SI (International System of Units) unit of length. The results have to be reported with the corresponding measurement uncertainties. The uncertainties are required to be 5 to 10 times lower than the corresponding maximum permissible errors allowed for the log scanner under test. This article presents a procedure for the reference measurement of logs using an off-the-shelf fringe projection system along with uncertainty budgets for the measured dimensions. The length and diameters are determined from the highly resolved mesh obtained by fringe projection using techniques from computational geometry and coordinate metrology. Corrections are applied to the length and diameter values to remove the systematic effect caused by scattering of projected light below the partially transparent log surface. The influence of the fringe projection system on the measured dimensions is determined by measurements of calibrated artifacts, which also provide the traceability back to the SI unit of length. The measurement is illustrated by the example of a log with a length of 2 m and a diameter of 280 mm. The corresponding uncertainty budgets, confirmed by repeat measurements, result in expanded uncertainties (confidence interval 95%) of 6 mm and 0.13 mm for length and diameter, respectively. These low values qualify the fringe projection measurement along with accompanying evaluation procedure to provide logs as reference objects for the verification of log scanners.

The Bouba-Kiki effect reflects generic shape-sound associations

Humans robustly associate spiky shapes to words like “Kiki” and round shapes to words like “Bouba”. A popular explanation is that the mouth forms an angular shape while saying “Kiki” and a rounded shape while saying “Bouba”, leading to this association. Alternatively, there could be generic associations between the shapes of objects and the sounds they produce. These possibilities can be distinguished using unpronounceable sounds: the mouth-shape hypothesis predicts no effect, whereas the generic shape hypothesis predicts a systematic effect. Here, we show that the Bouba-Kiki effect is present for a variety of unpronounceable sounds ranging from reversed versions of Bouba-like and Kiki-like words and natural real object sounds to even pure tones. The effect was strongly correlated with the mean frequency of a sound independent of its pronounceability. Thus, the Bouba-Kiki effect reflects generic associations between sounds and object shape rather than mouth shape.

Are flexible school start times associated with higher academic grades? A 4-year longitudinal study.

The mismatch between teenagers' late sleep phase and early school start time results in acute and chronic sleep reductions. This is not only harmful for students' learning in the short-term but may impact on students' career prospects and widen social inequalities. Delaying school start times has been shown to improve sleep but whether this translates to better achievement is unresolved. The current evidence is limited due to a plethora of outcome measures and the many factors influencing sleep and grade/score trajectories. Here, we studied whether 0.5-1.5 years of exposure to a flexible school start system, with the daily choice of an 8AM or 8:50AM-start (intervention), allowed secondary school students (n=63-157, 14-19 years) to improve their quarterly school grades in a 4-year longitudinal pre-post design. We investigated whether sleep, changes in sleep or frequency of later starts predicted grade improvements in the flexible system. Our mixed model regressions with 5,111-16,724 official grades as outcomes did not indicate meaningful grade improvements in the flexible system per se or with previously observed sleep variables (nor their changes) - the covariates academic quarter, discipline and grade level had a greater, more systematic effect in our sample. Importantly, this finding does not preclude improvements in learning and cognition in our sample. However, at the 'dose' received here, intermittent sleep benefits did not obviously translate into detectable grade changes, which is in line with several other studies and highlights that grades are suboptimal to evaluate timetabling interventions despite their importance for future success.

Can Contingency Fee Reforms Improve Maternal & Infant Health? Evidence from Nevada

Contingency fee laws are intended to reduce the amount of defensive medicine practiced by physicians, but their impact on such behavior is theoretically ambiguous. While nearly half of all states have adopted some type of contingency fee laws, very little empirical evidence exists with respect to related impacts, and no rigorous studies examine their potential impacts on health. We examine the impact of a particular contingency fee reform that occurred in Nevada in 2004 using synthetic control methods. Consistent with our expectations, we find a systematic increase in the C-section rate of less-educated mothers in Nevada after implementation of the reform. However, we find no systematic effect on infant mortality, suggesting that contingency reforms contribute to an increase in defensive medicine without a corresponding improvement in health.

Uncertainty, Spillovers, and Forecasts of the Realized Variance of Gold Returns

Using data for the group of G7 countries and China for the sample period 1996Q1 to 2020Q4, we study the role of uncertainty and spillovers for the out-of-sample forecasting of the realized variance of gold returns and its upside (good) and downside (bad) counterparts. We go beyond earlier research in that we do not focus exclusively on U.S.-based measures of uncertainty, and in that we account for international spillovers of uncertainty. Our results, based on the Lasso estimator, show that, across the various model configurations that we study, uncertainty has a more systematic effect on out-of-sample forecast accuracy than spillovers. Our results have important implications for investors in terms of, for example, pricing of related derivative securities and the development of portfolio-allocation strategies.