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Integration of research experiences into the undergraduate classroom can result in increased recruitment, retention, and motivation of science students. 'Big data' science initiatives, such as the Paleobiology Database (PBDB), can provide inexpensive and accessible research opportunities. This Element provides an introduction to what the PBDB is, how to use it, how it can be deployed in introductory and advanced courses, and examples of how it has been used in undergraduate research. The PBDB aims to provide information on all fossil organisms, across the tree of life, around the world, and through all of geologic time. The PBDB Resource Page contains a range of PBDB tutorials and activities for use in physical geology, historical geology, paleontology, sedimentology, and stratigraphy courses. As two-year colleges, universities, and distance-based learning initiatives seek research-based alternatives to traditional lab exercises, the PBDB can provide opportunities for hands-on science activities.
A once-dominant family of interpretations of the beginnings of Japanese and Russian development claimed that policies adopted by the two states were inadequate to modernize agrarian property relations, and so both states were required to mediate between premodern agriculture and “hot-house” modern industry. More recent accounts have insisted that despite the limited reforms to agrarian property relations, agriculture in both countries in fact dynamically participated in economic development. This paper contends that these revised accounts’ one-sided focus on market opportunities leaves unresolved key puzzles. Why did productivity growth jump higher after the Meiji reforms in Japan? Why did only some regions participate in agricultural development in Russia? To answer these questions, this paper argues it is necessary to return attention to the ways agrarian property relations did and did not change following reforms adopted by the two states in the 1860s and 1870s. The key theoretical upshot of this analysis is that the initiation of capitalist development required a political process in which institutions that had previously guaranteed non-market access of rural households to subsistence were dismantled in favor of the domination of market relations.
This paper identifies the individual components of social harm associated with a hypothetical racially targeted police encounter. Individuals who believe they are being targeted by police because they are members of a racial minority may suffer from fear of physical harm and humiliation by the encounter itself. However, the very fact that individuals will be racially targeted for a police encounter also causes harm to other members of the minority group even if they are not directly subject to an unwarranted encounter. In addition to fear and anxiety over the risk of such an encounter, they will often undertake costly avoidance behaviors to reduce their risk, or to mitigate the risk of any harm if such an encounter occurs. In addition, other members of society who value a nondiscriminatory policing policy might be willing to pay to reduce such unwarranted police encounters, and hence suffer a loss from this policing policy. In addition to discussing possible methodologies for estimating these cost components, this paper raises several issues that must be resolved – such as how to deal with the difference between perceived and actual racially targeted police encounters.
We have previously shown that the minor alleles of vascular endothelial growth factor A (VEGFA) single-nucleotide polymorphism rs833069 and superoxide dismutase 2 (SOD2) single-nucleotide polymorphism rs2758331 are both associated with improved transplant-free survival after surgery for CHD in infants, but the underlying mechanisms are unknown. We hypothesised that one or both of these minor alleles are associated with better systemic ventricular function, resulting in improved survival.
This study is a follow-up analysis of 422 non-syndromic CHD patients who underwent neonatal cardiac surgery with cardiopulmonary bypass. Echocardiographic reports were reviewed. Systemic ventricular function was subjectively categorised as normal, or as mildly, moderately, or severely depressed. The change in function was calculated as the change from the preoperative study to the last available study. Stepwise linear regression, adjusting for covariates, was performed for the outcome of change in ventricular function. Model comparison was performed using Akaike’s information criterion. Only variables that improved the model prediction of change in systemic ventricular function were retained in the final model.
Genetic and echocardiographic data were available for 335/422 subjects (79%). Of them, 33 (9.9%) developed worse systemic ventricular function during a mean follow-up period of 13.5 years. After covariate adjustment, the presence of the VEGFA minor allele was associated with preserved ventricular function (p=0.011).
These data support the hypothesis that the mechanism by which the VEGFA single-nucleotide polymorphism rs833069 minor allele improves survival may be the preservation of ventricular function. Further studies are needed to validate this genotype–phenotype association and to determine whether this mechanism is related to increased vascular endothelial growth factor production.
Taylor's law (TL) originated as an empirical pattern in ecology. In many sets of samples of population density, the variance of each sample was approximately proportional to a power of the mean of that sample. In a family of nonnegative random variables, TL asserts that the population variance is proportional to a power of the population mean. TL, sometimes called fluctuation scaling, holds widely in physics, ecology, finance, demography, epidemiology, and other sciences, and characterizes many classical probability distributions and stochastic processes such as branching processes and birth-and-death processes. We demonstrate analytically for the first time that a version of TL holds for a class of distributions with infinite mean. These distributions, a subset of stable laws, and the associated TL differ qualitatively from those of light-tailed distributions. Our results employ and contribute to the methodology of Albrecher and Teugels (2006) and Albrecher et al. (2010). This work opens a new domain of investigation for generalizations of TL.
In a family, parameterized by θ, of non-negative random variables with finite, positive second moment, Taylor's law (TL) asserts that the population variance is proportional to a power of the population mean as θ varies: σ2 (θ) = a[μ(θ)]b, a > 0. TL, sometimes called fluctuation scaling, holds widely in science, probability theory, and stochastic processes. Here we report diverse examples of TL with b = 2 (equivalent to a constant coefficient of variation) arising from a difference of random variables in normed vector spaces of dimension 1 and larger. In these examples, we compute a exactly using, in some cases, a simple, new technique. These examples may prove useful in future models that involve differences of random variables, including models of the spatial distribution and migration of human populations.
Placental vascular anastomoses in twins lead to a shared circulation and may subsequently enable the development of severe complications such as twin–twin transfusion syndrome (TTTS) and twin anemia–polycythemia sequence (TAPS). The presence of vascular anastomoses has frequently and systematically been studied in monochorionic (MC) placentas, but only rarely in dichorionic (DC) placentas. The aim of this study was to compare the prevalence of vascular anastomoses and evaluate the sharing discordance in MC and DC placentas. All consecutive placentas of MC and DC twins delivered at the Leiden University Medical Center (the Netherlands) and Medical University of Warsaw (Poland) from 2012 to 2015 were routinely injected with colored dye and included in the study. We excluded twin pregnancies treated with fetoscopic laser surgery. A total of 258 placentas were analyzed in this study, including 134 MC placentas and 124 DC placentas. Vascular anastomoses were present in 99% (133/134) of MC placentas and 0% of DC placentas (p < .01). Placental share discordance between MC twins was significantly larger compared to DC twins, 19.8 (interquartile range [IQR] 8.1–33.3) and 10.8 (IQR 6.2–19.0), respectively (p < .01). Vascular anastomoses associated complications occurred in 16% (22/134) MC twins. Our findings show that vascular anastomoses are almost ubiquitous in MC placentas, but non-existent in DC placentas. In addition, unequal placental sharing appears to be more common in MC than in DC placentas.
The Munro Review of Child Protection approached the problem of child
protection from an understanding based upon systems analysis. Risk
assessment in psychiatry has similarities to the assessment by social
workers of child protection issues. Psychiatry as a profession could learn
from the Review, and, in doing so, be supported in recovering and
communicating the requirements for good clinical practice.
This paper reports on a benefit-cost analysis of a targeted intervention program, the YouthBuild USA Offender Project (YBOP), aimed at low-income, criminal offenders who are 16–24 years old. Using data on 388 participants, we find: (1) evidence of reduced recidivism and improved educational outcomes that exceed our expectations based on similar cohorts and (2) evidence consistent with a positive benefit-cost ratio, indicating that every dollar spent on the YBOP is estimated to produce a return on investment between $7.20 and $21.60, with benefits to society ranging between $174,000 and $281,000 per participant at a cost to society between $13,000 and $24,000.
In radar receivers, the low noise amplifier (LNA) must provide very low noise figure and high gain to successfully receive very low signals reflected off of illuminated targets. Obtaining low noise figure and high gain, unfortunately, is a well-known trade-off that has been carefully negotiated by design engineers for years. This paper presents a fundamental solution method for the source reflection coefficient providing the maximum available gain under a given noise figure constraint, and also for the lowest possible noise figure under a gain constraint. The design approach is based solely on the small-signal S-parameters and noise parameters of the device; no additional measurements or information are required. This method is demonstrated through examples. The results are expected to find application in design of LNAs and in real-time reconfigurable amplifiers for microwave communication and radar receivers.
In the United States alone, ∼14,000 children are hospitalised annually with acute heart failure. The science and art of caring for these patients continues to evolve. The International Pediatric Heart Failure Summit of Johns Hopkins All Children’s Heart Institute was held on February 4 and 5, 2015. The 2015 International Pediatric Heart Failure Summit of Johns Hopkins All Children’s Heart Institute was funded through the Andrews/Daicoff Cardiovascular Program Endowment, a philanthropic collaboration between All Children’s Hospital and the Morsani College of Medicine at the University of South Florida (USF). Sponsored by All Children’s Hospital Andrews/Daicoff Cardiovascular Program, the International Pediatric Heart Failure Summit assembled leaders in clinical and scientific disciplines related to paediatric heart failure and created a multi-disciplinary “think-tank”. The purpose of this manuscript is to summarise the lessons from the 2015 International Pediatric Heart Failure Summit of Johns Hopkins All Children’s Heart Institute, to describe the “state of the art” of the treatment of paediatric cardiac failure, and to discuss future directions for research in the domain of paediatric cardiac failure.
Consumer protection and financial regulatory agencies such as the Federal Trade Commission (FTC), the Securities and Exchange Commission (SEC), and the Consumer Financial Protection Bureau (CFPB) regulate various types of consumer, investor and financial frauds. Whether required or not, rulemaking proceedings oftentimes include some form of benefit-cost analysis. Thus, the benefits of proposed regulations – whether fully quantified or not – are an increasingly important component of rulemaking decisions. Anecdotal evidence suggests that the impact on victims in some cases includes significant time and financial hardships and even pain, suffering, and reduced quality of life. Further, the existence of these offenses causes nonvictims to take costly precautionary behavior and might even inhibit legitimate business activities. Yet, little is known about the true costs of consumer and financial crimes other than the out-of-pocket monetary losses incurred by victims. To the extent society wishes to optimally deter such crimes, without better data on nonmonetary costs, any benefit-cost analyses of criminal justice or prevention programs designed to reduce these crimes will inevitably underestimate program benefits. This paper provides an initial framework and empirical estimates of the willingness to pay (WTP) to reduce four types of white-collar and corporate offenses – consumer fraud, financial fraud, corporate crime, and corporate financial crime. Utilizing a contingent valuation survey approach that has been used to estimate the cost of street crimes, the average WTP for a 10% reduction in each of these four offenses is estimated to range between $35 and $85 per household. In the case of consumer fraud and financial fraud, where estimates of prevalence are available, this translates into a WTP of $1200 per consumer fraud and $12,000 for financial fraud. In contrast, the out-of-pocket costs to victims of consumer fraud have been estimated to average about $100, and about $200 to $250 for various types of financial frauds. These figures also compare favorably to the WTP for a reduced household burglary of $19,000.
This study assessed the dimensionality of the Systemizing Quotient-Revised (SQ-R), a measure of how strong a person's interest is in systems, using two statistical approaches: Rasch modeling and Confirmatory Factor Analysis (CFA). Participants included N = 675 with an autism spectrum condition (ASC), N = 1369 family members of people with ASC, and N = 2014 typical controls. Data were applied to the Rasch model (Rating Scale) using WINSTEPS. The data fit the Rasch model quite well lending support to the idea that systemizing could be seen as unidimensional. Reliability estimates were .99 for items and .92 for persons. A CFA parceling approach confirmed that a unidimensional model fit the data. There was, however, differential functioning by sex in some of these items. An abbreviated 44-item version of the scale, consisting of items without differential item functioning by sex was developed. This shorter scale also was tested from a Rasch perspective and confirmed through CFA. All measures showed differences on total scale scores between those participants with and without ASC (d = 0.71, p < .005), and between sexes (d = 0.53, p < .005). We conclude that the SQ-R is an appropriate measure of systemizing which can be measured along a single dimension.