Systematic Quantitative Evidence Research Articles

Is the volatility of yields for major crops grown in Germany related to spatial diversification at county level?

Abstract Recent evidence suggests a stabilizing effect of crop diversity on agricultural production. However, different methods are used for assessing these effects and there is little systematic quantitative evidence on diversification benefits. The aim of this study was to assess the relationship between volatility of combined crop yields (denoted as standard deviation) and diversity (denoted as Shannon’s Evenness Index SEI) for standardized yield data of major crop species grown in Germany between 1977 and 2018 (winter wheat, winter barley, silage maize and winter rapeseed) at the county level. Portfolio theory was used to estimate the optimal crop area share for minimizing yield volatility. On average, results indicated a weak negative relationship between volatility and the SEI during the past decades for the case of Germany. Optimizing crop area shares for minimizing volatility reduced yield variance on average by 24 % but was associated with a decrease in SEI for most counties. This was related to the finding that the stability of individual species, i.e., barley and wheat, was more effective in reducing the volatility of combined yields than the asynchronous variation in annual yields among crops. Future studies might include an increased number of crop species and consider temporal diversification effects for a more realistic assessment of the relation between yield volatility and crop diversity and test the relationship in other regions and production conditions.

Policy sequencing can increase public support for ambitious climate policy

Abstract Public support for ambitious climate policies and carbon prices that have direct costs for voters may depend on policy sequencing. Policy sequencing theory suggests that the strategic ordering of policies into sequences that initially create benefits can subsequently increase support for higher carbon prices. However, systematic quantitative evidence about the effects of sequencing on public support is lacking. We provide novel theoretical and empirical insights on the mechanisms through which strategic policy sequencing affects public support for climate policies. We generated these insights using geospatial data and a representative conjoint experiment with Swiss voters conducted just before the popular vote on an amendment to the Federal Act on the Reduction of Greenhouse Gas Emissions in June 2021. Our evidence shows that the perceived effectiveness of prior policy-induced benefits is related to more public support for higher carbon prices across sectors. Moreover, we find that more opportunity structures for low-emission alternatives—like higher EV charging station density—are associated with increased public support for carbon prices in the sector where the former material benefits occur. Our results also imply that positive policy perceptions of prior climate policies are related to increased support, particularly among conservative voters and those who do not regard climate change as a salient issue. Thus, strategic policy sequencing could be an effective strategy for broadening public support for ambitious climate policies.

Influence of blood flow restriction training on the aerobic capacity: a systematic review and meta-analysis

Background: Blood flow restriction training (also known as KAATSU training) uses professional equipment to apply pressure to the base of the limbs to limit the blood flow at the distal end of the limbs during exercise, thereby stimulating muscle growth and improving muscle strength with a low exercise intensity. This study aimed to conduct a meta-analysis on the effects of blood flow restriction training on aerobic capacity. Methods: A systematic review and quantitative evidence synthesis (QES) was used to examine the effects of blood flow restriction training on the aerobic capacity. A literature search was performed on relevant databases. Search engines used were MEDLINE, EMBASE, PubMed, Web of Science, SPORT-Discus, CINHAL, ScienceDirect, and the Cochrane Library. Search terms were KAATSU training, blood flow restriction training, and occlusion training. Thirteen articles (a total sample size of 246 participants) fulfilled the inclusion criteria and were included. Results: Blood flow restriction training promoted the improvement in aerobic capacity (standard mean difference (SMD) = 0.40, 95% confidence interval (CI) (0.14–0.66), I2 = 0%, p < 0.01), showing no publication bias. In subgroup analysis, intervention methods, and intervention frequencies had different effects on aerobic capacity. Conclusions: Blood flow restriction training, which is a low intensity exercise, significantly affected aerobic capacity. Twelve blood flow restriction training sessions a week achieved significantly better results than a frequency of two to four training sessions per week. A daily blood flow restriction training session of 6 to 30 min significantly improved aerobic capacity.

The economics of the Manila Galleon

PurposeThis paper aims to offer a unified economic interpretation of the existing evidence on the Manila Galleon. It intends to be an introduction to the Manila Galleon for economists curious about long-term patterns in global trade, but who are not experts on economic history.Design/methodology/approachThe paper jointly presents quantitative and qualitative data to analyze in a critical way the existing work on the Manila Galleon. It proposes a conceptual model from the world-systems approach to reflect on the impact of this trade route. Evidence from two case studies, New Granada and Korea, accompany the model.FindingsThe paper finds that the Manila Galleon was only possible because of the temporary coincidence of a quite singular set of international circumstances and favorable local market conditions. The paper also finds that, despite its large effects on the global integration of silver markets, the Manila Galleon was a profoundly asymmetric activity that brought minor consequences to most of the world.Research limitations/implicationsThis paper shows the importance of additional studies providing systematic quantitative evidence on the Manila Galleon. The long tradition of an archival collection developed by historians offers a huge potential to this line of research. In addition, studies in regions different from Mexico, the Philippines, Spain and China would contribute to a better understanding of the Manila Galleon’s global consequences.Practical implicationsThis paper provides a series of reflections useful to think about the future challenges of global trade. These challenges require understanding the transformations that will come from profound technological change, massive reconfigurations of the geopolitical order and transitions in the long-term cycles of commodities. Because of their rare occurrence, these are forces hardly visible in recent history, making it necessary for the existence of long-term points of reference such as the Manila Galleon.Originality/valueThis paper brings together widespread evidence on the Manila Galleon and provides a unified interpretation of it. This opens the door for audiences who are not experts on the economic history of the period to discuss the topic, allowing them to reflect on its lessons for the modern world.

Falling living standards during the COVID-19 crisis: Quantitative evidence from nine developing countries.

Despite numerous journalistic accounts, systematic quantitative evidence on economic conditions during the ongoing COVID-19 pandemic remains scarce for most low- and middle-income countries, partly due to limitations of official economic statistics in environments with large informal sectors and subsistence agriculture. We assemble evidence from over 30,000 respondents in 16 original household surveys from nine countries in Africa (Burkina Faso, Ghana, Kenya, Rwanda, Sierra Leone), Asia (Bangladesh, Nepal, Philippines), and Latin America (Colombia). We document declines in employment and income in all settings beginning March 2020. The share of households experiencing an income drop ranges from 8 to 87% (median, 68%). Household coping strategies and government assistance were insufficient to sustain precrisis living standards, resulting in widespread food insecurity and dire economic conditions even 3 months into the crisis. We discuss promising policy responses and speculate about the risk of persistent adverse effects, especially among children and other vulnerable groups.

Predictive Effect of Helicobacter pylori in Gastric Carcinoma Development: Systematic Review and Quantitative Evidence Synthesis

Helicobacter pylori (H. pylori) is a bacterial pathogen implicated in gastritis, gastric ulceration, and gastric carcinoma. This study aimed to synthesize literature in providing evidence on the causative role of H. pylori in gastric carcinoma development. This study is based on assessing public literature using an applied meta-analysis, namely, quantitative evidence synthesis (QES). The analytic procedure uses DerSimonian-Laird, including assessing heterogeneity. The QES also utilizes meta-regression and the environmental effect associated with H. pylori in gastric cancer development. Eighteen studies are included in the QES. There is increased prevalence of H. pylori exposure among the cases. The heterogeneity between the CES and individual effect sizes is also significant. Despite controlling for the confoundings, there is increased exposure to H. pylori among the gastric cancer cases, regardless of the differences in the geographic location. H. pylori in this synthesized literature illustrates the contributory role of this microbe in gastric carcinoma. Additionally, regardless of geographic locale, namely, South Korea or Spain, H. pylori is implicated in gastric cancer development.

Sanctions for Intimate Partner Sexual Violence: Is the Law on the Books the Law in Action?

Intimate partner sexual violence (IPSV) is common, yet in many jurisdictions the law still does not adequately recognize it. In those jurisdictions that have formally criminalized IPSV, little is known about the extent to which IPSV-related law on the books is implemented in practice. Especially scarce is systematic quantitative evidence on the processing of IPSV cases by the justice system. We investigate unique case-level court data on the processing and sanctioning of violent sex crime cases in Belgium, a jurisdiction where the law adequately criminalizes IPSV, but where criminal judges are afforded broad sentencing discretion. Our data allow us to observe both the conviction and the sentencing decision. Consequently, we are able to address the endogenous sample selection concerns that arise in the assessment of IPSV-related sentencing disparities by estimating a full-fledged sample selection model. Upon inclusion of a broad range of defendant, victim, and other case controls, we show that defendants who are the victims' spouses or partners receive statistically significantly shorter prison sentences than defendants who are unrelated to the victims, in the sense that they are neither the victims' current or former spouses nor family. The documented extralegal disparity is quantitatively noteworthy and survives a series of robustness checks as well as alternative model specifications. Our analysis thus lends empirical credibility to the perspective that while national legislatures have often been slow to address IPSV, the justice systems may be even slower at internalizing the corresponding law. Our evidence-based insight into de facto legal responses to IPSV is of direct relevance to many jurisdictions globally.

Thresholds for ecological responses to global change do not emerge from empirical data.

To understand ecosystem responses to anthropogenic global change, a prevailing framework is the definition of threshold levels of pressure, above which response magnitudes and their variances increase disproportionately. However, we lack systematic quantitative evidence as to whether empirical data allow definition of such thresholds. Here, we summarize 36 meta-analyses measuring more than 4,600 global change impacts on natural communities. We find that threshold transgressions were rarely detectable, either within or across meta-analyses. Instead, ecological responses were characterized mostly by progressively increasing magnitude and variance when pressure increased. Sensitivity analyses with modelled data revealed that minor variances in the response are sufficient to preclude the detection of thresholds from data, even if they are present. The simulations reinforced our contention that global change biology needs to abandon the general expectation that system properties allow defining thresholds as a way to manage nature under global change. Rather, highly variable responses, even under weak pressures, suggest that 'safe-operating spaces' are unlikely to be quantifiable.

Mapping road traffic crash hotspots using GIS-based methods: A case study of Muscat Governorate in the Sultanate of Oman

Objective:Road traffic crashes (RTCs) are a major global public health problem and cause substantial burden on national economy and healthcare. There is little systematic understanding of the geography of RTCs and the spatial correlations of RTCs in the Middle-East region, particularly in Oman where RTCs are the leading cause of disability-adjusted life years lost. The overarching goal of this paper is to evaluate the spatial and temporal dimensions, identifying the high risk areas or hot-zones where RTCs are more frequent, using the geocoded data from the Muscat governorate. Data:This study is based on data drawn from the Royal Oman Police (ROP) sample iMAAP database and the National Road Traffic Crash (NRTC) database, managed by the ROP and made available for research use by The Research Council of the Sultanate of Oman. The data covered the period from 1st January 2010 to 2nd November 2014. Only RTCs occurred in Muscat Governorate were included in the study. The study is based on 12,438 registered incidents, however, due to disconnections found on road network, RTCs occurred on disconnected parts were removed and the final analysis considered only 9,357 incidents. Methods:We considered an adjacency network analysis integrating GIS and RTC data using robust estimation techniques including: Kernel Density Estimation (KDE) of both 1-D and 2-D space dimensions, Network-based Nearest Neighbour Distance (Net-NND), Network-based K-Function, Random Forest Algorithm (RF) and spatiotemporal Hot-zone analysis. Findings:The analysis highlight evidence of spatial clustering and recurrence of RTC hot-zones on long roads demarcated by intersections and roundabouts in Muscat. The findings confirm that road intersections elevate the risk of RTCs than other effects attributed to road geometry features. The results from GIS application of NRTC data are validated using the sample data generated by iMAAP database. Conclusion:The findings of this study provide statistical evidence and confirm our research hypothesis that road intersections (roundabouts, crosses and bridges) represent higher risk of causing RTCs than other road geometric features. The results also demonstrate systematic quantitative evidence of spatio-temporal patterns associated with the crash risk over different locations on road networks in Muscat. More importantly, the findings clearly pinpoint the importance and influence of the road and traffic related features in road crash spatial analysis.

Neither crowding in nor out: Public direct investment mobilising private investment into renewable electricity projects

Rapid structural change towards a low-carbon energy supply requires significant additional investments into innovative but high-risk low-carbon technologies. Mobilising greater private investments requires applying the right policy instruments, but while fiscal measures and regulation have been well researched, systematic quantitative evidence about the effect of public direct investment is lacking. Absent empirical evidence, contradictory theoretical arguments claim that such public (co-)investments either ‘crowd out’ or ‘crowd in’ private investors. In this paper we show that the macroeconomic concept of crowding out/in is inapplicable to sectoral studies such as of renewable electricity. Instead, both neoclassical microeconomics and evolutionary economics suggest public direct investment to have a positive effect due to either externalities or market creation effects. We also provide the first quantitative estimate of the effect of public direct investment on private investment into renewable electricity technologies for 17 countries in the period 2004–2014. Using FGLS and static and dynamic GMM estimators, we find that public investments not only have a positive but also consistently the largest effect on private investment flows relative to feed-in tariffs, taxes and renewable portfolio standards in general, and for wind and solar technologies separately. Implications for policy aimed at accelerating the low-carbon transition are discussed.

DNA Methylation of Candidate Genes (ACE II, IFN-γ, AGTR 1, CKG, ADD1, SCNN1B and TLR2) in Essential Hypertension: A Systematic Review and Quantitative Evidence Synthesis.

Physical, chemical, and social environments adversely affect the molecular process and results in cell signal transduction and the subsequent transcription factor dysregulation, leading to impaired gene expression and abnormal protein synthesis. Stressful environments such as social adversity, isolation, sustained social threats, physical inactivity, and highly methylated diets predispose individuals to molecular level alterations such as aberrant epigenomic modulations that affect homeostasis and hemodynamics. With cardiovascular disease as the leading cause of mortality in the US and blacks/African Americans being disproportionately affected by hypertension (HTN) which contributes substantially to these deaths, reflecting the excess mortality and survival disadvantage of this sub-population relative to whites, understanding the molecular events, including epigenomic and socio-epigenomic modulations, is relevant to narrowing the black-white mortality risk differences. We aimed to synthesize epigenomic findings in HTN namely (a) angiotensin-converting enzyme 2 (ACE II) gene, (b) Toll-like receptor 2 (TLR2) gene, (c) interferon γ (IFN-γ) gene, and (d) Capping Actin Protein, Gelosin-Like (CAPG) gene, adducin 1(ADD1) gene, (e) Tissue inhibitor of metalloproteinase 3 (TIMP3), (f) mesoderm specific transcript (MEST) loci, (g) sodium channel epithelial 1 alpha subunit 2 (SCNN1B), (h) glucokinase (CKG) gene (i) angiotensin II receptor, type1 (AGTR1), and DNA methylation (mDNA). A systematic review and quantitative evidence synthesis (QES) was conducted using Google Scholar and PubMed with relevant search terms. Data were extracted from studies on: (a) Epigenomic modulations in HTN based on ACE II (b) TLR2, (c) IFN-γ gene, (d) CAPG, ADD1, TIMP3, MEST loci, and mDNA. The random-effect meta-analysis method was used for a pooled estimate of the common effect size, while z statistic and I^2 were used for the homogeneity of the common effect size and between studies on heterogeneity respectively. Of the 642 studies identified, five examined hypermethylation while seven studies assessed hypomethylation in association with HTN. The hypermethylation of ACE II, SCNN1B, CKG, IFN-γ gene, and miR-510 promoter were associated with hypertension, the common effect size (CES) = 6.0%, 95% CI, −0.002–11.26. In addition, the hypomethylation of TLR2, IFN-γ gene, ADD1, AGTR1, and GCK correlated with hypertension, the CES = 2.3%, 95% CI, −2.51–7.07. The aberrant epigenomic modulation of ACE II, TLR2, IFN-γ, AGTR1, and GCK correlated with essential HTN. Transforming the environments resulting from these epigenomic lesions will facilitate early intervention mapping in reducing HTN in the US population, especially among socially disadvantaged individuals, particularly racial/ethnic minorities.

Aberrant Epigenomic Modulation of Glucocorticoid Receptor Gene (NR3C1) in Early Life Stress and Major Depressive Disorder Correlation: Systematic Review and Quantitative Evidence Synthesis.

Early life stress (ELS) induced by psychological trauma, child maltreatment, maternal separation, and domestic violence predisposes to psycho-behavioral pathologies during adulthood, namely major depressive disorder (MDD), anxiety, and bipolar affective disorder. While environmental data are available in illustrating this association, data remain to be established on the epigenomic underpinning of the nexus between ELS and MDD predisposition. Specifically, despite the observed aberrant epigenomic modulation of the NR3C1, a glucocorticoid receptor gene, in early social adversity and social threats in animal and human models, reliable scientific data for intervention mapping in reducing social adversity and improving human health is required. We sought to synthesize the findings of studies evaluating (a) epigenomic modulations, mainly DNA methylation resulting in MDD following ELS, (b) epigenomic modifications associated with ELS, and (c) epigenomic alterations associated with MDD. A systematic review and quantitative evidence synthesis (QES) were utilized with the random effect meta-analytic procedure. The search strategy involved both the PubMed and hand search of relevant references. Of the 1534 studies identified through electronic search, 592 studies were screened, 11 met the eligibility criteria for inclusion in the QES, and 5 examined ELS and MDD; 4 studies assessed epigenomic modulation and ELS, while 2 studies examined epigenomic modulations and MDD. The dense DNA methylation of the 1F exon of the NR3C1, implying the hypermethylated region of the glucocorticoid receptor gene, was observed in the nexus between ELS and MDD, common effect size (CES) = 14.96, 95%CI, 10.06–19.85. With respect to epigenomic modulation associated with child ELS, hypermethylation was observed, CES = 23.2%, 95%CI, 8.00–38.48. In addition, marginal epigenomic alteration was indicated in MDD, where hypermethylation was associated with increased risk of MDD, CES = 2.12%, 95%CI, −0.63–4.86. Substantial evidence supports the implication of NR3C1 and environmental interaction, mainly DNA methylation, in the predisposition to MDD following ELS. This QES further supports aberrant epigenomic modulation identified in ELS as well as major depressive episodes involving dysfunctional glucocorticoid-mediated negative feedback as a result of allostatic overload. These findings recommend prospective investigation of social adversity and its predisposition to the MDD epidemic via aberrant epigenomic modulation. Such data will facilitate early intervention mapping in reducing MDD in the United States population.

Does Scientific Progress Affect Culture? A Digital Text Analysis

We focus on a unique episode in the history of science, the elaboration of the theory of evolution by Charles Darwin, to study the interplay between scientific progress and cultural change. We perform text analysis on a corpus of hundreds of thousands of books, with the use of techniques from machine learning. We examine, in particular, the diffusion of certain key ideas of the theory of evolution in the broader cultural discourse and imaginary. We find that some concepts in Darwin’s theory, such as Evolution, Survival, Natural Selection and Competition, diffused in the cultural discourse immediately after the publication of On the Origins of Species. Other concepts such as Selection and Adaptation were already present in the cultural dialogue. Moreover, we document semantic changes for most of these concepts over time, and a more positive sentiment toward these ideas, thus providing further insights about the channels through which Darwin’s theory influenced the broader discourse. Our findings provide the first large-sample, systematic quantitative evidence of the relation between two key factors of long-term economic growth (science and culture), and suggest that machine learning and natural language processing offer promising tools to explore this relation. Institutional subscribers to the NBER working paper series, and residents of developing countries may download this paper without additional charge at www.nber.org.

Invited Commentary Related to: Treatment Options for Nonunion With Segmental Bone Defects: Systematic Review and Quantitative Evidence Synthesis.

Invited Commentary Related to: Treatment Options for Nonunion With Segmental Bone Defects: Systematic Review and Quantitative Evidence Synthesis.

Treatment Options for Nonunion With Segmental Bone Defects: Systematic Review and Quantitative Evidence Synthesis.

To determine which reconstruction treatment of long bones nonunion with segmental bone defects (SBDs) is effective to restore bone length and union with good function. PubMed was used to identify published literature on treatment of SBD caused by fracture nonunion regardless of infection between January 1975 and December 2014. We included retrospective cohort studies with a minimum sample size of 10 consecutive patients with minimum follow-up of 18 months and available data on radiographic and functional outcomes. Literature review revealed 24 publications with a sample size of 504 patients (395 males, 109 females). Data on bone union and functional outcome and complications were collected and analyzed based on validated classification systems. Two outcome groups were categorized for bone union and functional outcome, success, and failure. We then performed heterogeneity test to examine the variability or differences in the methods used by these studies and based on that we determined whether the fixed effect or random effect method is appropriate in examining the summary or pool estimate. Pool estimate was examined for bone union and functional outcome in each surgical modality and in each anatomic location when data were available. Treatment of SBD can be challenging. This quantitative evidence synthesis shows that bone union was achieved by different procedures with variable bone union and functional outcomes. Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Unequal Property Rights: A Study of Land Right Inequalities in Rwanda

Most measures of inequality focus on the distribution of income and resources. A potentially important additional source of inequality stems from unequal property rights protection. The aim of the present paper was to examine the existence and patterns of systematic within-country inequalities in effective land rights in Rwanda. While a large qualitative literature discusses the comparative land rights of different groups, there is a lack of systematic quantitative evidence on the existence of land right inequalities. The results of estimations drawing on data on the land tenure arrangements of over 17 000 Rwandan households do indeed suggest within-country inequalities in land rights. In particular, despite recent reform efforts to improve women's land rights, a gender gap in land rights was observed that persisted throughout the 2005–2011 period studied, highlighting that institutional development takes time and that changes in de jure legislation do not automatically translate into changes in effective rights. Moreover, conflict-displaced households and households resettled to newly constructed village settlements all report weaker land rights than their respective comparison groups.

Update on the American College of Rheumatology/Spondyloarthritis Research and Treatment Network/Spondylitis Association of America axial spondyloarhtritis treatment guidelines project.

The American College of Rheumatology, the Spondyloarthritis Research and Treatment Network, and the Spondylitis Association of America have begun collaborating on a project to develop treatment guidelines for axial spondyloarthritis. The project will use the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) method, which is based on systematic literature reviews and quantitative evidence summaries, to develop treatment recommendations for the use of pharmacological interventions, rehabilitation, surgery, preventive care, and disease monitoring in patients with ankylosing spondylitis and axial spondyloarthritis.

Differences in work values: understanding the role of intra- versus inter-country variation

A growing literature emphasizes the need for studies taking a contingency perspective to international HRM to move beyond mean country differences in work values and begin considering intra-country variation (ICV). We use individual-level data on Hofstedeian values – not hitherto available – to infuse this literature with systematic quantitative evidence regarding the importance of ICV vis-à-vis inter- or between-country variation. We begin by estimating various random effects models, discovering that ICV accounts for the bulk, approximately 85%, of total variation in work values. To add a much-lacking comparative dimension and because ICV only has real-life relevance if we know its sources and can observe them, a three-level multilevel analysis provides a novel disentanglement of the importance of country relative to region and socioeconomic stratum as readily observable within-country sources of variation in values. Results show the value for practitioners and scholars of not only focusing on country differences strictly but also considering subnational categorizations when seeking to understand differences in work values. Key contribution of this paper is to take the debate on ICV out of the theoretical and into the practical realm. Implications of our findings are discussed.

Terrorist and Non-Terrorist Criminal Attacks by Radical Environmental and Animal Rights Groups in the United States, 1970–2007

Despite concerns about the growing threat posed by domestic radical environmental and animal rights groups to the United States, there has been little systematic quantitative evidence depicting the characteristics of their attacks over time. In this paper we analyze data on 1,069 criminal incidents perpetrated by environmental and animal rights extremists from 1970 to 2007. Based on the Global Terrorism Database's definition of terrorism, we classified 17 percent of these incidents as terrorist. To supplement the analysis, we also conducted interviews with a nonrandom sample of twenty-five activists who self-identified as part of the environmental or animal rights movements. We find that overall, the attacks staged by radical environmental and animal rights groups thus far have been overwhelmingly aimed at causing property damage rather than injuring or killing humans. Further, results from our interviews suggest that activists appear to weigh carefully the costs and benefits of illegal protest. Despite the fact that attacks by environmental and animal rights groups have thus far been almost universally nonviolent, concerns linger that this situation might change in the future.

What should be said to the lay public regarding ADHD etiology based on unbiased systematic quantitative empirical evidence

What Should Be Said to the Lay Public Regarding ADHD Etiology Based on Unbiased Systematic Quantitative Empirical Evidence Samuele Cortese,* Stephen V. Faraone, and Joseph Sergeant Institute for Pediatric Neuroscience, New York University Child Study Center, New York City, New York Department of Psychiatry and of Neuroscience and Physiology, State University of New York Upstate Medical University, Syracuse, New York Vrije Universiteit, Amsterdam, Netherlands