Synthetic Control Research Articles

Munich’s selective diesel vehicle ban and its impact on nitrogen dioxide concentrations: A quasi-experimental study

BackgroundThe current limit on NO2 concentrations of 40 μg/m3, set by the European Union, has been regularly exceeded in Munich, Germany. This limit will likely be reduced towards the WHO recommended target of 10 μg/m3. Against this backdrop, the city implemented a selective diesel vehicle ban within the existing low-emission zone in February 2023, targeting Euro 4 and older diesel vehicles. Our study investigated the effect of Munich’s selective diesel vehicle ban on NO2 concentrations, focusing on the half-year period following its implementation. MethodsOur study utilized a synthetic control approach (primary analysis) and a controlled interrupted time series approach (secondary analysis). These quasi-experimental methodologies create a ‘counterfactual’ no-intervention scenario, enabling comparison between observed and counterfactual scenarios to estimate an intervention effect. We employed historical controls, using routine data from multiple monitoring stations located within and outside the low-emission zone for 2014 to 2022, and considered possible confounders. ResultsNO2 concentrations within Munich’s low-emission zone showed overall declining trends from August 2014 to July 2023. Effects of the selective diesel vehicle ban were small and wide confidence intervals indicate large uncertainty in the magnitude and direction of the effect. At Landshuter Allee, the average intervention effect was −2.67 μg/m3 (95 %-CI = [-12.72; 7.38]), at Stachus it was −2.74 μg/m3 (95 %-CI = [-9.91; 4.42]), and at Lothstrasse it was −1.03 μg/m3 (95 %-CI = [-7.75; 5.69]). The secondary analysis confirmed these findings, reinforcing uncertainty about the effect of the intervention. ConclusionOur study suggests that Munich’s selective diesel vehicle ban had a limited effect on lowering NO2 concentrations. Possible explanations include the ban’s focus on Euro 4 and older diesel vehicles, many exemptions to the selective ban, and unclear enforcement. This highlights that comprehensive approaches and ongoing, well-designed monitoring and evaluation are crucial for addressing urban air pollution and protecting public health.

Photocatalysis with Covalent Organic Frameworks.

ConspectusUtilizing light to enable chemical conversions presents a green and sustainable approach to produce fuels and chemicals, and photocatalysis is one of the key chemical technologies that needs to be well developed in this century. Despite continuous progress in the advancement of various photocatalysts based on small inorganic and organic compounds, polymers, and networks, designing and constructing photocatalysts that combine activity, selectivity, and reusability remains a challenging goal. For catalytic activity, the difficulty originates from the complexity of photochemical reactions, where the light-harvesting system, multielectron and multihole-involving processes, and pinpoint mass delivery simultaneously need to be established in the system. For selectivity, the difficulty stems from the elaborate design of catalytic sites and space, especially their orbital energy levels, spatial arrangement, and environment; developing a molecular strategy that enables an overall design and control of these factors of different aspects is necessary yet arduous. For reusability, the difficulty arises from the stability and recyclability of the photocatalysts upon continuous operation under photoredox reaction conditions. How to recover photocatalysts in an energy-saving way to enable their cyclic use while retaining activity and selectivity is at the core of this problem. These bottleneck issues reflect that molecular design of a photocatalyst is not a simple summation of the above requirements, but a systematic scheme that can organically interlock various aspects is needed.To enable such an elaborate design and precise control, a basic requirement of the scaffold for constructing a promising photocatalyst is that its primary and high-order structures should be molecularly predesignable and synthetically controllable. Such a molecular regime has successfully evolved in natural photosynthesis, where light-harvesting chlorophyll antennae and photocatalytic centers are spatially well-organized and energetically well-defined to build ways for exciton migration, photoinduced electron transfer and charge separation, electron and hole flows, and oxidation of water and reduction of carbon dioxide, thereby converting water into oxygen to release ATP and NADPH via the light reaction and carbon dioxide into glucose with ATP and NADPH through the dark reaction. Similarly, a predesignable polymeric scaffold would be promising for integrating these complex photochemical processes to construct photocatalysts.Covalent organic frameworks (COFs) are a class of extended yet polymeric materials that enable the organization of organic units or metallo-organic moieties into well-defined architectures. In principle, COFs are molecularly designable with topology diagrams and synthetically controllable through polymerization reactions, offering an irreplaceable platform for designing and synthesizing photocatalysts. This feature enticed researchers to develop various photocatalysts based on COFs and drove the rapid progress in this field over the past decade. In this Account, we summarize the recent advances in the molecular design and synthetic control of COF photocatalysts, by highlighting the key achievements in developing ways to enable light harvesting, trigger photoinduced electron transfer and charge separation, allow charge carrier transport and mass delivery, control energy level, catalytic space, and environmental engineering, and develop stability and recyclability with an aim to reveal a full picture of this field. By scrutinizing typical photocatalytic reactions, we show the key problems to be addressed for COFs and predict future directions.

Are there lasting impacts of China’s anti-poverty program? A synthetic control analysis

ABSTRACT China’s National Poor Counties (NPCs) program represents one of the largest anti-poverty efforts ever undertaken in a developing country. In spite of this, no causal analysis has been undertaken to examine whether regions in poverty at the end of the program actually achieve sustainable growth after support is removed. This paper provides the first long-term analysis of China’s NPCs (National Poor Counties) program on local development, investigating whether poor regions continue to develop economically after exiting the anti-poverty program. Focusing on the period 1986 to 2010, I construct plausible counterfactuals for counties that participated and graduated from the NPCs registry using the synthetic control method. This exercise reveals several new insights. First, on average, graduates of China’s anti-poverty program exhibit roughly the same growth outcomes as those still receiving support from the program. Second, I show that focusing on the average impact masks sizable heterogeneity when disaggregating to a case by case analysis of counties. Importantly, for the subset of counties which graduated from the first wave of the poverty reduction program in 1993, there is a demonstrably faster expansion post-graduation. For more recent county’s graduating from the program, however, I find significantly lower income growth of NPCs program completion in the long run.

Evaluation of the carbon reduction effect of China’s low-carbon pilot policy based on synthetic control method

Evaluation of the carbon reduction effect of China’s low-carbon pilot policy based on synthetic control method

Aviation Discontinuity and Regional House Prices: A Quasi-Experiment in New Zealand

Although there is evidence that more regional airport activities can increase regional house prices, no study has examined the relevant impacts of aviation discontinuity. My unique quasi-experiment data comes from New Zealand where Jetstar withdrew its domestic services from four airports/regions in December 2019. The synthetic control method (SCM)'s results reveal that the withdrawal created different impacts on the house prices of the regions involved, in which the overall effect was negative in the short run but the housing market in New Zealand has recovered in the long run.

A-238 Lyophilized Bead Multiplex Assays for CT/NG/TV Detection

Abstract Background Chlamydia trachomatis (CT), Neisseria gonorrhoeae (NG), and Trichomonas vaginalis (TV) cause the three most prevalent sexually transmitted infectious diseases in developed countries, contributing to approximately 300 million new infections worldwide, annually. Due to the challenges of culturing and using immunoassays to detect these pathogens, DNA-based molecular tests have been instrumental, and current trends in molecular testing for CT/NG/TV have moved toward point-of-care tests. Lyophilization provides benefits required for point-of-care tests, such as ambient storage, extended shelf life, simplified downstream workflow, and variable formats. A lyophilized-bead format enables an assay to be placed in sealed consumables and stored at room temperature for up to two years. An additional consideration is the need for endogenous and exogenous controls. Exogenous in-process controls can be used to validate the performance of workflows culminating in a qPCR reaction and provide flexibility to test developers. An ideal exogenous in-process control is nonhomologous to human or human pathogen genome sequences and does not align with primers or probes designed for pathogen detection. The objective of the current study was to develop a lyophilized-bead-format assay containing an ideal exogenous control and establish whether it is a valid option for the accurate detection of CT, NG, and TV. Methods A synthetic DNA control containing targets for CT/NG/TV/RNase P (RP)/exogenous control was used to establish an analytical LOD by qPCR. The 5-plex assay, lyophilized in beads, was hydrated and tested for linearity over an 8-log range of the synthetic DNA control. Further, the qPCR lyophilized bead with assay was tested with a proficiency sample by extracting DNA from ZeptoMetrix NATtrol CT/NG/TV Positive Control and spiking-in the exogenous DNA control. qPCR was performed on the extracted DNA and human cDNA. Results The analytical LOD for the control DNA was determined to be 5 copies/reaction. Additionally, linearity was observed by qPCR over an 8-log range of the synthetic DNA control for all five targets in multiplex with good efficiencies and R2 values. Finally, all targets were amplified and detected by qPCR using DNA extracted from ZeptoMetrix NATtrol CT/NG/TV Positive Control with spiked-in exogenous DNA control. The detection of the exogenous sequence in the qPCR multiplex reaction indicated the extraction was successful. Conclusions We have developed a multiplex qPCR assay in lyophilized-bead format that can identify infectious agents, such as CT/NG/TV, in a single reaction. We have included RP as a human host control, plus an exogenous in-process control, for a total of 5-plex in separate fluorescent channels. We have shown that our lyophilized beads with assay produce a positive qPCR result when combined with a proficiency sample.

Resonance Effects from Substituents on L-Type Ligands Mediate Synthetic Control of Gold Nanocluster Frontier Orbital Energies.

The ligands of metal nanoclusters can be used to control their properties and reactivity, but a framework guiding their use remains elusive. Hammett studies of Au8(PPh3)72+ and Au9(PPh3)83+ nanoclusters with para- and meta-methyl and -methoxy groups indicate that resonance effects, not inductive effects, yield quantitative shifts of the HOMO-LUMO transitions involving orbitals local to the cluster core. Individual ligand exchanges reveal that these shifts are caused by only four of seven ligands, inconsistent with inductive effects. Quantum chemical calculations predict no trend in Au atom charges with respect to Hammett parameter but do predict bond length trends expected for a resonance structure that includes the Au atoms. Computed orbitals show contributions from specific para-OMe oxygen lone pairs to the HOMO, indicating delocalization from the core to specific ligands. These results suggest that resonance structures could be drawn including Au and ligands, guiding efforts to modulate nanocluster electronic structure and energy transfer.

The feasibility of flexible and adaptive green certification in accelerating zero carbon cities

This research measures the feasibility of using a flexible and adaptative green certification in accelerating the transition toward zero carbon cities. Thus, the EDGE program, a web-based application, is used to evaluate its influence on the number of LEED program certifications in the countries where this web-based application program is applied. A panel dataset of yearly LEED and EDGE-certified buildings numbers is created, and a synthetic control method is implemented for the top five countries for EDGE-certified projects. Counterfactuals are constructed to mimic the number of LEED-certified buildings in a treated country using controls based on countries where no EDGE program is recorded. It can be concluded that the establishment of an EDGE program causes a significant decrease in the number of LEED-certified buildings, especially in Colombia, Mexico, and Peru. The result remains robust when performing several robustness analyses. Analysis does not mean that the LEED will be replaced by the EDGE, but that a significant number of new certifications would change over the coming years. While many studies discussed the barriers for the adoption of green certifications, this research highlights the necessity of directing more research to keep up with updated smart tools and applications to increase the proliferation of the green certifications.

Does emission trading system (ETS) deserve further promotion in the building sector? Evidence from China

Although the emission trading system (ETS) has been widely applied and recognized in energy-production side, its impact on the energy-demand side is still ambiguous. Does ETS deserve promotion in energy-demand sectors? If so, what preparations are necessary? In response to these pressing but highly publicized issues, this paper, for the first time, focuses on the building sector which is the most typical energy-demand sector based on energy consumption data from public buildings across 26 regions in China spanning 12 years by employing the Synthetic Control Method (SCM). China, as the most representative developing country with more than ten years of ETS pilot practice for buildings, is a good evidence base. The results indicate that ETS has overall applicability to the building sector despite regional variations. And the government support, industrial structure and economic development orientation are the most determinant of its effect, rather than the conventionally perceived heterogeneous sectoral characteristics of buildings. Moreover, for buildings in the stage of rigid growth, the ETS should be adopted first and foremost to reduce its carbon intensity rather than the total amount. The findings provide practical recommendations on whether and how to promote ETS in future buildings, particularly in developing countries.

Gold Nanorod-Embedded PDMS Micro-Pillar Array for Localized Photothermal Stimulation.

Gold nanorods (GNRs) are one of the most promising biomaterial choices for the photothermal activation of neurons due to their relative biocompatibility, unique photothermal properties, and broad optical tunability through their synthetic shape control. While photothermal stimulation using randomly accumulated GNRs successfully demonstrates the potential treatment of functional neural disorders by modulating the neuronal activities using localized heating, there are limited demonstrations to translate this new concept into large-arrayed neural stimulations. In this paper, we report an arrayed PDMS micropillar platform in which GNRs are embedded as pixel-like, arrayed photothermal stimulators at the tips of the pillars. The proposed platform will be able to localize GNRs at predetermined pillar positions and create thermal stimulations using near-infrared (NIR) light. This will address the limitations of randomly distributed GNR-based approaches. Furthermore, a flexible PDMS pillar structure will create intimate interfaces on target cells. By characterizing the spatiotemporal temperature change in the platform with rhodamine B dye, we have shown that the localized temperature can be optically modulated within 4°C, which is in the range of temperature variation required for neuromodulation using NIR light. We envision that our proposed platform has the potential to be applied as a photothermal, neuronal stimulation interface with high spatiotemporal resolution.

Changes in Healthcare Utilization After the 2022 Seoul Metropolitan Flood: Applying a Generalized Synthetic Control Approach.

Floods can have adverse health effects and impose a burden on healthcare systems. However, the potential consequences of floods on specific medical causes in densely populated metropolitan cities has not been characterized yet. Therefore, we evaluate the changes in healthcare utilization patterns after the 2022 Seoul flood using nationwide health insurance data. Based on the flood inundation map, districts within the flooded municipalities of Seoul were classified as severe-(n=12), mild-(n=22), or non-(n=38) flood-affected districts. Capitalizing on the timing of the flood as a natural experiment, a generalized synthetic control method was applied to estimate changes in the number of disease-specific hospital visits in flood-affected districts during 2weeks after the flood. We found excess hospital visits for external injuries (20.2 visits, 95% CI: -6.0, 45.2) and fewer visits for pregnancy and puerperium (-3.0 visits, 95% CI: -5.1, -0.5) in residents of flooded districts. When comparing severe- and non-flood districts, the increase in hospital visits for external injuries (56.2 visits, 95% CI: 17.2, 93.2) and a decrease in hospital visits related to pregnancy and puerperium (-5.3 visits, 95% CI: -8.4, -1.6) were prominent in residents living in severe-flood affected districts. Disease specific analysis showed an increase in hospital visits for injuries to the elbow and forearm, ankle and foot injuries, and chronic lower respiratory diseases in severe-flood-affected districts. However, these impacts were not observed when comparing the mild- and non-flood-affected districts. Our study suggests an immediate and substantial change in medical demand following flood exposure, highlighting the importance of public health responses after flood events.

The fiscal effects of immigration on local governments: Revisiting the Mariel Boatlift

Immigration raises important political and economic questions, yet there remains considerable disagreement about its short- and long-term consequences. This paper examines the fiscal consequences of immigration for local governments. Previous work has highlighted the gap between the long-term economic benefits of immigration and the short-term fiscal burden posed by recent arrivals, however several influential estimates based on cash-flow accounting suffer from potential bias. I use a quasi-experimental approach to re-examine a famous case: the large wave of Cuban refugees that landed in Miami in 1980, otherwise known as the Mariel Boatlift. Using a synthetic control design, I find that per-pupil education costs increased in Miami in the aftermath of the Boatlift, financed by an increase in state transfers. These effects persisted for at least ten years. The results shed light on the heterogeneous impacts of immigration over time and space.

Nanopore signal deviations from pseudouridine modifications in RNA are sequence-specific: quantification requires dedicated synthetic controls

Chemical modifications to mRNA respond dynamically to environmental cues and are important modulators of gene expression. Nanopore direct RNA sequencing has been applied for assessing the presence of pseudouridine (ψ) modifications through basecalling errors and signal analysis. These approaches strongly depend on the sequence context around the modification, and the occupancies derived from these measurements are not quantitative. In this work, we combine direct RNA sequencing of synthetic RNAs bearing site-specific modifications and supervised machine learning models (ModQuant) to achieve near-analytical, site-specific ψ quantification. Our models demonstrate that the ionic current signal features important for accurate ψ classification are sequence dependent and encompass information extending beyond n + 2 and n − 2 nucleotides from the ψ site. This is contradictory to current models, which assume that accurate ψ classification can be achieved with signal information confined to the 5-nucleotide k-mer window (n + 2 and n − 2 nucleotides from the ψ site). We applied our models to quantitatively profile ψ occupancy in five mRNA sites in datasets from seven human cell lines, demonstrating conserved and variable sites. Our study motivates a wider pipeline that uses ground-truth RNA control sets with site-specific modifications for quantitative profiling of RNA modifications. The ModQuant pipeline and guide are freely available at https://github.com/wanunulab/ModQuant.

Policy evaluation and optimization for photovoltaic poverty alleviation projects in Anhui Province of China

To synergize climate mitigation with poverty alleviation, China has implemented photovoltaic poverty alleviation (PVPA) projects since 2014, with Anhui Province being among the initial pilot regions. However, further exploration is needed to determine the extent to which this policy can improve the economic status of poverty-stricken areas. This study aims to evaluate the effects of PVPA projects in Anhui Province from a macroscopic perspective and via the panel data from 11 poverty-stricken counties, including 5 pilot counties, between 2011 and 2018. By employing the differences-in-differences (DID) model and synthetic control method (SCM) model, this study calculated the treatment effects of the PVPA policy. The analysis revealed that the policy did not significantly increase rural residential income at the county level. The insignificant treatment effects reflect a weak policy implementation. The PVPA policy tries to synergize the energy-climate-poverty nexus, requiring the coordination of various stakeholders and departments. Meanwhile, governance theory highlights the multivariate character of policy and considers the role of multiple social actors. Therefore, it is necessary to explore the governance factors when the policy implementation is weak. Further investigation of the PVPA projects reveals that the main governance challenges include insufficient motivation, information asymmetry, conflicts of interest, renewable energy curtailment, and the absence of proper maintenance and benefit distribution mechanisms. Considering the principles of good governance, recommendations for enhancing the effectiveness of the PVPA policy are proposed.

Luminescent Organic Triplet Diradicals as Optically Addressable Molecular Qubits.

Optical-spin interfaces that enable the photoinitialization, coherent microwave manipulation, and optical read-out of ground state spins have been studied extensively in solid-state defects such as diamond nitrogen vacancy (NV) centers and are promising for quantum information science applications. Molecular quantum bits (qubits) offer many advantages over solid-state spin centers through synthetic control of their optical and spin properties and their scalability into well-defined multiqubit arrays. In this work, we report an optical-spin interface in an organic molecular qubit consisting of two luminescent tris(2,4,6-trichlorophenyl)methyl (TTM) radicals connected via the meta-positions of a phenyl linker. The triplet ground state of this system can be photoinitialized in its |T0⟩ state by shelving triplet populations as singlets through spin-selective excited-state intersystem crossing with 80% selectivity from |T+⟩ and |T-⟩. The fluorescence intensity in the triplet manifold is determined by the ground-state polarization, and we show successful optical read-out of the ground-state spin following microwave manipulations by fluorescence-detected magnetic resonance spectroscopy. At 85 K, the lifetime of the polarized ground state is 45 ± 3 μs, and the ground state phase memory time is Tm = 5.9 ± 0.1 μs, which increases to 26.8 ± 1.6 μs at 5 K. These results show that luminescent diradicals with triplet ground states can serve as optically addressable molecular qubits with long spin coherence times, which marks an important step toward the rational design of spin-optical interfaces in organic materials.

A Two-Stage Evaluation of China’s New Energy Industrial Policy Package

Energy structural transformation plays a strategically important role in achieving the dual-carbon reduction goals. Among the various approaches to carbon reduction, the Chinese government regards the growth of the new energy industry as an essential means. Considering that the government policy support determines the long-term growth of the new energy industry, how to improve and optimize the policy support system has always been the core issue. Based on the fact that policy evaluation is a prerequisite, and the new energy industrial development requires the government to promote solutions in the form of a policy package rather than just individual policies, we investigate whether the implementation of the new energy industry policy package (NEIPP) is effective through an empirical case study of Shanghai. A two-stage evaluation method, which integrates the content analysis method (CAM) and synthetic control method (SCM), was used to empirically evaluate the actual effect of the NEIPP. At Stage One, four policy goals were summarized. SCM was used to identify the pure multi-effect of the NEIPP. The results showed that the NEIPP had a significant positive effect on green economic growth and industrial structure, while having a negative effect on carbon emissions. The NEIPP had no impact on the promotion of technological innovation. Several policy implications were drawn from this study.

Increasing intergovernmental coordination to fight crime: evidence from Mexico

Abstract Latin America is the most violent region in the world, with many countries also suffering from high levels of criminality and the presence of powerful criminal organizations. Identifying government responses that improve citizen security is imperative. Existing research argues that improving intergovernmental coordination helps the state combat criminality, but has limited its analysis to political factors that affect coordination. I study the impact of increasing intergovernmental coordination between law enforcement agencies. Using the generalized synthetic control method, original data on the staggered implementation of a police reform that increased intergovernmental police coordination and detailed data on criminal organizations and criminality in Guanajuato, Mexico, I find that the reform weakened criminal organizations and reduced violent crime, but increased violence.

Measuring Price Effects from Disasters Using Public Data: A Case Study of Hurricane Ian

Natural disasters can disrupt housing markets, causing destruction to communities and distress to economic activity. To estimate the effects of disasters on home prices, publicly available data on property damages are often used to classify “treated” properties. However, by design, these data lack precise geospatial information, leading to measurement error in the treatment variable because aggregate measures must be used. We leverage leading difference-in-differences and synthetic control methodologies across various treatments and levels of geography to measure price effects with such data following Hurricane Ian’s unexpected landfall in Southwest Florida during September 2022, coinciding with the state’s initial recovery from the COVID-19 pandemic. Empirical results suggest positive, time-varying price effects, though we place caveats on these results because there may be many mechanisms underway; our results should be interpreted as descriptive correlations and not causal effects for various reasons. Our main contribution is methodological, highlighting the importance of robustness checks, functional form, statistical techniques, and testing across different samples. Additionally, quicker access to high-quality public data could enhance quantitatively informed conversations on natural disaster effects.

The Impact of City-County Mergers: Evidence from Sichuan Province

Municipal mergers are often used to facilitate regional economic development. City-county mergers (CCM) are a form of municipal merger and one of the administrative division adjustment methods adopted by prefecture-level city governments to accelerate regional economic developments in China. Most studies of CCMs have focused on the economic effects of CCMs on prefecture-level cities, and little attention has been paid to the county-level effects post-merger. In this paper, we use the Synthetic Control Method (SCM) to examine the effect of the CCM of Nanxi district (formerly Nanxi county) in Sichuan province. We find that after the CCM, GDP per capita was 1989 yuan higher in 2017 than predicted. We also find that the structure of the local economy was altered toward a more industrialized economy, with a decrease in service and agricultural shares (although only significantly for the industrial and service). There is also evidence that these findings were driven by a larger portion of the local economy that was from private markets, suggesting these reforms incentivized larger private production.

Environmental policies as engines for tourism eco-efficiency: quasi-experimental evidence

Determining the actual effectiveness of environmental policies is paramount for enhancing tourism eco-efficiency. However, few studies have systematically investigated the specific effects of such policies on tourism eco-efficiency. We utilize the slack-based measure data envelopment analysis model to assess tourism eco-efficiency across 30 Chinese provinces from 2003 to 2021. We delve into the environmental policy of China’s Ecological Civilization Pilot Zone, scrutinizing its institutional background and assessing its ramifications for tourism eco-efficiency within the framework of the “Driving forces-Pressure-State-Impact-Response” framework and institutional theory. Moreover, we empirically explore the causal link between this policy and tourism eco- efficiency by adopting the synthetic control and difference-in-differences approaches. Our findings indicate that the implementation of the National Ecological Civilization Pilot Zone policy has led to a 5.16% average enhancement in tourism eco-efficiency. Although significant improvements were observed in Fujian, Jiangxi, and Yunnan, Qinghai experienced a decline, as indicated by the synthetic control method. Furthermore, the impact extends spatially, manifesting both at the local level and as spatial spillover effects on the eco-efficiency of tourism in neighboring regions. These results confirm the policy’s effectiveness and highlight the need for devoting increased attention to economically slower-developing regions in sustainable tourism development.