Synthetic Control Research Articles

Ecological Predictors of Organelle Genome Evolution: Phylogenetic Correlations with Taxonomically Broad, Sparse, Unsystematized Data.

Comparative analysis of variables across phylogenetically linked observations can reveal mechanisms and insights in evolutionary biology. As the taxonomic breadth of the sample of interest increases, challenges of data sparsity, poor phylogenetic resolution, and complicated evolutionary dynamics emerge. Here, we investigate a cross-eukaryotic question where all these problems exist: which organismal ecology features are correlated with gene retention in mitochondrial and chloroplast DNA (organelle DNA or oDNA). Through a wide palette of synthetic control studies, we first characterize the specificity and sensitivity of a collection of parametric and non-parametric phylogenetic comparative approaches to identify relationships in the face of such sparse and awkward datasets. This analysis is not directly focused on oDNA, and so provides generalizable insights into comparative approaches with challenging data. We then combine and curate ecological data coupled to oDNA genome information across eukaryotes, including a new semi-automated approach for gathering data on organismal traits from less systematized open-access resources including encyclopedia articles on species and taxa. The curation process also involved resolving several issues with existing datasets, including enforcing the clade-specificity of several ecological features and fixing incorrect annotations. Combining this unique dataset with our benchmarked comparative approaches, we confirm support for several known links between organismal ecology and organelle gene retention, identify several previously unidentified relationships constituting possible ecological contributors to oDNA genome evolution, and provide support for a recently hypothesized link between environmental demand and oDNA retention. We, with caution, discuss the implications of these findings for organelle evolution and of this pipeline for broad comparative analyses in other fields.

Estimating treatment effect in randomized trial after control to treatment crossover using external controls

ABSTRACT In clinical trials, it is common to design a study that permits the administration of an experimental treatment to participants in the placebo or standard of care group post primary endpoint. This is often seen in the open-label extension phase of a phase III, pivotal study of the new medicine, where the focus is on assessing long-term safety and efficacy. With the availability of external controls, proper estimation and inference of long-term treatment effect during the open-label extension phase in the absence of placebo-controlled patients are now feasible. Within the framework of causal inference, we propose several difference-in-differences (DID) type methods and a synthetic control method (SCM) for the combination of randomized controlled trials and external controls. Our realistic simulation studies demonstrate the desirable performance of the proposed estimators in a variety of practical scenarios. In particular, DID methods outperform SCM and are the recommended methods of choice. An empirical application of the methods is demonstrated through a phase III clinical trial in rare disease.

Direct and spillover effects of a new tramway line on the commercial vitality of peripheral streets: a synthetic-control approach

Abstract In cities, the creation of public transport infrastructure such as light rails can cause changes on a very detailed spatial scale, with different stories unfolding next to each other within the same urban neighbourhood. We study the direct effect of a light rail line built in Florence (Italy) on the retail density of the street where it was built and its spillover effect on other streets in the treated street’s neighbourhood. To this aim, we investigate the use of the synthetic control group (SCG) methods in panel comparative case studies where interference between the treated and the untreated units is plausible, an issue still little researched in the SCG methodological literature. We frame our discussion in the potential outcomes approach. Under a partial interference assumption, we formally define relevant direct and spillover causal effects.

Estimating the return on investment of the New York Tobacco Control Programme: a synthetic control study

ObjectiveTo assess the return on investment (ROI) of the New York Tobacco Control Programme (NY TCP).SettingNew York and other states of the USA.InterventionsNY TCP.OutcomesSmoking prevalence, smoking-attributable healthcare expenditures (SAEs), smoking-attributable...

The effect of key universities on the regional development: empirical evidence from two natural experiments in China

ABSTRACT Universities play a crucial role as anchor institutions in regional development. Using the data from the China City Statistical Yearbook from 1995 to 2011, the synthetic control method was employed to examine the impact of key universities on regional development. Results showed that the expansion of higher education significantly influenced the population density in Xuzhou, and per capita output of secondary industry in both Xuzhou and Dongying; yet it has minimal impact on the per capita GDP and average employee wages of the two cities. Thus, key universities may affect regional development by enhancing the quantity and quality of human capital accumulation rather than directly promoting economic growth.

Overview China's Pilot Free Trade Zone Construction and Economic Globalization

Pilot free trade Zones (PFTZ) are an important strategy of China's opening to the outside world. The construction of pilot free trade zones is a test for actively docking with high- standard international economic and trade rules, and an experiment field for reform and opening- up. Implementing a series of preferential policies in pilot free trade zones, exploring the success and experience, learning the lessons of failure, pilot free trade zones undertake the heavy task of first trial, replication and promotion throughout the countrywide. By September 2020, China had set up 21 pilot free trade zones with 260 innovative achievements. Firstly, this paper discusses the function orientation, development status, existing problems, development countermeasures andpreferential policies of pilot free trade zones. Secondly, it analyzes the influence of the establishment of pilot free trade zones on regional economy, electronic economy and industrial structure. Thirdly, on the base of different theories, the author makes an in- depth analysis of pilot free trade zones. Then DID model, synthetic control method, counterfactual method and other research methods are employed to verify the impact of the establishment of pilot free trade zones. Finally, this paper discusses the impact of the establishment of pilot free trade zones on domestic and international economy froma variety of perspectives. This paper attempts to analyze China's pilot Free trade zonesfrom a variety of perspectives, research methods and dimensions, so that scholars can have a more comprehensive and in-depth understanding of the valuable experience of China's pilot free trades construction, and provide useful reference for the construction of pilot free trade zones in the future.

Synthetic control over the energy transfer and charge transfer between carbon dots and covalent organic framework

Carbon dots (CDs) are environmentally benign, strongly photoluminescent, metal free nanoparticles. Interfacing them with tailor-made organic semiconductors possesing an ordered channel structure such as covalent organic frameworks (COFs) promises to yield multifunctional materials. In this study, microwave-derived CDs are successfully incorporated into the porous structure of COF in a one-pot synthesis in which the condensation reaction between benzo[1,2-b:4,5-b′]dithiophene-2,6-dicarboxaldehyde (BDT) and 1,1,2,2-tetra(p-aminophenyl)ethylene (ETTA) is conducted in the presence of CDs. A detailed structural and optoelectronic characterization of the COF/CDs composite reveals that upon tuning the CDs loadings encapsulated in COF the interaction between both components can be controlled allowing the switch between energy and charge transfer. At CDs loadings ⩽20 wt%, strong binding of CDs to the COF enables charge transfer evinced from the quenched photoluminescence (PL) of both components and accelerated exciton decay kinetics of the COF. At CDs loadings ⩾30 wt% Förster resonance energy transfer from CDs to COF prevails, leading to enhanced COF PL. Our study underlines the interaction mechanism in organic composites and provides the knowledge required for the design of novel functional materials with applications in photocatalysis, optoelectronics and sensing.

Economic and Economic-Statistical Designs of the Synthetic Bayesian Control Chart

Economic and Economic-Statistical Designs of the Synthetic Bayesian Control Chart

Direct potable reuse and birth defects prevalence in Texas: An augmented synthetic control method analysis of data from a population-based birth defects registry.

Direct potable reuse (DPR) involves adding purified wastewater that has not passed through an environmental buffer into a water distribution system. DPR may help address water shortages and is approved or is under consideration as a source of drinking water for several water-stressed population centers in the United States, however, there are no studies of health outcomes in populations who receive DPR drinking water. Our objective was to determine whether the introduction of DPR for certain public water systems in Texas was associated with changes in birth defect prevalence. We obtained data on maternal characteristics for all live births and birth defects cases regardless of pregnancy outcome in Texas from 2003 to 2017 from the Texas Birth Defects Registry and birth and fetal death records. The ridge augmented synthetic control method was used to model changes in birth defect prevalence (per 10,000 live births) following the adoption of DPR by four Texas counties in mid-2013, with county-level data on maternal age, percent women without a high school diploma, percent who identified as Hispanic/Latina or non-Hispanic/Latina Black, and rural-urban continuum code as covariates. There were nonstatistically significant increases in prevalence of all birth defects collectively (average treatment effect in the treated = 53.6) and congenital heart disease (average treatment effect in the treated = 287.3) since June 2013. The estimated prevalence of neural tube defects was unchanged. We estimated nonstatistically significant increases in birth defect prevalence following the implementation of DPR in four West Texas counties. Further research is warranted to inform water policy decisions.

Effects of Organic Equivalence Agreements on Organic Production: Evidence from the Synthetic Control Method

Effects of Organic Equivalence Agreements on Organic Production: Evidence from the Synthetic Control Method

Acaricide Potential of Creosote Bush (Larrea tridentata) Extracts in the Control of Varroa destructor in Apis mellifera

The aim of the present study was to assess the potential of natural compounds for the control of Varroa destructor in colonies of Apis mellifera, the antimite potential of the hydrolate and ethanolic extract (Leatricina®) of creosote bush (Larrea tridentata) was evaluated at a concentration 50%; contrasting them with the synthetic chemical amitraz and control under in vitro conditions (48 h) and in the hive (52 days). There were differences (p<0.05) in In vitro Varroa mortality with amitraz with higher values (97.9%) compared with hydrolate (53.1%) and Leatricina® (51.5%); Creosote bush extracts were similar (p> 0.05). In the field experiment, the reduction in the percentage of varroa infestation in adult bees was higher 84.9 % (p<0.05) for amitraz, while the hydrolate and Leatricina® showed differences (p<0.05) 49.5 and 72% respectively, the control group showed the lowest values. Even when the effectiveness of synthetic chemicals presents an evident superiority, the average efficacy and other benefits of natural compounds such as creosote bush extracts represent a viable and safe alternative for the control of V. destructor.

Doubly robust proximal synthetic controls.

To infer the treatment effect for a single treated unit using panel data, synthetic control (SC) methods construct a linear combination of control units' outcomes that mimics the treated unit's pre-treatment outcome trajectory. This linear combination is subsequently used to impute the counterfactual outcomes of the treated unit had it not been treated in the post-treatment period, and used to estimate the treatment effect. Existing SC methods rely on correctly modeling certain aspects of the counterfactual outcome generating mechanism and may require near-perfect matching of the pre-treatment trajectory. Inspired by proximal causal inference, we obtain two novel nonparametric identifying formulas for the average treatment effect for the treated unit: one is based on weighting, and the other combines models for the counterfactual outcome and the weighting function. We introduce the concept of covariate shift to SCs to obtain these identification results conditional on the treatment assignment. We also develop two treatment effect estimators based on these two formulas and generalized method of moments. One new estimator is doubly robust: it is consistent and asymptotically normal if at least one of the outcome and weighting models is correctly specified. We demonstrate the performance of the methods via simulations and apply them to evaluate the effectiveness of a pneumococcal conjugate vaccine on the risk of all-cause pneumonia in Brazil.

Policy legacies and energy transitions: Greening policies under sectoral reforms in Argentina and Chile

Under what conditions do greening policies lead to a fast deployment of solar and wind energies? Environmental economics assume that market factors and technological innovations are the main drivers of energy transitions. While these assumptions sometimes hold for well-functioning markets; in emerging economies, the combination of scarce capital, weak institutions, and market distortions creates specific challenges that make their paths to clean energies different from those of developed states. I analyze greening reforms of the electricity sector in Argentina and Chile, exploring instances of success and failure. Using archive data and interviews to stakeholders, I explain how previous sector structures created different market distortions that hindered an effective electricity transition even in the context of significant cost-savings from investment in new technologies. Successful greening policies entailed broader electricity-sector reforms that removed previous binding constraints and restructured incentives for key private-sector stakeholders. I corroborate this argument by employing synthetic control methods to evaluate policies’ impact. I show that broad greening policies led to a significant penetration of renewable energies: by 2020 the share of solar and wind energies in Argentina and Chile were about 7.3% and 13.6% higher than in the counterfactual scenarios in which the greening reforms had not occurred.

The impact of devolution on local health systems: Evidence from Greater Manchester, England

Devolution and decentralisation policies involving health and other government sectors have been promoted with a view to improve efficiency and equity in local service provision. Evaluations of these reforms have focused on specific health or care measures, but little is known about their full impact on local health systems. We evaluated the impact of devolution in Greater Manchester (England) on multiple outcomes using a whole system approach.We estimated the impact of devolution until February 2020 on 98 measures of health system performance, using the generalised synthetic control method and adjusting for multiple hypothesis testing. We selected measures from existing monitoring frameworks to populate the WHO Health System Performance Assessment framework. The included measures captured information on health system functions, intermediatory objectives, final goals, and social determinants of health. We identified which indicators were targeted in response to devolution from an analysis of 170 health policy intervention documents.Life expectancy (0.233 years, S.E. 0.012) and healthy life expectancy (0.603 years, S.E. 0.391) increased more in GM than in the estimated synthetic control group following devolution. These increases were driven by improvements in public health, primary care, hospital, and adult social care services as well as factors associated with social determinants of health, including a reduction in alcohol-related admissions (−110.1 admission per 100,000, S.E. 9.07). In contrast, the impact on outpatient, mental health, maternity, and dental services was mixed.Devolution was associated with improved population health, driven by improvements in health services and wider social determinants of health. These changes occurred despite limited devolved powers over health service resources suggesting that other mechanisms played an important role, including the allocation of sustainability and transformation funding and the alignment of decision-making across health, social care, and wider public services in the region.

Staggered deployment of gunshot detection technology in Chicago, IL: a matched quasi-experiment of gun violence outcomes

Abstract Objectives We examine the potential effects of gunshot detection technology longitudinally in Chicago through a synthetic control quasi-experiment. Methods Police districts receiving gunshot detection technology were compared to a synthetic control unit via a staggered difference-in-difference design. Across eleven unique gunshot detection technology deployment phases, the analyses produce results for aggregate, initial versus expanded, and phase-specific deployment effects across five gun violence outcome measures. Results Gunshot detection technology had no effect on fatal shootings, non-fatal shootings, general part I gun crimes, or shots fired calls for service. Gun recoveries significantly increased in the aggregate, initial, and expanded models, and in several individual phases relative to controls. Conclusions The results align with prior literature that has found a procedural benefit, but not a crime prevention benefit, of gunshot detection technology. Law enforcement agencies seeking crime prevention or reduction solutions may be better served by investing in other options.

The effects of membership expansion on credit union risk and returns

Between 1996 and 2022, regulatory changes led to over a thousand federally chartered credit unions converting to community charters, significantly increasing credit union membership. This study attempts to determine whether these developments improve safety and soundness by enabling credit unions to diversify their loan portfolios, or whether risk increases as the social capital of a tight common bond becomes diluted. We use two-way fixed effects, doubly robust and generalized synthetic control methods with state chartered credit unions and commercial banks as controls to estimate both intent-to-treat (ITT) and average treatment-effect-on-the-treated (ATT) impacts on credit union risk and returns. We find that conversions to community charter unambiguously improve credit union returns but the effects on risk are mixed: liquidity and capital fall, but there is no change in indicators of asset quality. Overall, during the 25-year period from 1998 to 2022, only 1.47% of community-chartered credit unions failed. The results suggest that social capital is no longer an important factor in reducing credit risk in countries with developed financial sectors like the U.S.

Engineered algal systems for the treatment of anaerobic digestate: A meta-analysis

The objective of this review was to provide quantitative insights into algal growth and nutrient removal in anaerobic digestate. To synthesize the relevant literature, a meta-analysis was conducted using data from 58 articles to elucidate key factors that impact algal biomass productivity and nutrient removal from anaerobic digestate. On average, algal biomass productivity in anaerobic digestate was significantly lower than that in synthetic control media (p < 0.05) but large variation in productivity was observed. A mixed-effects multiple regression model across study revealed that biological or chemical pretreatment of digestate significantly increase productivity (p < 0.001). In contrast, the commonly used practice of digestate dilution was not a significant factor in the model. High initial total ammonia nitrogen suppressed algal growth (p = 0.036) whereas initial total phosphorus concentration, digestate sterilization, CO2 supplementation, and temperature were not statistically significant factors. Higher growth corresponded with significantly higher NH4–N and phosphorus removal with a linear relationship of 6.4 mg NH4–N and 0.73 mg P removed per 100 mg of algal biomass growth (p < 0.001). The literature suggests that suboptimal algal growth in anaerobic digestate could be due to factors such as turbidity, high free ammonia, and residual organic compounds. This analysis shows that non-dilution approaches, such as biological or chemical pretreatment, for alleviating algal inhibition are recommended for algal digestate treatment systems.

Abstract 3618: High-avidity BCMA CAR and high-affinity, non-cleavable CD16 Fc receptor incorporated in off-the-shelf CAR T cells promote multi-antigen targeting and durable anti-tumor cytotoxicity in the treatment of multiple myeloma

Abstract Immune cell therapy has proven highly effective for the treatment of multiple myeloma (MM). However, key challenges remain that include disease relapse, limited patient access, and inability to effectively combine with existing standard-of-care therapies. Rapid progress in the development of off-the-shelf, multiplexed-engineered, induced pluripotent stem cell (iPSC)-derived cell therapies enables large-scale manufacture of immune cells incorporating multiple novel synthetic controls of cell function to improve cell fitness, enhance cell function, and enable synergistic combination with existing effective therapies such as CD38-targeted antibody (mAb) therapy. We have developed an iPSC-derived chimeric antigen receptor T (CAR-iT) cell therapy that uniquely leverages elements of both adaptive and innate immunity by incorporating a BCMA-targeted CAR (BCMA-CAR) derived from a scFv domain exhibiting high-binding affinity in the low nanomolar range, and a high-affinity, non-cleavable CD16 (hnCD16) Fc receptor to enable antibody-dependent cellular cytotoxicity with mAb therapy. The genetic deletion of CD38 gene was also incorporated to eliminate the possibility for CD38-mediated fratricide, and genetic deletion of TRAC gene was introduced to remove the potential risk of graft-versus-host disease in an allogeneic setting. These CAR iT cells, which were generated from a clonally-derived iPSC line, demonstrated homogenous expression of each genetic edit (&amp;gt;95% BCMA-CAR and hnCD16; &amp;lt;1% CD38 and TCR surface expression). Using a stringent, disseminated xenograft mouse model of multiple myeloma, MM.1S, which was allowed to achieve complete systemic engraftment during the initial 4 days, treatment with BCMA-CAR iT cells demonstrated comparable tumor cell clearance (p=0.0024 vs. vehicle at Day 17) to primary BCMA-CAR T cells (p=0.002 vs. vehicle). In combination with a CD38-targeted mAb to exploit hnCD16 and biallelic CD38 KO, BCMA-CAR iT cells are capable of dual-antigen targeting to address antigen escape and promote durable tumor control. To this end, a single dose of BCMA-CAR iT cells combined with daratumumab exhibited near complete TGI for the duration of the study (p&amp;lt;0.0001 vs. vehicle at Day 37). Together, these studies demonstrate CAR iT cells incorporating a high-avidity BCMA CAR and high-affinity, non-cleavable CD16 Fc receptor can uniquely leverage elements of both adaptive and innate immunity and can be combined with CD38-targeted mAb to potentially outcompete primary BCMA CAR T cells. As these CAR iT cells can be administered off-the-shelf, key challenges associated with current immune cell therapy, such as patient access and inability to synergize with standard-of-care therapies, can be addressed for the treatment of relapsed/refractory MM. Citation Format: John Reiser, Alison O'Connor, Bryan Hancock, Spas Markov, Brian Groff, Alma Gutierrez, Miguel Meza, Mark Jelcik, Yijia Pan, Alex Garcia, Bobby Goulding, Matthew Denholtz, Tom Lee, Ramzey Abujarour, Ryan Bjordahl, Armin Rehm, Raedun Clarke, Jode Goodridge, Bahram Valamehr. High-avidity BCMA CAR and high-affinity, non-cleavable CD16 Fc receptor incorporated in off-the-shelf CAR T cells promote multi-antigen targeting and durable anti-tumor cytotoxicity in the treatment of multiple myeloma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3618.

Synthetic control with target sticking for on-orbit capturing using a dual-arm space robot

On-orbit capturing is a crucial step in the application of dual-arm space robots, aiming to accurately grasp a moving target and avoid damage to the arms terminal parts (i.e. the end effectors) due to contact force saturation. This paper presents a synthetic control method with target sticking for on-orbit capturing using a dual-arm space robot system from the approaching phase to pre-grasping phase. In the approaching phase, an online trajectory planning method based on visual servoing is proposed to obtain the desired trajectories for end effectors in work space. Then the joint torques are designed by the inverse kinematics and inverse dynamics to track the desired trajectories. Different from most of the current research, a new sticking phase is proposed after the approaching phase and before the pre-grasping phase. In the sticking phase, a force and motion control method is designed to maintain a close relative distance between end effectors and the target, which can avoid saturation of contact forces and avoid damage to the end effectors. In what follows, an impedance control method is proposed in the pre-grasping phase to absorb the impact energy and grasp the target accurately. The synthetic control strategy integrates the controllers of all the phases mentioned above. Automatic switching among the phases is realized by using logic judgment according to the system real states, which is more consistent with the real capturing environment. Finally, numerical simulation results demonstrate the effectiveness of the proposed synthetic control scheme. The results can be applied to the trajectory planning and control of on-orbit capturing, avoiding contact force saturation and ensuring the safety of the system.

From the French franc to the euro, is there an economic impact for the CFA franc zone countries? A ‘bias-corrected’ synthetic control method

From the French franc to the euro, is there an economic impact for the CFA franc zone countries? A ‘bias-corrected’ synthetic control method