pwc-archive/papers-with-abstracts huggingface dataset:
The Hidden Subsidy of the Affordable Care Act
Authors: Liam Sigaud, Markus Bjoerkheim, Vitor Melo
Date: 2024-07-09 00:00:00

Under the ACA, the federal government paid a substantially larger share of medical costs of newly eligible Medicaid enrollees than previously eligible ones. States could save up to 100% of their per-enrollee costs by reclassifying original enrollees into the newly eligible group. We examine whether this fiscal incentive changed states' enrollment practices. We find that Medicaid expansion caused large declines in the number of beneficiaries enrolled in the original Medicaid population, suggesting widespread reclassifications. In 2019 alone, this phenomenon affected 4.4 million Medicaid enrollees at a federal cost of $8.3 billion. Our results imply that reclassifications inflated the federal cost of Medicaid expansion by 18.2%.
The heterogeneous impact of the EU-Canada agreement with causal machine learning
Authors: Lionel Fontagné, Francesca Micocci, Armando Rungi
Date: 2024-07-10 00:00:00
Tasks: Matrix Completion

This paper introduces a causal machine learning approach to investigate the impact of the EU-Canada Comprehensive Economic Trade Agreement (CETA). We propose a matrix completion algorithm on French customs data to obtain multidimensional counterfactuals at the firm, product and destination levels. We find a small but significant positive impact on average at the product-level intensive margin. On the other hand, the extensive margin shows product churning due to the treaty beyond regular entry-exit dynamics: one product in eight that was not previously exported substitutes almost as many that are no longer exported. When we delve into the heterogeneity, we find that the effects of the treaty are higher for products at a comparative advantage. Focusing on multiproduct firms, we find that they adjust their portfolio in Canada by reallocating towards their first and most exported product due to increasing local market competition after trade liberalization. Finally, multidimensional counterfactuals allow us to evaluate the general equilibrium effect of the CETA. Specifically, we observe trade diversion, as exports to other destinations are re-directed to Canada.
The role of green ammonia in meeting challenges towards a sustainable development in China
Authors: Hanxin Zhao
Date: 2024-07-10 00:00:00

This paper discusses the adoption of a green ammonia economy in meeting challenges in China's sustainable development. First, key challenges in China's energy transition, industry decarbonziation and regional sustainable development are explored. The coal-dominated energy consumption has placed great obstacles in achieving energy transition and led to massive CO2 emission since the large-scale industrialization. The high dependency on oil and gas import has threatened the energy security. A DEA model is applied for obtaining green total factor productivities of China's six administrative regions, with which, imbalanced and unsustainable regional development is identified. Second, the role of green ammonia in meeting the sustainability challenges is analysed. Ammonia is examined to be a flexible and economic option for large-scale hydrogen transport and storage. Co-firing ammonia in coal power generation at 3% rate is evaluated as an option for achieving low-carbon transition by 2030. The adoption of a green ammonia economy in China is discussed from energy, environmental and economic aspects. The practice can decline fossil energy consumption, enhance energy security, and facilitate renewable energy delivery and storage, industry decarbonization, and regional development. We assume the findings and results contribute to addressing sustainability challenges and realizing a hydrogen economy in China.
Mapping Local Green Hydrogen Cost-Potentials by a Multidisciplinary Approach
Authors: Shitab Ishmam, Heidi Heinrichs, Christoph Winkler, Bagher Bayat, Amin Lahnaoui, Solomon Agbo, Edgar Ubaldo Pena Sanchez, David Franzmann, Nathan Ojieabu, Celine Koerner, Youpele Micheal, Bamidele Oloruntoba, Carsten Montzka, Harry Vereecken, Harrie-Jan Hendricks-Franssen, Jeerawan Brendt, Simon Brauner, Wilhelm Kuckshinrichs, Sandra Venghaus, Daouda Kone, Bruno Korgo, Kehinde Ogunjobi, Vasco Chiteculo, Jane Olwoch, Zachary Getenga, Jochen Linßen, Detlef Stolten
Date: 2024-07-10 00:00:00

For fast-tracking climate change response, green hydrogen is key for achieving greenhouse gas neutral energy systems. Especially Sub-Saharan Africa can benefit from it enabling an increased access to clean energy through utilizing its beneficial conditions for renewable energies. However, developing green hydrogen strategies for Sub-Saharan Africa requires highly detailed and consistent information ranging from technical, environmental, economic, and social dimensions, which is currently lacking in literature. Therefore, this paper provides a comprehensive novel approach embedding the required range of disciplines to analyze green hydrogen cost-potentials in Sub-Saharan Africa. This approach stretches from a dedicated land eligibility based on local preferences, a location specific renewable energy simulation, locally derived sustainable groundwater limitations under climate change, an optimization of local hydrogen energy systems, and a socio-economic indicator-based impact analysis. The capability of the approach is shown for case study regions in Sub-Saharan Africa highlighting the need for a unified, interdisciplinary approach.
The Pass-through of Retail Crime
Authors: Carl Hase, Johannes Kasinger
Date: 2024-07-09 00:00:00

This paper shows that retailers increase prices in response to organized retail crime. We match store-level crime data to scanner data from the universe of transactions for cannabis retailers in Washington state. Using quasi-experimental variation from robberies and burglaries, we find a 1.5-1.8% price increase at victimized stores and nearby competitors. This rise is not driven by short-to-medium-term demand changes but is consistent with an own-cost shock. Effects are larger for independent stores and less concentrated markets. We estimate that crime imposes a 1% "hidden" unit tax on affected stores, implying $33.9 million additional social costs, primarily borne by consumers.
Carbon Pricing and Resale in Emission Trading Systems
Authors: Peyman Khezr
Date: 2024-07-10 00:00:00

Secondary markets and resale are integral components of all emission trading systems. Despite the justification for these secondary trades, such as unpredictable demand, they may encourage speculation and result in the misallocation of permits. In this paper, our aim is to underscore the importance of efficiency in the initial allocation mechanism and to explore how concerns leading to the establishment of secondary markets, such as uncertain demand, can be addressed through alternative means, such as frequent auctions. We demonstrate that the existence of a secondary market could lead to higher untruthful bids in the auction, further encouraging speculation and the accumulation of rent. Our results suggest that an inefficient initial allocation could enable speculators with no use value for the permits to bid in the auction and subsequently earn rents in secondary markets by trading these permits. Even if the secondary market operates efficiently, the resulting rent, which represents a potential loss of auction revenue, cannot be overlooked.
Optimal Decision Mechanisms for Committees: Acquitting the Guilty
Authors: Deniz Kattwinkel, Alexander Winter
Date: 2024-07-10 00:00:00

A group of privately informed agents chooses between two alternatives. How should the decision rule be designed if agents are known to be biased in favor of one of the options? We address this question by considering the Condorcet Jury Setting as a mechanism design problem. Applications include the optimal decision mechanisms for boards of directors, political committees, and trial juries. While we allow for any kind of mechanism, the optimal mechanism is a voting mechanism. In the terminology of the trial jury example: When jurors (agents) are more eager to convict than the lawmaker (principal), then the defendant should be convicted if and only if neither too many nor too few jurors vote to convict. This kind of mechanism accords with a judicial procedure from ancient Jewish law.
Jump Plus AM-FM Mode Decomposition
Authors: Mojtaba Nazari, Anders Rosendal Korshøj, Naveed Ur Rehman
Date: 2024-07-10 00:00:00
Tasks: EEG

A novel method for decomposing a nonstationary signal into amplitude- and frequency-modulated (AM-FM) oscillations and discontinuous (jump) components is proposed. Current nonstationary signal decomposition methods are designed to either obtain constituent AM-FM oscillatory modes or the discontinuous and residual components from the data, separately. Yet, many real-world signals of interest simultaneously exhibit both behaviors i.e., jumps and oscillations. Currently, no available method can extract jumps and AM-FM oscillatory components directly from the data. In our novel approach, we design and solve a variational optimization problem to accomplish this task. The optimization formulation includes a regularization term to minimize the bandwidth of all signal modes for effective oscillation modeling, and a prior for extracting the jump component. Our method addresses the limitations of conventional AM-FM signal decomposition methods in extracting jumps, as well as the limitations of existing jump extraction methods in decomposing multiscale oscillations. By employing an optimization framework that accounts for both multiscale oscillatory components and discontinuities, our methods show superior performance compared to existing decomposition techniques. We demonstrate the effectiveness of our approaches on synthetic, real-world, single-channel, and multivariate data, highlighting their utility in three specific applications: Earth's electric field signals, electrocardiograms (ECG), and electroencephalograms (EEG).
Pilot-Based SFO Estimation for Bistatic Integrated Sensing and Communication
Authors: Lucas Giroto de Oliveira, Yueheng Li, Silvio Mandelli, David Brunner, Marcus Henninger, Xiang Wan, Tie Jun Cui, Thomas Zwick, Benjamin Nuss
Date: 2024-07-10 00:00:00
Tasks: Integrated sensing and communication, ISAC

Enabling bistatic radar sensing within the context of integrated sensing and communication (ISAC) for future sixth generation mobile networks demands strict synchronization accuracy, which is particularly challenging to be achieved with over-the-air synchronization. Existing algorithms handle time and frequency offsets adequately, but provide insufficiently accurate sampling frequency offset (SFO) estimates that result in degradation of obtained radar images in the form of signal-to-noise ratio loss and migration of range and Doppler shift. This article introduces an SFO estimation algorithm named tilt inference of time offset (TITO) for orthogonal frequency-division multiplexing (OFDM)-based ISAC. Using available pilot subcarriers, TITO obtains channel impulse response estimates and extracts information on the SFO-induced delay migration to a dominant reference path with constant range, Doppler shift, and angle between transmit and receive ISAC nodes. TITO then adaptively selects the delay estimates that are only negligibly impaired by SFO-induced intersymbol interference, ultimately employing them to estimate the SFO. Assuming a scenario without a direct line-of-sight (LoS) between the aforementioned transmitting and receiving ISAC nodes, a system concept with a relay reflective intelligent surface (RIS) is used to create the aforementioned reference path is proposed. Besides a mathematical derivation of accuracy bounds, simulation and measurements at 26.2 GHz are presented to demonstrate TITO's superiority over existing methods in terms of SFO estimation accuracy and robustness.
Closed-Form EGN Model with Comprehensive Raman Support
Authors: Yanchao Jiang, Antonino Nespola, Stefano Straullu, Alberto Tanzi, Stefano Piciaccia, Fabrizio Forghieri, Dario Pilori, Pierluigi Poggiolini
Date: 2024-07-10 00:00:00
Tasks: Form, model

We present a series of experiments testing the accuracy of a new closed-form multiband EGN model, carried out over a full-Raman 9-span C+L link. Transmission regimes ranged from linear to strongly non-linear with large ISRS. We found good correspondence between predicted and measured performance.
Spatial Frequencies and Degrees of Freedom: Their Roles in Near-Field Communications
Authors: Alva Kosasih, Özlem Tuğfe Demir, Nikolaos Kolomvakis, Emil Björnson
Date: 2024-07-10 00:00:00

As wireless technology begins to utilize physically larger arrays and/or higher frequencies, the transmitter and receiver will reside in each other's radiative near field. This fact gives rise to unusual propagation phenomena such as spherical wavefronts and beamfocusing, creating the impression that new spatial dimensions -- called degrees-of-freedom (DoF) -- can be exploited in the near field. However, this is a fallacy because the theoretically maximum DoF are already achievable in the far field. This paper sheds light on these issues by providing a tutorial on spatial frequencies, which are the fundamental components of wireless channels, and by explaining their role in characterizing the DoF in the near and far fields. In particular, we demonstrate how a single propagation path utilizes one spatial frequency in the far field and an interval of spatial frequencies in the near field. We explain how the array geometry determines the number of distinguishable spatial frequency bins and, thereby, the spatial DoF. We also describe how to model near-field multipath channels and their spatial correlation matrices. Finally, we discuss the research challenges and future directions in this field.
Timing Recovery for Non-Orthogonal Multiple Access with Asynchronous Clocks
Authors: Qingxin Lu, Haide Wang, Wenxuan Mo, Ji Zhou, Weiping Liu, Changyuan Yu
Date: 2024-07-10 00:00:00

A passive optical network (PON) based on non-orthogonal multiple access (NOMA) meets low latency and high capacity. In the NOMA-PON, the asynchronous clocks between the strong and weak optical network units (ONUs) cause the timing error and phase noise on the signal of the weak ONU. The theoretical derivation shows that the timing error and phase noise can be independently compensated. In this Letter, we propose a timing recovery (TR) algorithm based on an absolute timing error detector (Abs TED) and a pilot-based carrier phase recovery (CPR) to eliminate the timing error and phase noise separately. An experiment for 25G NOMA-PON is set up to verify the feasibility of the proposed algorithms. The weak ONU can achieve the 20% soft-decision forward error correction limit after compensating for timing error and phase noise. In conclusion, the proposed TR and the pilot-based CPR show great potential for the NOMA-PON.
Accurate Radar-Based Heartbeat Measurement Using Higher Harmonic Components
Authors: Itsuki Iwata, Kimitaka Sumi, Yuji Tanaka, Takuya Sakamoto
Date: 2024-07-10 00:00:00

This study proposes a radar-based heartbeat measurement method that uses the absolute value of the second derivative of the complex radar signal, rather than its phase, and the variational mode extraction method, which is a type of mode decomposition algorithm. We show that the proposed second-derivative-based approach can amplify the heartbeat component in radar signals effectively and also confirm that use of the variational mode extraction method represents an efficient way to emphasize the heartbeat component amplified via the second-derivative-based approach. We demonstrate estimation of the heart interbeat intervals using the proposed approach in combination with the topology method, which is an accurate interbeat interval estimation method. The performance of the proposed method is evaluated quantitatively using data obtained from eleven participants that were measured using a millimeter-wave radar system. When compared with conventional methods based on the phase of the complex radar signal, our proposed method can achieve higher accuracy when estimating the heart interbeat intervals; the correlation coefficient for the proposed method was increased by 0.20 and the root-mean-square error decreased by 23%.
Pseudo-perplexity in One Fell Swoop for Protein Fitness Estimation
Authors: Pranav Kantroo, Günter P. Wagner, Benjamin B. Machta
Date: 2024-07-09 00:00:00
Tasks: Computational Efficiency, Language Modeling, Language Modelling, Masked Language Modeling

Protein language models trained on the masked language modeling objective learn to predict the identity of hidden amino acid residues within a sequence using the remaining observable sequence as context. They do so by embedding the residues into a high dimensional space that encapsulates the relevant contextual cues. These embedding vectors serve as an informative context-sensitive representation that not only aids with the defined training objective, but can also be used for other tasks by downstream models. We propose a scheme to use the embeddings of an unmasked sequence to estimate the corresponding masked probability vectors for all the positions in a single forward pass through the language model. This One Fell Swoop (OFS) approach allows us to efficiently estimate the pseudo-perplexity of the sequence, a measure of the model's uncertainty in its predictions, that can also serve as a fitness estimate. We find that ESM2 OFS pseudo-perplexity performs nearly as well as the true pseudo-perplexity at fitness estimation, and more notably it defines a new state of the art on the ProteinGym Indels benchmark. The strong performance of the fitness measure prompted us to investigate if it could be used to detect the elevated stability reported in reconstructed ancestral sequences. We find that this measure ranks ancestral reconstructions as more fit than extant sequences. Finally, we show that the computational efficiency of the technique allows for the use of Monte Carlo methods that can rapidly explore functional sequence space.
Differential Effects of Sequence-Local versus Nonlocal Charge Patterns on Phase Separation and Conformational Dimensions of Polyampholytes as Model Intrinsically Disordered Proteins
Authors: Tanmoy Pal, Jonas Wessén, Suman Das, Hue Sun Chan
Date: 2024-07-09 00:00:00

Conformational properties of intrinsically disordered proteins (IDPs) are governed by a sequence-ensemble relationship. To differentiate the impact of sequence-local versus sequence-nonlocal features of an IDP's charge pattern on its conformational dimensions and its phase-separation propensity, the charge "blockiness'' $\kappa$ and the nonlocality-weighted sequence charge decoration (SCD) parameters are compared for their correlations with isolated-chain radii of gyration ($R_{\rm g}$s) and upper critical solution temperatures (UCSTs) of polyampholytes modeled by random phase approximation, field-theoretic simulation, and coarse-grained molecular dynamics. SCD is superior to $\kappa$ in predicting $R_{\rm g}$ because SCD accounts for effects of contact order, i.e., nonlocality, on dimensions of isolated chains. In contrast, $\kappa$ and SCD are comparably good, though nonideal, predictors of UCST because frequencies of interchain contacts in the multiple-chain condensed phase are less sensitive to sequence positions than frequencies of intrachain contacts of an isolated chain, as reflected by $\kappa$ correlating better with condensed-phase interaction energy than SCD.
The mouth speaks as much as the eyes: Free-ranging dogs depend on inner facial features for human recognition
Authors: Rohan Sarkar, Tuhin Subhra Pal, Sandip Murmu, Anindita Bhadra
Date: 2024-07-09 00:00:00

The human face is a multi-signal system continuously transmitting information of identity and emotion. In shared human-animal environments, the face becomes a reliable tool of heterospecific recognition. Because humans display mixed behaviour and pose differential risk to animals, adaptable decision-making based on recognition and classification of humans confer a fitness benefit. The human-dog dyad is an ideal model to study heterospecific recognition due to their shared history, niche overlap, and cognitive co-evolution. Multiple studies on pet dogs have examined their human facial information processing. However, no study has examined these perceptual abilities in free-living populations in their natural habitat where the human-dog relationship is more complex and impacts survival. Comprehensive behavioural analysis of 416 free-ranging dogs in an approach-based task with differential facial occlusion of a human, demonstrated that these dogs recognize and discriminate between familiar and unfamiliar people. Negative behaviours like aggression and avoidance were unlikely to be displayed. Inner facial components like eyes, nose and mouth were more important than outer components like hair in human recognition. Unlike in pet dogs, the occlusion of even a single inner component of the face prevented recognition by facial cue alone. Personality and habitat conditions influenced the behavioural strategy adopted by the dogs too. Considering the ambiguous nature of human interactions, recognition and response in free-ranging dogs relied on dual assessment of identity and intent of a human based, in part, on their ontogeny. Such a cue-processing system highlights the selection pressures inherent in the unpredictable environment of free-living populations.
Molecular Quantum (MolQ) Communication Channel in the Gut-Brain Axis Synapse
Authors: Bitop Maitra, Ozgur B. Akan
Date: 2024-06-24 00:00:00

The gut-brain axis is the communication link between the gut and the brain. Although it is known that the gut-brain axis plays a pivotal role in homeostasis, its overall mechanism is still not known. However, for neural synapses, classical molecular communication is described by the formation of ligand-receptor complexes, which leads to the opening of ion channels. Moreover, there are some conditions that need to be fulfilled before the opening of the ion channel. In this study, we consider the gut-brain axis, where neurotransmitters diffuse through the synaptic cleft, considering molecular communication. On the vagus nerve (VN) membrane, i.e., the post-synaptic membrane of the synapse, it undergoes a quantum communication (QC), which initiates the opening of the ion channel, thus initiating the communication signal from the gut to the brain. It evolves a new paradigm of communication approach, Molecular Quantum (MolQ) communication. Based on the QC model, we theoretically analyze the output states, and QC is simulated considering the incoming neurotransmitter's concentration and validated by analyzing the entropy and the mutual information of the input, i.e., neurotransmitter's concentration, and output, i.e., ion channel opening.
Alternatives to the statistical mass confusion of testing for no-effect
Authors: Josh L. Morgan
Date: 2024-06-28 00:00:00

In cell biology, statistical analysis means testing the hypothesis that there was no effect. This weak form of hypothesis testing neglects effect size, is universally misinterpreted, and is disastrously prone to error when combined with high-throughput cell biology. The solution is for analysis of measurements to start and end with an interpretation of effect size.