
Ahrer, E. M., Alderson, L., Batalha, N. M., Batalha, N. E., Bean, J. L., Beatty, T. G., et al. (2023). Identification of carbon dioxide in an exoplanet atmosphere. Nature, Early Access.
Abstract: Carbon dioxide (CO2) is a key chemical species that is found in a wide range of planetary atmospheres. In the context of exoplanets, CO2 is an indicator of the metal enrichment (that is, elements heavier than helium, also called 'metallicity')(13), and thus the formation processes of the primary atmospheres of hot gas giants(46). It is also one of the most promising species to detect in the secondary atmospheres of terrestrial exoplanets(79). Previous photometric measurements of transiting planets with the Spitzer Space Telescope have given hints of the presence of CO2, but have not yielded definitive detections owing to the lack of unambiguous spectroscopic identification(1012). Here we present the detection of CO2 in the atmosphere of the gas giant exoplanet WASP39b from transmission spectroscopy observations obtained with JWST as part of the Early Release Science programme(13,14). The data used in this study span 3.05.5micrometres in wavelength and show a prominent CO2 absorption feature at 4.3micrometres (26sigma significance). The overall spectrum is well matched by onedimensional, tentimes solar metallicity models that assume radiativeconvectivethermochemical equilibrium and have moderate cloud opacity. These models predict that the atmosphere should have water, carbon monoxide and hydrogen sulfide in addition to CO2, but little methane. Furthermore, we also tentatively detect a small absorption feature near 4.0micrometres that is not reproduced by these models.



Aledo, J. A., Goles, E., MontalvaMedel, M., Montealegre, P., & Valverde, J. C. (2023). Symmetrizable Boolean networks. Inf. Sci., 626, 787–804.
Abstract: In this work, we provide a procedure that allows us to transform certain kinds of deterministic Boolean networks on minterm or maxterm functions into symmetric ones, so inferring that such symmetrizable networks can present only periodic points of periods 1 or 2. In particular, we deal with generalized parallel (or synchronous) dynamical systems (GPDS) over undirected graphs, i. e., discrete parallel dynamical systems over undirected graphs where some of the selfloops may not appear. We also study the class of antisymmetric GPDS (which are nonsymmetrizable), proving that their periodic orbits have period 4. In addition, we introduce a class of nonsymmetrizable systems which admit periodic orbits with arbitrary large periods.



AlvarezMiranda, E., Pereira, J., Vargas, C., & Vila, M. (2022). Variabledepth local search heuristic for assembly line balancing problems. Int. J. Prod. Res., 61(9), 3103–3121.
Abstract: Assembly lines are production flow systems wherein activities are organised around a line consisting of various workstations through which the product flows. At each station, the product is assembled through a subset of operations. The assembly line balancing problem (ALBP) consists of allocating operations between stations to maximise the system efficiency. In this study, a variabledepth local search algorithm is proposed for solving simple assembly line balancing problems (SALBPs), which are the most widely studied versions of the ALBP. Although the stateoftheart techniques for solving the SALBP consist of exact enumerationbased methods or heuristics, this paper proposes a local searchbased heuristic using variablelength sequences that allow the solution space to be efficiently explored. The proposed algorithm improves the best solution known for multiple instances reported in the literature, indicating that its efficiency is comparable to those of the stateoftheart method for solving the SALBP. Moreover, the characteristics of the instances for which the proposed procedure provides a better solution than previously reported construction procedures are investigated.



Arulraj, A., Murugesan, P. K., Rajkumar, C., Zamorano, A. T., & Mangalaraja, R. V. (2023). Nanoarchitectonics of Layered Metal ChalcogenidesBased Ternary Electrocatalyst for Water Splitting. Energies, 16(4), 1669.
Abstract: The research on renewable energy is actively looking into electrocatalysts based on transition metal chalcogenides because nanostructured electrocatalysts support the higher intrinsic activity for both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). A major technique for facilitating the conversion of renewable and sustainable energy is electrochemical water splitting. The aim of the review is to discuss the revelations made when trying to alter the internal and external nanoarchitectures of chalcogenidesbased electrocatalysts to enhance their performance. To begin, a general explanation of the watersplitting reaction is given to clarify the key factors in determining the catalytic performance of nanostructured chalcogenidesbased electrocatalysts. To delve into the many ways being employed to improve the HER's electrocatalytic performance, the general fabrication processes utilized to generate the chalcogenidesbased materials are described. Similarly, to enhance the OER performance of chalcogenidesbased electrocatalysts, the applied complementary techniques and the strategies involved in designing the bifunctional watersplitting electrocatalysts (HER and OER) are explained. As a conclusive remark, the challenges and future perspectives of chalcogenidebased electrocatalysts in the context of water splitting are summarized.



Aylwin, R., Henriquez, F., & Schwab, C. (2023). ReLU Neural Network Galerkin BEM. J. Sci. Comput., 95(2), 41.
Abstract: We introduce Neural Network (NN for short) approximation architectures for the numerical solution of Boundary Integral Equations (BIEs for short). We exemplify the proposed NN approach for the boundary reduction of the potential problem in two spatial dimensions. We adopt a Galerkin formulationbased method, in polygonal domains with a finite number of straight sides. Trial spaces used in the Galerkin discretization of the BIEs are built by using NNs that, in turn, employ the socalled Rectified Linear Units (ReLU) as the underlying activation function. The ReLUNNs used to approximate the solutions to the BIEs depend nonlinearly on the parameters characterizing the NNs themselves. Consequently, the computation of a numerical solution to a BIE by means of ReLUNNs boils down to a fine tuning of these parameters, in network training. We argue that ReLUNNs of fixed depth and with a variable width allow us to recover wellknown approximation rate results for the standard Galerkin Boundary Element Method (BEM). This observation hinges on existing wellknown properties concerning the regularity of the solution of the BIEs on Lipschitz, polygonal boundaries, i.e. accounting for the effect of corner singularities, and the expressive power of ReLUNNs over different classes of functions. We prove that shallow ReLUNNs, i.e. networks having a fixed, moderate depth but with increasing width, can achieve optimal order algebraic convergence rates. We propose novel loss functions for NN training which are obtained using computable, local residual a posteriori error estimators with ReLUNNs for the numerical approximation of BIEs. We find that weighted residual estimators, which are reliable without further assumptions on the quasiuniformity of the underlying mesh, can be employed for the construction of computationally efficient loss functions for ReLUNN training. The proposed framework allows us to leverage on stateoftheart computational deep learning technologies such as TENSORFLOW and TPUs for the numerical solution of BIEs using ReLUNNs. Exploratory numerical experiments validate our theoretical findings and indicate the viability of the proposed ReLUNN Galerkin BEM approach.



Aylwin, R., JerezHanckes, C., Schwab, C., & Zech, J. (2023). Multilevel Domain Uncertainty Quantification in Computational Electromagnetics. Math. Models Methods Appl. Sci., 33(04), 877–921.
Abstract: We continue our study [Domain Uncertainty Quantification in Computational Electromagnetics, JUQ (2020), 8:301341] of the numerical approximation of timeharmonic electromagnetic fields for the Maxwell lossy cavity problem for uncertain geometries. We adopt the same affineparametric shape parametrization framework, mapping the physical domains to a nominal polygonal domain with piecewise smooth maps. The regularity of the pullback solutions on the nominal domain is characterized in piecewise Sobolev spaces. We prove error convergence rates and optimize the algorithmic steering of parameters for edgeelement discretizations in the nominal domain combined with: (a) multilevel Monte Carlo sampling, and (b) multilevel, sparsegrid quadrature for computing the expectation of the solutions with respect to uncertain domain ensembles. In addition, we analyze sparsegrid interpolation to compute surrogates of the domaintosolution mappings. All calculations are performed on the polyhedral nominal domain, which enables the use of standard simplicial finite element meshes. We provide a rigorous fully discrete error analysis and show, in all cases, that dimensionindependent algebraic convergence is achieved. For the multilevel sparsegrid quadrature methods, we prove higher order convergence rates which are free from the socalled curse of dimensionality, i.e. independent of the number of parameters used to parametrize the admissible shapes. Numerical experiments confirm our theoretical results and verify the superiority of the sparsegrid methods.



Becker, F., Montealegre, P., Rapaport, I., & Todinca, I. (2020). The Impact Of Locality In The Broadcast Congested Clique Model. SIAM Discret. Math., 34(1), 682–700.
Abstract: The broadcast congested clique model (BCLIQUE) is a messagepassing model of distributed computation where n nodes communicate with each other in synchronous rounds. First, in this paper we prove that there is a oneround, deterministic algorithm that reconstructs the input graph G if the graph is ddegenerate, and rejects otherwise, using bandwidth b = O(d . log n). Then, we introduce a new parameter to the model. We study the situation where the nodes, initially, instead of knowing their immediate neighbors, know their neighborhood up to a fixed radius r. In this new framework, denoted BCLIQuE[r], we study the problem of detecting, in G, an induced cycle of length at most k (CYCLE <= k) and the problem of detecting an induced cycle of length at least k +1 (CYCLE>k). We give upper and lower bounds. We show that if each node is allowed to see up to distance r = left perpendicular k/2 right perpendicular + 1, then a polylogarithmic bandwidth is sufficient for solving CYCLE>k with only two rounds. Nevertheless, if nodes were allowed to see up to distance r = left perpendicular k/3 right perpendicular, then any oneround algorithm that solves CYCLE>k needs the bandwidth b to be at least Omega(n/ log n). We also show the existence of a oneround, deterministic BCLIQUE algorithm that solves CYCLE <= k with bandwitdh b = O(n(1/left perpendicular k/2 right perpendicular). log n). On the negative side, we prove that, if epsilon <= 1/3 and 0 < r <= k/4, then any epsilonerror, Rround, bbandwidth algorithm in the BCLIQUE[r] model that solves problem CYCLE(<= k )satisfies R . b = Omega(n(1/left perpendicular k/2 right perpendicular)).



Benedikt, M., Kikot, S., OstropolskiNalewaja, P., & Romero, M. (2023). On Monotonic Determinacy and Rewritability for Recursive Queries and Views. ACM Trans. Comput. Log., 24(2), 16.
Abstract: A query Q is monotonically determined over a set of views V if Q can be expressed as a monotonic function of the view image. In the case of relational algebra views and queries, monotonic determinacy coincides with rewritability as a union of conjunctive queries, and it is decidable in important special cases, such as for conjunctive query views and queries. We investigate the situation for views and queries in the recursive query language Datalog. We give both positive and negative results about the ability to decide monotonic determinacy, and also about the coincidence of monotonic determinacy with Datalog rewritability.



Bravo, V., Hernandez, R., & Venegas, O. (2023). TwoPoint Distortion Theorems for Harmonic Mappings. Bull. Malaysian Math. Sci., 46(3), 100.
Abstract: We establish twopoint distortion theorems for sensepreserving planar harmonic map pings f = h + g in the unit disk D which satisfy harmonic versions of the univalence criteria due to Becker and Nehari. In addition, we also find twopoint distortion theorems for the cases when h is a normalized convex function and, more generally, when h(D) is a clinearly connected domain.



Bugedo, G., Tobar, E., Alegria, L., Oviedo, V., Arellano, D., Basoalto, R., et al. (2023). Development of mechanical ventilators in Chile. Chronicle of the initiative "Un Respiro para Chile. Rev. Med. Chile, 150(7), 958–965.
Abstract: At the beginning of the COVID19 pandemic in Chile, in March 2020, a projection indicated that a significant group of patients with pneumonia would require admission to an Intensive Care Unit and connection to a mechanical ventilator. Therefore, a paucity of these devices and other supplies was predicted. The initiative “Un respiro para Chile” brought together many people and institutions, public and private. In the course of three months, it allowed the design and building of several ventilatory assistance devices, which could be used in critically ill patients.



Calderon, F., Lozada, A., Morales, P., BorquezParedes, D., Jara, N., Olivares, R., et al. (2022). Heuristic Approaches for Dynamic Provisioning in MultiBand Elastic Optical Networks. IEEE Commun. Lett., 26(2), 379–383.
Abstract: Multiband elastic optical networks are a promising alternative to meet the bandwidth demand of the evergrowing Internet traffic. In this letter, we propose a family of band allocation algorithms for multiband elastic optical networks. Employing simulation, we evaluate the blocking performance of 3 algorithms of such a family and compare their performance with the only heuristic proposed to date. Results show that the three new algorithms outperform the previous proposal, with up to one order of magnitude improvement. We expect these results to help advance the area of dynamic resource allocation in multiband elastic optical networks.



Canessa, E., Chaigneau, S. E., Moreno, S., & Lagos, R. (2023). CPNCoverageAnalysis: An R package for parameter estimation in conceptual properties norming studies. Behav. Res. Methods, 55, 554–569.
Abstract: In conceptual properties norming studies (CPNs), participants list properties that describe a set of concepts. From CPNs, many different parameters are calculated, such as semantic richness. A generally overlooked issue is that those values are
only point estimates of the true unknown population parameters. In the present work, we present an R package that allows us to treat those values as population parameter estimates. Relatedly, a general practice in CPNs is using an equal number of participants who list properties for each concept (i.e., standardizing sample size). As we illustrate through examples, this procedure has negative effects on data�s statistical analyses. Here, we argue that a better method is to standardize coverage (i.e., the proportion of sampled properties to the total number of properties that describe a concept), such that a similar coverage is achieved across concepts. When standardizing coverage rather than sample size, it is more likely that the set of concepts in a CPN all exhibit a similar representativeness. Moreover, by computing coverage the researcher can decide whether the
CPN reached a sufficiently high coverage, so that its results might be generalizable to other studies. The R package we make available in the current work allows one to compute coverage and to estimate the necessary number of participants to reach a target coverage. We show this sampling procedure by using the R package on real and simulated CPN data.



CanoMartinez, M. J., Carrasco, M., Sandoval, J., & GonzalezMartin, C. (2022). Quantitative Analysis of Visual Representation of Sign Elements in COVID19 Context. Empir. Stud. Arts, 41(1), 31–51.
Abstract: Visual representation as a means of communication uses elements to build a narrative. We propose using computer analysis to perform a quantitative analysis of the elements used in the visual creations that have been produced in reference to the epidemic, using 927 images compiled from The Covid Art Museum's Instagram account. This process has been carried out with techniques based on deep learning to detect objects contained in each study image. The research reveals the elements that are repeated in images to create narratives and the relations of association that are established in the sample. The predominant discourses in the sample do not show concern for the effects of illness. On the contrary, the impact and effects of confinement, through the prominent presence of elements such as human figures, windows, and buildings, are the most expressed experiences in the creations analyzed.



Carbonnel, C., Romero, M., & Zivny, S. (2022). The Complexity of GeneralValued Constraint Satisfaction Problems Seen from the Other Side. SIAM J. Comput., 51(1), 19–69.
Abstract: The constraint satisfaction problem (CSP) is concerned with homomorphisms between two structures. For CSPs with restricted lefthandside structures, the results of Dalmau, Languages and Programming, Springer, New York, 2007, pp. 279290] establish the precise borderline of polynomialtime solvability (subject to complexitytheoretic assumptions) and of solvability by boundedconsistency algorithms (unconditionally) as bounded treewidth modulo homomorphic equivalence. The generalvalued constraint satisfaction problem (VCSP) is a generalization of the CSP concerned with homomorphisms between two valued structures. For VCSPs with restricted lefthandside valued structures, we establish the precise borderline of polynomialtime solvability (subject to complexitytheoretic assumptions) and of solvability by the kth level of the SheraliAdams LP hierarchy (unconditionally). We also obtain results on related problems concerned with finding a solution and recognizing the tractable cases; the latter has an application in database theory.



Carrasco, P., & Hernandez, R. (2023). Schwarzian derivative for convex mappings of order a. Anal. Math. Phys., 13(2), 22.
Abstract: The main purpose of this paper is to obtain sharp bounds of the norm of Schwarzian derivative for convex mappings of order alpha in terms of the value of f '' (0), in particular, when this quantity is equal to zero. In addition, we obtain sharp bounds for distortion and growth for this mappings and we generalize the results obtained by Suita (J Hokkaido Univ Ed Sect II A 46(2):113117, 1996) and Yamashita (Hokkaido Math J 28:217230, 1999) for this particular case.



Chen, Y., Bo Liu, B., Luo, Y., MartinezVillalobos, C., Guoyu Ren, G., Huang, Y., et al. (2023). Relative Contribution of Moisture Transport during TCActive and TCInactive Periods to the Precipitation in Henan Province of North China: Mean State and an Extreme Event. J. Clim., 36(11), 3611–3623.
Abstract: A Lagrangian model—the Hybrid SingleParticle Lagrangian Integrated Trajectory model (HYSPLIT)—is used to quantify changes in moisture sources and paths for precipitation over North China’s Henan Province associated with tropical cyclone (TC) over the western North Pacific (WNP) during July–August of 1979–2021. During TCactive periods, an anomalous cyclone over the WNP enhances southeasterly and reduces southwesterly moisture transport to Henan. Accordingly, compared to TCinactive periods, moisture contributions from the Pacific Ocean (PO), eastern China (EC), and the local area (Local) are significantly enhanced by 48.32% (16.73% versus 11.28%), 20.42% (9.44% versus 7.84%), and 2.89% (4.91% versus 4.77%), respectively, while moisture contributions from the Indian Ocean (IO), Southwestern China (SWC), Eurasia (EA), and the South China Sea (SCS) are significantly reduced by −31.90% (8.61% versus 12.64%), −16.27% (4.60% versus 5.50%), −8.81% (19.10% versus 20.95%), and −6.92% (12.18% versus 13.09%). Furthermore, the moisture transport for a catastrophic extreme rainfall event during 17–22 July (“21⋅7” event) influenced by Typhoon Infa is investigated. Compared to the mean state during TCactive periods, the moisture contribution from the PO was substantially increased by 126.32% (37.87% versus 16.73%), while that from IO significantly decreased by −98.26% (0.15% versus 8.61%) during the “21⋅7” event. Analyses with a bootstrap resampling method show that moisture contributions from the PO fall outside the +6σ range, for both the TCactive and TCinactive probability distributions. Thus, the “21⋅7” event is rare and extreme in terms of the moisture contribution from the PO, with the occurrence probability being less than 1 in 1 million times.
Significance Statement
Henan, one of the most populated provinces in China, experienced a catastrophic extreme precipitation event in July 2021 (the “21⋅7” event), coinciding with the activity of a tropical cyclone (TC) over the western North Pacific, which helps establish the moisture channel. Using a Lagrangian model, we provide a better understanding of how moisture transport changes associated with TC for the mean state of 1979–2021, and reveal how extreme is the moisture transport for the “21⋅7” event with the bootstrap technique. It is found that during active TC periods, the moisture contribution from the Pacific Ocean (the Indian Ocean) is significantly enhanced (reduced). For every 1 000 000 sixday events, less than one instance like the “21⋅7” event should be expected.



Cheng, Y. C., Watari, T., Seccatore, J., Nakajima, K., Nansai, K., & Takaoka, M. (2023). A review of gold production, mercury consumption, and emission in artisanal and smallscale gold mining (ASGM). Resour. Policy, 81, 103370.
Abstract: Artisanal and smallscale gold mining (ASGM) is one of the largest sources of Hg emissions and is critical for addressing the Hg problem. Due to scarce and punctual statistics provided by governments and agencies, there is almost no accurate data on ASGM production, Hg use, and emissions. In this study, we surveyed different approaches to estimate ASGM production and collected data from different sources, including academic papers and technical reports. Globally, 380870 tonnes of gold is produced by ASGM each year, with a median value of 520 tonnes. The Hg use in the ASGM sector was estimated to be 6401000 tonnes each year, with a median value of 892 tonnes. Consequently, 248838 tonnes of Hg are emitted from the ASGM sector each year, with a median value of 615 tonnes. However, significant discrepancies were found in the data calculated using different approaches, particularly in countries where the estimates were large, such as China. To obtain a more accurate picture of global ASGM activities, a general estimation approach combining specific studies of dominant countries is necessary. For better management of ASGM in the future, developing a solid baseline and comprehensive future projection scenarios and establishing international collaboration to construct guidance on ASGM are recommended.



Concha, M., & Ruz, G. A. (2023). Evaluation of Atmospheric Environmental Regulations: The Case of Thermoelectric Power Plants. Atmosphere, 14(2), 358.
Abstract: In Chile, the concept of sacrifice zones corresponds to those land surfaces in which industrial development was prioritized over the environmental impact that it caused. A high number of industries that emit pollutants into the environment are concentrated in these zones. This paper studies the atmospheric component of the Environmental Impact Declaration and Assessment�s (EID and EIA, respectively) environmental assessment instruments of the thermoelectric power plants in northern Chile, based on their consistency with current environmental quality regulations. We specify concepts on air quality, atmospheric emission regulations, and the critical parameters and factors to be considered when carrying out an environmental impact assessment. Finally, we end by presenting possible alternatives to replace the current methodologies and criteria for atmospheric regulation in areas identified as saturated or of environmental sacrifice, with an emphasis on both population health and an environmental approach.



Efraimidis, I., Hernandez, R., & Martin, M. J. (2023). AhlforsWeill extensions for harmonic mappings. J. Math. Anal. Appl., 523(2), 127053.
Abstract: We provide two new formulas for quasiconformal extension to C for harmonic mappings defined in the unit disk and having sufficiently small Schwarzian derivative. Both are generalizations of the AhlforsWeill extension for holomorphic functions.(c) 2023 Elsevier Inc. All rights reserved.



Escobar, C., Vargas, F. J., Peters, A. A., & Carvajal, G. (2023). A Cooperative Control Algorithm for Line and Predecessor Following Platoons Subject to Unreliable Distance Measurements. Mathematics, 11(4), 801.
Abstract: This paper uses a linefollowing approach to study the longitudinal and lateral problems in vehicle platooning. Under this setup, we assume that intervehicle distance sensing is unreliable and propose a cooperative control strategy to render the platoon less vulnerable to these sensing difficulties. The proposed control scheme uses the velocity of the predecessor vehicle, communicated through a VehicletoVehicle technology, to avoid significant oscillations in the local speed provoked by tracking using unreliable local distance measurements. We implement the proposed control algorithm in the RUPU platform, a lowcost experimental platform with wireless communication interfaces that enable the implementation of cooperative control schemes for mobile agent platooning. The experiments show the effectiveness of the proposed cooperative control scheme in maintaining a suitable performance even when subject to temporal distortions in local measurements, which, in the considered experimental setup, arise from losing the lineofsight of the local sensors in paths with closed curves.

