@article{14734, abstract = {Developing cost-effective and high-performance thermoelectric (TE) materials to assemble efficient TE devices presents a multitude of challenges and opportunities. Cu3SbSe4 is a promising p-type TE material based on relatively earth abundant elements. However, the challenge lies in its poor electrical conductivity. Herein, an efficient and scalable solution-based approach is developed to synthesize high-quality Cu3SbSe4 nanocrystals doped with Pb at the Sb site. After ligand displacement and annealing treatments, the dried powders are consolidated into dense pellets, and their TE properties are investigated. Pb doping effectively increases the charge carrier concentration, resulting in a significant increase in electrical conductivity, while the Seebeck coefficients remain consistently high. The calculated band structure shows that Pb doping induces band convergence, thereby increasing the effective mass. Furthermore, the large ionic radius of Pb2+ results in the generation of additional point and plane defects and interphases, dramatically enhancing phonon scattering, which significantly decreases the lattice thermal conductivity at high temperatures. Overall, a maximum figure of merit (zTmax) ≈ 0.85 at 653 K is obtained in Cu3Sb0.97Pb0.03Se4. This represents a 1.6-fold increase compared to the undoped sample and exceeds most doped Cu3SbSe4-based materials produced by solid-state, demonstrating advantages of versatility and cost-effectiveness using a solution-based technology.}, author = {Wan, Shanhong and Xiao, Shanshan and Li, Mingquan and Wang, Xin and Lim, Khak Ho and Hong, Min and Ibáñez, Maria and Cabot, Andreu and Liu, Yu}, issn = {2366-9608}, journal = {Small Methods}, number = {8}, publisher = {Wiley}, title = {{Band engineering through Pb-doping of nanocrystal building blocks to enhance thermoelectric performance in Cu3SbSe4}}, doi = {10.1002/smtd.202301377}, volume = {8}, year = {2024}, } @article{15314, abstract = {Development of electroactive materials exhibiting high performance with superior stability is crucial in the field of supercapacitors and battery research. We report on synthesis of highly stable composite of semi-polycrystalline polyaniline and graphene (SPani-graphene) and its application in supercapacitor electrodes. The electrochemical behavior and device performance of the electrodes were investigated through cyclic voltammetry (CV), galvanostatic charge-discharge GCD) and electrochemical impedance spectroscopy (EIS) in a 3-electrode and a 2-electrode (device) cell configurations, repectively. The cell specific capacitance (Cell Csp) achieved from the 2-electrode symmetric cell configuration was 525.5 F g−1 at 0.1 A g−1 using polymer gel electrolyte (PGE). The PGE in this work is xanthan gum jellied in 1 M aq. Na2SO4. The maximum energy density and power density achieved from the device was 46.7 Wh kg−1 and 16.16 kW kg−1, respectively, at 0.4 A g−1. Furthermore, the device exhibits an excellent retention of cell specific capacitance and coulombic efficiency of 97 % and 94 %, respectively, over 10,000 continuous GCD cycles, indicating an excellent rate capability as well as a promising power management. To investigate the material's electrochemical durability, a detailed EIS study has been carried out using both, 3-electrode, and 2-electrode cell configurations, before and after long cycling test (over 10,000 continuous GCD cycles). Our thorough experimentation delivers satisfactory results and has been explained in detail in the manuscript. Hereby, we propose that the EIS technique can be adopted for investigating materials' electrochemical stability, in addition to long CV and GCD cycles in the field of supercapacitors and battery research.}, author = {Mahato, Neelima and Singh, Saurabh and Sreekanth, T. V.M. and Yoo, Kisoo and Kim, Jonghoon}, issn = {2352-152X}, journal = {Journal of Energy Storage}, publisher = {Elsevier}, title = {{Polycrystalline phases engineered in-situ in polyaniline-graphene composite evoluting an exceptional stability and high charge storage capacity: An EIS investigative approach to evaluate material's stability}}, doi = {10.1016/j.est.2024.111464}, volume = {88}, year = {2024}, } @article{15166, abstract = {Reducing defects boosts room-temperature performance of a thermoelectric device}, author = {Navita, Navita and Ibáñez, Maria}, issn = {1095-9203}, journal = {Science}, number = {6688}, pages = {1184}, publisher = {American Association for the Advancement of Science}, title = {{Electron highways are cooler}}, doi = {10.1126/science.ado4077}, volume = {383}, year = {2024}, } @article{17412, abstract = {The electroreduction of biomass-derived benzaldehyde (BZH) provides a potentially cost-effective route to produce benzyl alcohol (BA). This reaction competes with the electrochemical self-coupling of BZH to hydrobenzoin (HDB), which holds significance as a biofuel. Herein, we demonstrate the selectivity towards one or the other product strongly depends on the surface chemistry of the catalyst, specifically on its ability to adsorb hydrogen, as showcased with Cu2S electrocatalysts. We particularly analyze the effect of surface ligands, oleylamine (OAm), on the selective conversion of BZH to BA or HDB. The effect of the electrode potential, electrolyte pH, and temperature are studied. Results indicate that bare Cu2S exhibits higher selectivity towards BA, while OAm-capped Cu2S promotes HDB formation. This difference is explained by the competing adsorption of protons and BZH. During the BZH electrochemical conversion, electrons first transfer to the C in the C[double bond, length as m-dash]O group to form a ketyl radical. Then the radical either couples with surrounding H+ to form BA or self-couple to produce HDB, depending on the H+ availability that is affected by the electrocatalyst surface properties. The presence of OAm inhibits the H adsorption on the electrode surface therefore reducing the formation of high-energy state Had and its combination with ketyl radicals to form BA. Instead, the presence of OAm promotes the outer sphere reaction for obtaining HDB.}, author = {Gong, Li and Zhao, Shiling and Yu, Jing and Li, Junshan and Arbiol, Jordi and Kallio, Tanja and Calcabrini, Mariano and Martínez-Alanis, Paulina R. and Ibáñez, Maria and Cabot, Andreu}, issn = {2753-1457}, journal = {Energy Advances}, number = {9}, pages = {2287--2294}, publisher = {Royal Society of Chemistry}, title = {{Influence of the catalyst surface chemistry on the electrochemical self-coupling of biomass-derived benzaldehyde into hydrobenzoin}}, doi = {10.1039/d4ya00334a}, volume = {3}, year = {2024}, } @article{17897, abstract = {High-entropy materials (HEMs) offer a quasi-continuous spectrum of active sites and have generated great expectations in fields such as electrocatalysis and energy storage. Despite their potential, the complex composition and associated surface phenomena of HEMs pose challenges to their rational design and development. In this context, we have synthesized FeCoNiPdWP high entropy phosphide (HEP) nanoparticles using a low-temperature colloidal method, and explored their application as bifunctional electrocatalysts for the oxygen evolution and reduction reactions (OER/ORR). Our analysis provides a detailed understanding of the individual roles and transformations of each element during OER/ORR operation. Notably, the HEPs exhibit an exceptionally low OER overpotential of 227 mV at 10 mA cm−2, attributed to the reconstructed HEP surface into a FeCoNiPdW high entropy oxyhydroxide with high oxidation states of Fe, Co, and Ni serving as the active sites. Additionally, Pd and W play crucial roles in modulating the electronic structure to optimize the adsorption energy of oxygen intermediates. For the ORR, Pd emerges as the most active component. In the reconstructed catalyst, the strong d–d orbital coupling of especially Pd, Co, and W fine-tunes ORR electron transfer pathways, delivering an ORR half-wave potential of 0.81 V with a pure four-electron reduction mechanism. The practicality of these HEPs catalysts is showcased through the assembly of aqueous zinc–air batteries. These batteries demonstrate a superior specific capacity of 886 mA h gZn−1 and maintain excellent stability over more than 700 hours of continuous operation. Overall, this study not only elucidates the role of each element in HEMs but also establishes a foundational framework for the design and development of next-generation bifunctional oxygen catalysts, broadening the potential applications of these complex materials in advanced energy systems.}, author = {He, Ren and Wang, Shiqi and Yang, Linlin and Horta, Sharona and Ding, Yang and Di, Chong and Zhang, Xuesong and Xu, Ying and Ibáñez, Maria and Zhou, Yingtang and Mebs, Stefan and Dau, Holger and Hausmann, Jan Niklas and Huo, Wenyi and Menezes, Prashanth W. and Cabot, Andreu}, issn = {1754-5706}, journal = {Energy and Environmental Science}, number = {19}, pages = {7193--7208}, publisher = {Royal Society of Chemistry}, title = {{Active site switching on high entropy phosphides as bifunctional oxygen electrocatalysts for rechargeable/robust Zn-air battery}}, doi = {10.1039/d4ee01912a}, volume = {17}, year = {2024}, } @article{17125, abstract = {We explore the potential of nanocrystals (a term used equivalently to nanoparticles) as building blocks for nanomaterials, and the current advances and open challenges for fundamental science developments and applications. Nanocrystal assemblies are inherently multiscale, and the generation of revolutionary material properties requires a precise understanding of the relationship between structure and function, the former being determined by classical effects and the latter often by quantum effects. With an emphasis on theory and computation, we discuss challenges that hamper current assembly strategies and to what extent nanocrystal assemblies represent thermodynamic equilibrium or kinetically trapped metastable states. We also examine dynamic effects and optimization of assembly protocols. Finally, we discuss promising material functions and examples of their realization with nanocrystal assemblies.}, author = {Bassani, Carlos L. and Van Anders, Greg and Banin, Uri and Baranov, Dmitry and Chen, Qian and Dijkstra, Marjolein and Dimitriyev, Michael S. and Efrati, Efi and Faraudo, Jordi and Gang, Oleg and Gaston, Nicola and Golestanian, Ramin and Guerrero-Garcia, G. Ivan and Gruenwald, Michael and Haji-Akbari, Amir and Ibáñez, Maria and Karg, Matthias and Kraus, Tobias and Lee, Byeongdu and Van Lehn, Reid C. and Macfarlane, Robert J. and Mognetti, Bortolo M. and Nikoubashman, Arash and Osat, Saeed and Prezhdo, Oleg V. and Rotskoff, Grant M. and Saiz, Leonor and Shi, An Chang and Skrabalak, Sara and Smalyukh, Ivan I. and Tagliazucchi, Mario and Talapin, Dmitri V. and Tkachenko, Alexei V. and Tretiak, Sergei and Vaknin, David and Widmer-Cooper, Asaph and Wong, Gerard C.L. and Ye, Xingchen and Zhou, Shan and Rabani, Eran and Engel, Michael and Travesset, Alex}, issn = {1936-086X}, journal = {ACS Nano}, number = {23}, pages = {14791--14840}, publisher = {American Chemical Society}, title = {{Nanocrystal assemblies: Current advances and open problems}}, doi = {10.1021/acsnano.3c10201}, volume = {18}, year = {2024}, } @article{17896, abstract = {Broadband photodetectors that can decipher the wavelength (λ) and intensity (I) of an unknown incident light are urgently demanded. Photothermoelectric (PTE) detectors can achieve ultrabroadband photodetection surpassing the bandgap limitation; however, their practical application is severely hampered by the lack of deciphering strategy. In this work, we report a variable elimination method to decipher λ and I of the incident lights based on an integrated Ag2Se film-based PTE detector. Nanostructured Ag2Se films with controlled thickness are synthesized using an ion sputtering of Ag and a room-temperature selenization method and then assembled into a detector. Under identical illumination, Ag2Se films of different thicknesses produce varying output photothermal voltages, influenced by factors including λ. By establishing a direct relationship between the photothermal voltage and the absorption of Ag2Se films of varied thickness, we successfully eliminate variables independent of λ, thus determining λ. Subsequently, I is determined by the calibrated responsivity relationship using obtained λ. Our PTE detector achieves a broadband spectrum from 400 to 950 nm and high accuracy, with deviations as low as ∼2.63 and ∼0.53% for deciphered λ and I, respectively. This method allows for self-powered broadband decipherable photodetection without a complex device architecture or computational assistance, which could boost the research enthusiasm and promote the commercialization of PTE broadband detectors.}, author = {Zhou, Jiamin and Xu, Shengduo and Shuai, Yi and Sun, Qiang and Ma, Huangshui and Wang, Chao and Wu, Haijuan and Tan, Shanshan and Wang, Zegao and Yang, Lei}, issn = {1944-8252}, journal = {ACS Applied Materials and Interfaces}, number = {36}, pages = {47923--47930}, publisher = {American Chemical Society}, title = {{Decipher the wavelength and intensity using photothermoelectric detectors}}, doi = {10.1021/acsami.4c10489}, volume = {16}, year = {2024}, } @article{15348, abstract = {We report on synthesis of highly crystalline polythiophene and its application in supercapacitor electrodes. The material exhibits a remarkably stable electrochemical behavior and an excellent device performance. The device delivers an electrode specific capacitance (Csp) of 129.13F g−1, Cell Csp of 32.28F g−1 at 0.5 A/g; energy, and power densities of ∼ 3 Wh kg−1 and 250 W kg -1, respectively at 0.5 A/g. Also, it exhibits an excellent retention of Cell Csp and coulombic efficiency up to ∼ 95 % over 10,000 continuous galvanostatic charge discharge (GCD) cycles indicating a remarkable performance by a standalone, pristine and undoped polythiophene. Electrochemical impedance spectroscopy (EIS) studies further suggest material’s stable capacitive behavior. The material’s enhanced electrochemical properties, stable behavior and outstanding performance in device application are attributed to the crystalline phases present in the polymer matrix achievable via a slow rate of synthesis; overall, an edge over other conventional synthesis methods.}, author = {Mahato, Neelima and Singh, Saurabh and Sreekanth, T. V.M. and Yoo, Kisoo and Kim, Jonghoon}, issn = {1873-4979}, journal = {Materials Letters}, publisher = {Elsevier}, title = {{In-situ engineered highly crystalline polythiophene empowered electrochemical capacitor-I: Synthesis, characterization, and electrochemical charge storage}}, doi = {10.1016/j.matlet.2024.136483}, volume = {365}, year = {2024}, } @article{15356, abstract = {Identifying efficient active sites for the direct synthesis of hydrogen peroxide over Pd-based catalysts has been a subject of considerable debate. In this study, we employ particle swarm optimization method and density functional theory to explore the H2O2 synthesis mechanism on Pd, PdO, and the partially oxidized surface (Pd9OX). A comprehensive mechanism for Pd9OX is elucidated, and subsequent coverage-dependent kinetic analysis allows for a quantitative assessment of catalytic performance at the interphase. Our findings conclusively establish that the interphase between Pd and PdO represents the optimal active site. Phase diagram analysis further aids in determining stable structures under reaction conditions. At 298.15 K and under oxygen balance, the Pd9O6 surface remains stable throughout the reaction, demonstrating high activity and selectivity. This work underscores the significance of the interphase in comprehending catalytic performance and unveils promising avenues for optimizing catalyst performance by controlling reaction conditions and surface composition.}, author = {Zhao, Jinyan and Yao, Zihao and Bunting, Rhys and Wang, Yaqiu and Wang, Jianguo}, issn = {0009-2509}, journal = {Chemical Engineering Science}, publisher = {Elsevier}, title = {{Identifying Pd9OX as the optimum catalyst for the direct synthesis of H2O2 through microkinetic modeling with coverage effects}}, doi = {10.1016/j.ces.2024.120199}, volume = {295}, year = {2024}, } @phdthesis{18568, abstract = {Locomotion is ubiquitous in the animal kingdom because an animal's survival depends on its ability to navigate its environment to find food, avoid predators and locate potential mates. These behaviours require control mechanisms that can extract information from the environment, particularly visual cues. Selective evolutionary pressures have thus refined such visuomotor transformations in a species-specific manner to meet the specific ecological and ethological challenges of each organism. However, a common challenge across organisms as visual information processing becomes increasingly detailed is the mechanisms required to synthesise disparate pieces of information into a coherent percept or unified picture of the world. In this thesis, I investigate how disparate visual information is combined in the brain of Drosophila melanogaster to effectively guide locomotion. For this, I first designed and built a behavioural setup to record locomotion and present visual stimuli to freely-walking fruit flies in a closed-loop manner. This setup allowed the investigation of innate visually-guided behaviours, including the optomotor reflex and courtship. Second, taking advantage of my system I investigated the optomotor response, a reflexive visual stabilisation behaviour in which flies turn in the direction of global motion to minimise retinal slip. This behaviour is thought to be mediated by Lobula plate tangential cells (LPTCs); a complex network of optic-flow-sensitive neurons essential for self-motion estimation. Using a novel genetic mutant, I demonstrate that electrical coupling between two LPTC subtypes, contralateral HS and H2 neurons, regulates the balance between smooth optomotor turning and saccadic anti-optomotor responses. These findings underscore the critical role of binocular motion cue integration in guiding course control. Finally, I developed a novel behavioural paradigm in which a sexually aroused male fruit fly is presented with an optomotor distractor. This setup creates competition between two visual behaviours, courtship tracking and the optomotor response, enabling me to explore how the visual system resolves this conflict. In this setting, males engaged in courtship selectively suppress their optomotor response based on the female's location. Furthermore, when this experiment is replicated with an “artificial female”, optogenetically aroused males alternate between tracking and optomotor responses. The probability and dynamics of this switching are determined by the relative strengths of the two competing stimuli. In summary, the results presented in this thesis explore two mechanisms – integration and competition - through which visual information is combined in the brain of the fruit fly to drive locomotion.}, author = {Satapathy, Roshan K}, isbn = {978-3-99078-047-3}, issn = {2663-337X}, pages = {114}, publisher = {Institute of Science and Technology Austria}, title = {{Mechanisms of visual integration and competition in innate behaviours in Drosophila melanogaster}}, doi = {10.15479/at:ista:18568}, year = {2024}, } @article{15182, abstract = {Thermoelectric materials convert heat into electricity, with a broad range of applications near room temperature (RT). However, the library of RT high-performance materials is limited. Traditional high-temperature synthetic methods constrain the range of materials achievable, hindering the ability to surpass crystal structure limitations and engineer defects. Here, a solution-based synthetic approach is introduced, enabling RT synthesis of powders and exploration of densification at lower temperatures to influence the material's microstructure. The approach is exemplified by Ag2Se, an n-type alternative to bismuth telluride. It is demonstrated that the concentration of Ag interstitials, grain boundaries, and dislocations are directly correlated to the sintering temperature, and achieve a figure of merit of 1.1 from RT to 100 °C after optimization. Moreover, insights into and resolve Ag2Se's challenges are provided, including stoichiometry issues leading to irreproducible performances. This work highlights the potential of RT solution synthesis in expanding the repertoire of high-performance thermoelectric materials for practical applications.}, author = {Kleinhanns, Tobias and Milillo, Francesco and Calcabrini, Mariano and Fiedler, Christine and Horta, Sharona and Balazs, Daniel and Strumolo, Marissa J. and Hasler, Roger and Llorca, Jordi and Tkadletz, Michael and Brutchey, Richard L. and Ibáñez, Maria}, issn = {1614-6840}, journal = {Advanced Energy Materials}, number = {22}, publisher = {Wiley}, title = {{A route to high thermoelectric performance: Solution‐based control of microstructure and composition in Ag2Se}}, doi = {10.1002/aenm.202400408}, volume = {14}, year = {2024}, } @article{18444, abstract = {Animals rely on compensatory actions to maintain stability and navigate their environment efficiently. These actions depend on global visual motion cues known as optic-flow. While the optomotor response has been the traditional focus for studying optic-flow compensation in insects, its simplicity has been insufficient to determine the role of the intricate optic-flow processing network involved in visual course control. Here, we reveal a series of course control behaviours in Drosophila and link them to specific neural circuits. We show that bilateral electrical coupling of optic-flow-sensitive neurons in the fly’s lobula plate are required for a proper course control. This electrical interaction works alongside chemical synapses within the HS-H2 network to control the dynamics and direction of turning behaviours. Our findings reveal how insects use bilateral motion cues for navigation, assigning a new functional significance to the HS-H2 network and suggesting a previously unknown role for gap junctions in non-linear operations.}, author = {Pokusaeva, Victoria and Satapathy, Roshan K and Symonova, Olga and Jösch, Maximilian A}, issn = {2041-1723}, journal = {Nature Communications}, publisher = {Springer Nature}, title = {{Bilateral interactions of optic-flow sensitive neurons coordinate course control in flies}}, doi = {10.1038/s41467-024-53173-w}, volume = {15}, year = {2024}, } @article{15404, abstract = {We used diverse methods to characterize the role of avian lateral spiriform nucleus (SpL) in basal ganglia motor function. Connectivity analysis showed that SpL receives input from globus pallidus (GP), and the intrapeduncular nucleus (INP) located ventromedial to GP, whose neurons express numerous striatal markers. SpL-projecting GP neurons were large and aspiny, while SpL-projecting INP neurons were medium sized and spiny. Connectivity analysis further showed that SpL receives inputs from subthalamic nucleus (STN) and substantia nigra pars reticulata (SNr), and that the SNr also receives inputs from GP, INP, and STN. Neurochemical analysis showed that SpL neurons express ENK, GAD, and a variety of pallidal neuron markers, and receive GABAergic terminals, some of which also contain DARPP32, consistent with GP pallidal and INP striatal inputs. Connectivity and neurochemical analysis showed that the SpL input to tectum prominently ends on GABAA receptor-enriched tectobulbar neurons. Behavioral studies showed that lesions of SpL impair visuomotor behaviors involving tracking and pecking moving targets. Our results suggest that SpL modulates brainstem-projecting tectobulbar neurons in a manner comparable to the demonstrated influence of GP internus on motor thalamus and of SNr on tectobulbar neurons in mammals. Given published data in amphibians and reptiles, it seems likely the SpL circuit represents a major direct pathway-type circuit by which the basal ganglia exerts its motor influence in nonmammalian tetrapods. The present studies also show that avian striatum is divided into three spatially segregated territories with differing connectivity, a medial striato-nigral territory, a dorsolateral striato-GP territory, and the ventrolateral INP motor territory.}, author = {Reiner, Anton and Medina, Loreta and Abellan, Antonio and Deng, Yunping and Toledo, Claudio A.B. and Luksch, Harald and Vega Zuniga, Tomas A and Riley, Nell B. and Hodos, William and Karten, Harvey J.}, issn = {1096-9861}, journal = {Journal of Comparative Neurology}, number = {5}, publisher = {Wiley}, title = {{Neurochemistry and circuit organization of the lateral spiriform nucleus of birds: A uniquely nonmammalian direct pathway component of the basal ganglia}}, doi = {10.1002/cne.25620}, volume = {532}, year = {2024}, } @inproceedings{18965, abstract = {A thermoelectric cooler is a solid-state device that transfers heat from one side to another when an electrical current passes through it. This technology is appealing because it can provide precise and localized cooling and heating without using hazardous liquids or gases commonly found in traditional vapor compression refrigeration. These devices are compact, customizable in size, work in any orientation, operate noiselessly, and require minimal maintenance. Even though thermoelectric coolers could be transformative for many advanced thermal management applications, their widespread adoption is hindered by the low efficiency of the thermoelectric materials and costly manufacturing processes. In this work, we use extrusion-based 3D printing techniques to fabricate high-performance thermoelectric materials using nanomaterial-based ink. The ink formulation is optimized to ensure structural integrity and particle interfacial bonding during annealing, providing p- and n-type materials with record-high zT values of 1.46 and 1.35 at room temperature, respectively. Moreover, we integrate the printed materials into a 32-pair device and achieve a significant cooling temperature gradient of 50 °C and a coefficient of performance of 3.8, comparable to best-performing thermoelectric coolers, avoiding material waste, and the energy-intense and inefficient steps, such as high-temperature synthesis, pressure-assisted sintering, and cutting and dicing ingots, commonly used in conventional manufacturing processes.}, author = {Ibáñez, Maria and Xu, Shengduo and Horta, Sharona and Lawal, Abayomi Q}, booktitle = {Proceedings of the Materials for Sustainable Development Conference}, location = {Lausanne, Switzerland}, publisher = {Fundació de la comunitat valenciana SCITO}, title = {{High-performance thermoelectric cooler fabricated vith extrusion-based 3D printing materials}}, doi = {10.29363/nanoge.matsusfall.2024.222}, year = {2024}, } @article{15163, abstract = {For some k∈Z≥0∪{∞}, we call a linear forest k-bounded if each of its components has at most k edges. We will say a (k,ℓ)-bounded linear forest decomposition of a graph G is a partition of E(G) into the edge sets of two linear forests Fk,Fℓ where Fk is k-bounded and Fℓ is ℓ-bounded. We show that the problem of deciding whether a given graph has such a decomposition is NP-complete if both k and ℓ are at least 2, NP-complete if k≥9 and ℓ=1, and is in P for (k,ℓ)=(2,1). Before this, the only known NP-complete cases were the (2,2) and (3,3) cases. Our hardness result answers a question of Bermond et al. from 1984. We also show that planar graphs of girth at least nine decompose into a linear forest and a matching, which in particular is stronger than 3-edge-colouring such graphs.}, author = {Campbell, Rutger and Hörsch, Florian and Moore, Benjamin}, issn = {0012-365X}, journal = {Discrete Mathematics}, number = {6}, publisher = {Elsevier}, title = {{Decompositions into two linear forests of bounded lengths}}, doi = {10.1016/j.disc.2024.113962}, volume = {347}, year = {2024}, } @article{18937, abstract = {A detailed structural, magnetic as well as dielectric dynamics study is carried out to investigate the influence of Bi3+ on YCrO3. All the samples crystalize in orthorhombic structure with Pnma symmetry and the grains are mostly stretched with Bi. A coexisting tunable fraction of both antiferromagnetic (AFM) and weak ferromagnetic (WFM) phases is acquired by the system down to Low-T. An abnormal negative magnetization in zero field is correlated to the competition among AFM and WFM phases. Maximum magnetization decreases while the coercivity first increases and then decreases with Bi is correlated to the competing effect between the local deformation and Cr–O–Cr exchange interaction. The magnetodielectric coupling with improved permittivity might be associated with the 6s2 lone pair electron of Bi3+. Furthermore, ac-conductivity increases with a decrease in activation energy (0.27–0.11 eV), is explained in the framework of structural model and charge carrier hopping between Cr3+ and Cr4+ ions.}, author = {Ray, Sujata Kumari and Pati, Anupama and Sahoo, Payala and Sahoo, A.K. and Singh, Saurabh and Takeuchi, Tsunehiro and Dash, S.}, issn = {0921-4526}, journal = {Physica B: Condensed Matter}, publisher = {Elsevier}, title = {{Tunable magnetoelectronic properties in Bi3+ substituted YCrO3}}, doi = {10.1016/j.physb.2024.416018}, volume = {685}, year = {2024}, } @misc{17488, abstract = {Behavioural data for Pokusaeva, Satapathy et al. Relevant information can be found in the 'README.txt' file.}, author = {Satapathy, Roshan K and Jösch, Maximilian A and Symonova, Olga and Pokusaeva, Victoria}, keywords = {drosophila, behaviour, locomotion, gap junctions}, publisher = {Institute of Science and Technology Austria}, title = {{Bilateral interactions of optic-flow sensitive neurons coordinate course control in flies}}, doi = {10.15479/AT:ISTA:17488}, year = {2024}, } @inproceedings{18758, abstract = {MaxCut is a classical NP-complete problem and a crucial building block in many combinatorial algorithms. The famous Edwards-Erdős bound states that any connected graph on n vertices with m edges contains a cut of size at least m/2+(n-1)/4. Crowston, Jones and Mnich [Algorithmica, 2015] showed that the MaxCut problem on simple connected graphs admits an FPT algorithm, where the parameter k is the difference between the desired cut size c and the lower bound given by the Edwards-Erdős bound. This was later improved by Etscheid and Mnich [Algorithmica, 2017] to run in parameterized linear time, i.e., f(k)⋅ O(m). We improve upon this result in two ways: Firstly, we extend the algorithm to work also for multigraphs (alternatively, graphs with positive integer weights). Secondly, we change the parameter; instead of the difference to the Edwards-Erdős bound, we use the difference to the Poljak-Turzík bound. The Poljak-Turzík bound states that any weighted graph G has a cut of size at least (w(G))/2+(w_MSF(G))/4, where w(G) denotes the total weight of G, and w_MSF(G) denotes the weight of its minimum spanning forest. In connected simple graphs the two bounds are equivalent, but for multigraphs the Poljak-Turzík bound can be larger and thus yield a smaller parameter k. Our algorithm also runs in parameterized linear time, i.e., f(k)⋅ O(m+n).}, author = {Lill, Jonas and Petrova, Kalina H and Weber, Simon}, booktitle = {19th International Symposium on Parameterized and Exact Computation}, isbn = {9783959773539}, issn = {1868-8969}, location = {Egham, United Kingdom}, publisher = {Schloss Dagstuhl - Leibniz-Zentrum für Informatik}, title = {{Linear-time MaxCut in multigraphs parameterized above the Poljak-Turzík bound}}, doi = {10.4230/LIPIcs.IPEC.2024.2}, volume = {321}, year = {2024}, } @article{18583, abstract = {There are a number of well-known problems and conjectures about partitioning graphs to satisfy local constraints. For example, the majority colouring conjecture of Kreutzer, Oum, Seymour, van der Zypen and Wood states that every directed graph has a 3-colouring such that for every vertex v, at most half of the out-neighbours of v have the same colour as . As another example, the internal partition conjecture, due to DeVos and to Ban and Linial, states that for every d, all but finitely many d-regular graphs have a partition into two non-empty parts such that for every vertex v, at least half of the neighbours of v lie in the same part as v. We prove several results in this spirit: in particular, two of our results are that the majority colouring conjecture holds for Erdős–Rényi random directed graphs (of any density), and that the internal partition conjecture holds if we permit a tiny number of ‘exceptional vertices’. Our proofs involve a variety of techniques, including several different methods to analyse random recolouring processes. One highlight is a personality-changing scheme: we ‘forget’ certain information based on the state of a Markov chain, giving us more independence to work with.}, author = {Anastos, Michael and Cooley, Oliver and Kang, Mihyun and Kwan, Matthew Alan}, issn = {1469-7750}, journal = {Journal of the London Mathematical Society}, number = {6}, publisher = {Wiley}, title = {{Partitioning problems via random processes}}, doi = {10.1112/jlms.70010}, volume = {110}, year = {2024}, } @article{17376, abstract = {The inertia bound and ratio bound (also known as the Cvetković bound and Hoffman bound) are two fundamental inequalities in spectral graph theory, giving upper bounds on the independence number α(G) of a graph G in terms of spectral information about a weighted adjacency matrix of G. For both inequalities, given a graph G, one needs to make a judicious choice of weighted adjacency matrix to obtain as strong a bound as possible. While there is a well-established theory surrounding the ratio bound, the inertia bound is much more mysterious, and its limits are rather unclear. In fact, only recently did Sinkovic find the first example of a graph for which the inertia bound is not tight (for any weighted adjacency matrix), answering a longstanding question of Godsil. We show that the inertia bound can be extremely far from tight, and in fact can significantly underperform the ratio bound: for example, one of our results is that for infinitely many n, there is an n-vertex graph for which even the unweighted ratio bound can prove α(G)≤4n3/4, but the inertia bound is always at least n/4. In particular, these results address questions of Rooney, Sinkovic, and Wocjan--Elphick--Abiad.}, author = {Kwan, Matthew Alan and Wigderson, Yuval}, issn = {1469-2120}, journal = {Bulletin of the London Mathematical Society}, number = {10}, pages = {3196--3208}, publisher = {London Mathematical Society}, title = {{The inertia bound is far from tight}}, doi = {10.1112/blms.13127}, volume = {56}, year = {2024}, }