645 results on '"Bojko P"'
Search Results
2. Braided Logarithmic Vertex Algebras
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Bakalov, Bojko and Villarreal, Juan J.
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Mathematics - Quantum Algebra ,Mathematical Physics ,Primary 17B69, Secondary 17B63, 81R10, 81T40 - Abstract
We study a family of algebras defined using a locally-finite endomorphism called a braiding map. When the braiding map is semi-simple, the algebra is a generalized vertex algebra, while when the braiding map is locally-nilpotent we have a logarithmic vertex algebra. We describe a method that associates to these algebras non-local Poisson vertex algebras, and we use this relation to build a new example of a generalized vertex algebra motivated by the non-linear Schr\"odinger non-local Poisson vertex algebra
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- 2024
3. Geometric Quantum Machine Learning with Horizontal Quantum Gates
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Wiersema, Roeland, Kemper, Alexander F., Bakalov, Bojko N., and Killoran, Nathan
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Quantum Physics - Abstract
In the current framework of Geometric Quantum Machine Learning, the canonical method for constructing a variational ansatz that respects the symmetry of some group action is by forcing the circuit to be equivariant, i.e., to commute with the action of the group. This can, however, be an overzealous constraint that greatly limits the expressivity of the circuit, especially in the case of continuous symmetries. We propose an alternative paradigm for the symmetry-informed construction of variational quantum circuits, based on homogeneous spaces, relaxing the overly stringent requirement of equivariance. We achieve this by introducing horizontal quantum gates, which only transform the state with respect to the directions orthogonal to those of the symmetry. We show that horizontal quantum gates are much more expressive than equivariant gates, and thus can solve problems that equivariant circuits cannot. For instance, a circuit comprised of horizontal gates can find the ground state of an $\mathrm{SU}(2)$-symmetric model where the ground state spin sector is unknown--a task where equivariant circuits fall short. Moreover, for a particular subclass of horizontal gates based on symmetric spaces, we can obtain efficient circuit decompositions for our gates through the KAK theorem. Finally, we highlight a particular class of horizontal quantum gates that behave similarly to general $\mathrm{SU}(4)$ gates, while achieving a quadratic reduction in the number of parameters for a generic problem.
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- 2024
4. Logarithmic Vertex Algebras
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Bakalov, Bojko N. and Villarreal, Juan J.
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- 2024
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5. CBCT-based online adaptive radiotherapy of the prostate bed: first clinical experience and comparison to nonadaptive conventional IGRT
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Fischer, J., Fischer, L. A., Bensberg, J., Bojko, N., Bouabdallaoui, M., Frohn, J., Hüttenrauch, P., Tegeler, K., Wagner, D., Wenzel, A., Schmitt, D., Guhlich, M., Leu, M., El Shafie, R., Stamm, G., Schilling, A.-F., Dröge, L. H., and Rieken, S.
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- 2024
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6. Microsporidia and invertebrate hosts: genome-informed taxonomy surrounding a new lineage of crayfish-infecting Nosema spp. (Nosematida)
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Stratton, Cheyenne E., Bolds, Sara A., Reisinger, Lindsey S., Behringer, Donald C., Khalaf, Amjad, and Bojko, Jamie
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- 2024
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7. Decapod fisheries and parasite species richness: an exploration of host traits and parasitic influence
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Duermit-Moreau, Elizabeth, Bojko, Jamie, Siders, Zachary A., Stephens, Natalie C., and Behringer, Donald C.
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- 2024
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8. Reconstruction of Vertex Algebras in Even Higher Dimensions
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Bakalov, Bojko N. and Nikolov, Nikolay M.
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- 2024
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9. Invisible invaders: range expansion of feral Neocaridina davidi offers new opportunities for generalist intracellular parasites
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Prati, Sebastian, Grabner, Daniel S., Hupało, Kamil, Weiperth, András, Maciaszek, Rafał, Lipták, Boris, Bojko, Jamie, Bérces, Fanni, and Sures, Bernd
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- 2024
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10. Universal Virasoro constraints for quivers with relations
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Bojko, Arkadij
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Mathematics - Algebraic Geometry ,Mathematics - Representation Theory - Abstract
Following our reformulation of sheaf-theoretic Virasoro constraints with applications to curves and surfaces joint with Lim-Moreira, I describe in the present work the quiver analog. After phrasing a universal approach to Virasoro constraints for moduli of quiver-representations, I prove them for any finite quiver with relations, with frozen vertices, but without cycles. I use partial flag varieties which are special cases of moduli spaces of framed representations as a guiding example throughout. These results are applied to give an independent proof of Virasoro constraints for all Gieseker semistable sheaves on $\mathbb{P}^2$ and $\mathbb{P}^1 \times \mathbb{P}^1$ by using derived equivalences to quivers with relations. Combined with an existing universality argument for Virasoro constraints on Hilbert schemes of points on surfaces, this leads to the proof of this rank 1 case for any $S$ which is independent of the previous results in Gromov-Witten theory., Comment: Misclicked on the recently added feature to upload previously used files. This is the correct version 3 of the article
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- 2023
11. Classification of dynamical Lie algebras of 2-local spin systems on linear, circular and fully connected topologies
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Wiersema, Roeland, Kökcü, Efekan, Kemper, Alexander F., and Bakalov, Bojko N.
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- 2024
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12. A Lie algebraic theory of barren plateaus for deep parameterized quantum circuits
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Ragone, Michael, Bakalov, Bojko N., Sauvage, Frédéric, Kemper, Alexander F., Ortiz Marrero, Carlos, Larocca, Martín, and Cerezo, M.
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- 2024
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13. Doxycycline reduces liver and kidney injuries in a rat hemorrhagic shock model
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Sordi, Regina, Bojko, Luana, Oliveira, Filipe R. M. B., Rosales, Thiele Osvaldt, Souza, Camila Fernandes, Moreno, Lucas Wenceslau, Ferreira Alves, Gustavo, Vellosa, José Carlos Rebuglio, Fernandes, Daniel, and Gomes, Jose Rosa
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- 2024
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14. Agricultural legacy shapes plant diversity patterns in mountain grasslands of Maramureș and Bukovina: A cross‐border perspective (Ukraine, Romania)
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Monika Janišová, Martin Magnes, Igor Bojko, Liubov M. Borsukevych, Vasyl V. Budzhak, Illya Chorney, Anamaria Iuga, Cosmin Marius Ivașcu, Roman Kish, Anna Kuzemko, Salza Palpurina, Katarína Skokanová, Pavel Širka, Alla Tokaryuk, and Polina Dayneko
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agricultural policy ,bryophyte ,grassland management ,Romania ,species richness ,traditional farming ,Human ecology. Anthropogeography ,GF1-900 ,Ecology ,QH540-549.5 - Abstract
Abstract We investigated farming practices and grassland plant diversity patterns in the historical regions of Maramureș and Bukovina, located in the central Eastern Carpathians of Romania and Ukraine. We explored the influence of social and historical factors on recent grassland plant diversity, including changes and modifications in land use and grassland management practices. We used stratified random sampling to select 48 grassland parcels in eight villages on the Ukrainian‐Romanian borderlands. We identified the factors that affect the composition and diversity of grassland vascular plants and bryophytes at multiple spatial scales and compared the frequency and timing of historical and recent grassland management practices to distinguish between preserved and modified agricultural traditions. In most of the grassland parcels studied (83% in Romania and 78% in Ukraine), traditional land use persisted. Local plant species richness was primarily influenced by management practices, outweighing the impact of topography and soil factors. Regular mowing at appropriate intensity increased the richness of vascular plants, while grazing promoted the richness of bryophyte species. Modifications to farming systems, observed in all studied villages, were mainly due to declining population and livestock numbers. Although the timing of spring and autumn grazing in hay meadows still adhered to tradition, mowing schedules shifted earlier, especially for the first cut of two‐cut hay meadows. Traditional corralling, fertilization and hayseed application have become rare or discontinued in certain villages, while controlled burning has increased. Past use of mineral fertilizers in Ukrainian villages during the Soviet era influenced the recent diversity and composition of vascular plant species, favouring nutrient‐demanding species. Social factors and agricultural policies indirectly affect biodiversity in semi‐natural grasslands, leaving a tangible footprint even in the most remote areas of the Carpathian Mountains. We provide basic recommendations to preserve the remarkable biodiversity of the region. Read the free Plain Language Summary for this article on the Journal blog.
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- 2024
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15. Advantages of Ultrafast™ ultrasound in the screening for renal artery disease
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Ivanac Gordana, Bulum Antonio, Jagnjić Ana Bojko, Vujević Filip, Lucijanić Marko, Bulum Marta, Ivanac Krešimir, Brkljačić Boris, and Divjak Eugen
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imaging ,doppler ultrasound ,ultrafast ,renal artery disease ,Medicine (General) ,R5-920 ,Medical technology ,R855-855.5 - Abstract
Renal artery disease is the most common cause of secondary hypertension worldwide. B-mode and Doppler ultrasound are considered the modalities of choice for the imaging of the renal arteries. However, an adequate examination can be plagued by difficulties in patients with unfavorable anatomy. UltraFast™ ultrasound is faster, performed with higher frame rates, and enables prospective and retrospective data analysis with quantification of flow data in the obtained image, so it may be able to resolve some of the difficulties encountered during conventional ultrasound examinations in patients with suspected renal artery disease.
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- 2024
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16. Classification of dynamical Lie algebras of 2-local spin systems on linear, circular and fully connected topologies
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Roeland Wiersema, Efekan Kökcü, Alexander F. Kemper, and Bojko N. Bakalov
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Physics ,QC1-999 ,Electronic computers. Computer science ,QA75.5-76.95 - Abstract
Abstract Much is understood about 1-dimensional spin chains in terms of entanglement properties, physical phases, and integrability. However, the Lie algebraic properties of the Hamiltonians describing these systems remain largely unexplored. In this work, we provide a classification of all Lie algebras generated by the terms of 2-local spin chain Hamiltonians, or so-called dynamical Lie algebras, on 1-dimensional linear and circular lattice structures. We find 17 unique dynamical Lie algebras. Our classification includes some well-known models such as the transverse-field Ising model and the Heisenberg chain, and we also find more exotic classes of Hamiltonians that appear new. In addition to the closed and open spin chains, we consider systems with a fully connected topology, which may be relevant for quantum machine learning approaches. We discuss the practical implications of our work in the context of variational quantum computing, quantum control and the spin chain literature.
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- 2024
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17. A Lie Algebraic Theory of Barren Plateaus for Deep Parameterized Quantum Circuits
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Ragone, Michael, Bakalov, Bojko N., Sauvage, Frédéric, Kemper, Alexander F., Marrero, Carlos Ortiz, Larocca, Martin, and Cerezo, M.
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Quantum Physics - Abstract
Variational quantum computing schemes train a loss function by sending an initial state through a parametrized quantum circuit, and measuring the expectation value of some operator. Despite their promise, the trainability of these algorithms is hindered by barren plateaus (BPs) induced by the expressiveness of the circuit, the entanglement of the input data, the locality of the observable, or the presence of noise. Up to this point, these sources of BPs have been regarded as independent. In this work, we present a general Lie algebraic theory that provides an exact expression for the variance of the loss function of sufficiently deep parametrized quantum circuits, even in the presence of certain noise models. Our results allow us to understand under one framework all aforementioned sources of BPs. This theoretical leap resolves a standing conjecture about a connection between loss concentration and the dimension of the Lie algebra of the circuit's generators., Comment: 11+17 pages, 2+2 figures, updated manuscript and title to published version
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- 2023
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18. Classification of dynamical Lie algebras for translation-invariant 2-local spin systems in one dimension
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Wiersema, Roeland, Kökcü, Efekan, Kemper, Alexander F., and Bakalov, Bojko N.
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Quantum Physics - Abstract
Much is understood about 1-dimensional spin chains in terms of entanglement properties, physical phases, and integrability. However, the Lie algebraic properties of the Hamiltonians describing these systems remain largely unexplored. In this work, we provide a classification of all Lie algebras generated by translation-invariant 2-local spin chain Hamiltonians, or so-called dynamical Lie algebras. We consider chains with open and periodic boundary conditions and find 17 unique dynamical Lie algebras. Our classification covers some well-known models such as the transverse-field Ising model and the Heisenberg chain, and we also find more exotic classes of Hamiltonians that cannot be identified easily. In addition to the closed and open spin chains, we consider systems with a fully connected topology, which may be relevant for quantum machine learning approaches. We discuss the practical implications of our work in the context of quantum control, variational quantum computing, and the spin chain literature.
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- 2023
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19. Poisson Pseudoalgebras
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Bakalov, Bojko and Wang, Ju
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Mathematics - Quantum Algebra ,Primary 17B63, Secondary 17B65, 17B66, 18M70 - Abstract
For any cocommutative Hopf algebra $H$ and a left $H$-module $V$, we construct an operad $\mathcal{P}^{cl}_H(V)$, which in the special case when $H$ is the algebra of polynomials in one variable reduces to the classical operad $\mathcal{P}^{cl}(V)$. Morphisms from the Lie operad to $\mathcal{P}^{cl}(V)$ correspond to Poisson vertex algebra structures on $V$. Likewise, our operad $\mathcal{P}^{cl}_H(V)$ gives rise to the notion of a Poisson pseudoalgebra; thus extending the notion of a Lie pseudoalgebra. As a byproduct of our construction, we introduce two cohomology theories for Poisson pseudoalgebras, generalizing the variational and classical cohomology of Poisson vertex algebras., Comment: 47 pages
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- 2023
20. Virasoro constraints for moduli of sheaves and vertex algebras
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Bojko, Arkadij, Lim, Woonam, and Moreira, Miguel
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- 2024
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21. Emerging technologies: analytical lab vs. clinical lab perspective. Common goals and gaps to be filled in the pursuit of green and sustainable solutions
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Bojko, Barbara
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- 2024
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22. A Lie algebraic theory of barren plateaus for deep parameterized quantum circuits
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Michael Ragone, Bojko N. Bakalov, Frédéric Sauvage, Alexander F. Kemper, Carlos Ortiz Marrero, Martín Larocca, and M. Cerezo
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Science - Abstract
Abstract Variational quantum computing schemes train a loss function by sending an initial state through a parametrized quantum circuit, and measuring the expectation value of some operator. Despite their promise, the trainability of these algorithms is hindered by barren plateaus (BPs) induced by the expressiveness of the circuit, the entanglement of the input data, the locality of the observable, or the presence of noise. Up to this point, these sources of BPs have been regarded as independent. In this work, we present a general Lie algebraic theory that provides an exact expression for the variance of the loss function of sufficiently deep parametrized quantum circuits, even in the presence of certain noise models. Our results allow us to understand under one framework all aforementioned sources of BPs. This theoretical leap resolves a standing conjecture about a connection between loss concentration and the dimension of the Lie algebra of the circuit’s generators.
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- 2024
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23. Equivariant Segre and Verlinde invariants for Quot schemes
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Bojko, Arkadij and Huang, Jiahui
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Mathematics - Algebraic Geometry - Abstract
The problem of studying the two seemingly unrelated sets of invariants forming the Segre and the Verlinde series has gone through multiple different adaptations including a version for the virtual geometries of Quot schemes on surfaces and Calabi-Yau fourfolds. Our work is the first one to address the equivariant setting for both $\mathbb{C}^2$ and $\mathbb{C}^4$ by examining higher degree contributions which have no compact analogue. (1) For $\mathbb{C}^2$, we work mostly with virtual geometries of Quot schemes. After connecting the equivariant series in degree zero to the existing results of the first author for compact surfaces, we extend the Segre-Verlinde correspondence to all degrees and to the reduced virtual classes. Apart from it, we conjecture an equivariant symmetry between two different Segre series building again on previous work. (2) For $\mathbb{C}^4$, we give further motivation for the definition of the Verlinde series. Based on empirical data and additional structural results, we conjecture the equivariant Segre-Verlinde correspondence and the Segre-Segre symmetry analogous to the one for $\mathbb{C}^2$.
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- 2023
24. Finding the Optimal Time to Esophagectomy After Systemic Therapy Would be Finding a Lost Princess or Prince
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Bojko, Markian M. and Kim, Anthony W.
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- 2024
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25. Logarithmic vertex algebras and non-local Poisson vertex algebras
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Bakalov, Bojko and Villarreal, Juan
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Mathematics - Quantum Algebra ,Mathematical Physics ,17B69 (Primary), 17B63, 81R10, 81T40 (Secondary) - Abstract
Logarithmic vertex algebras were introduced in our previous paper, motivated by logarithmic conformal field theory. Non-local Poisson vertex algebras were introduced by De Sole and Kac, motivated by the theory of integrable systems. We prove that the associated graded vector space of any filtered logarithmic vertex algebra has an induced structure of a non-local Poisson vertex algebra. We use this relation to obtain new examples of both logarithmic vertex algebras and non-local Poisson vertex algebras. Dedicated to Victor G. Kac on his 80th birthday., Comment: 44 pages; v2 fixed minor typos
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- 2022
26. Orbifolds of Lattice Vertex Algebras
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Bakalov, Bojko, Elsinger, Jason, Kac, Victor G., and Todorov, Ivan
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Mathematics - Quantum Algebra ,High Energy Physics - Theory ,Mathematical Physics ,Primary 17B69, Secondary 81R10 - Abstract
To a positive-definite even lattice $Q$, one can associate the lattice vertex algebra $V_Q$, and any automorphism $\sigma$ of $Q$ lifts to an automorphism of $V_Q$. In this paper, we investigate the orbifold vertex algebra $V_Q^\sigma$, which consists of the elements of $V_Q$ fixed under $\sigma$, in the case when $\sigma$ has prime order. We describe explicitly the irreducible $V_Q^\sigma$-modules, compute their characters, and determine the modular transformations of characters. As an application, we find the asymptotic and quantum dimensions of all irreducible $V_Q^\sigma$-modules. We consider in detail the cases when the order of $\sigma$ is $2$ or $3$, as well as the case of permutation orbifolds., Comment: 105 pages
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- 2022
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27. Self-Improving SLAM in Dynamic Environments: Learning When to Mask
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Bojko, Adrian, Dupont, Romain, Tamaazousti, Mohamed, and Borgne, Hervé Le
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Computer Science - Computer Vision and Pattern Recognition ,Computer Science - Artificial Intelligence - Abstract
Visual SLAM - Simultaneous Localization and Mapping - in dynamic environments typically relies on identifying and masking image features on moving objects to prevent them from negatively affecting performance. Current approaches are suboptimal: they either fail to mask objects when needed or, on the contrary, mask objects needlessly. Thus, we propose a novel SLAM that learns when masking objects improves its performance in dynamic scenarios. Given a method to segment objects and a SLAM, we give the latter the ability of Temporal Masking, i.e., to infer when certain classes of objects should be masked to maximize any given SLAM metric. We do not make any priors on motion: our method learns to mask moving objects by itself. To prevent high annotations costs, we created an automatic annotation method for self-supervised training. We constructed a new dataset, named ConsInv, which includes challenging real-world dynamic sequences respectively indoors and outdoors. Our method reaches the state of the art on the TUM RGB-D dataset and outperforms it on KITTI and ConsInv datasets., Comment: Accepted to BMVC 2022. Dataset link: https://github.com/adrianbojko/consinv-dataset
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- 2022
28. Virasoro constraints on moduli of sheaves and vertex algebras
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Bojko, Arkadij, Lim, Woonam, and Moreira, Miguel
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Mathematics - Algebraic Geometry ,Mathematical Physics ,Mathematics - Combinatorics ,Mathematics - K-Theory and Homology ,Mathematics - Representation Theory - Abstract
In enumerative geometry, Virasoro constraints were first conjectured in Gromov-Witten theory with many new recent developments in the sheaf theoretic context. In this paper, we rephrase the sheaf-theoretic Virasoro constraints in terms of primary states coming from a natural conformal vector in Joyce's vertex algebra. This shows that Virasoro constraints are preserved under wall-crossing. As an application, we prove the conjectural Virasoro constraints for moduli spaces of torsion-free sheaves on any curve and on surfaces with only $(p,p)$ cohomology classes by reducing the statements to the rank 1 case.
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- 2022
29. Fatty liver index (FLI): more than a marker of hepatic steatosis
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Kaneva, Anastasiya M. and Bojko, Evgeny R.
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- 2024
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30. Hirsutonosema embarrassi n. gen. n. sp. (Phylum Microsporidia) in the Ovary of Mucket (Actinonaias ligamentina), Plain Pocketbook (Lampsilis cardium), and Fatmucket (Lampsilis siliquoidea) (Unionidae) from the Embarrass River, Wisconsin, USA
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Susan Knowles, Eric M. Leis, Jordan C. Richard, Isaac F. Standish, Jamie Bojko, Jesse Weinzinger, and Diane L. Waller
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Actinonaias ligamentina ,freshwater mussel ,Hirsutonosema embarrassi n. gen. n. sp. ,histopathology ,Lampsilis cardium ,Lampsilis siliquoidea ,Infectious and parasitic diseases ,RC109-216 ,Biology (General) ,QH301-705.5 - Abstract
During an epidemiological survey following a mortality event of freshwater mussels in 2018 in the Embarrass River, Wisconsin, USA, we identified a novel microsporidian parasite in the ovaries of mucket (Actinonaias ligamentina), plain pocketbook (Lampsilis cardium), and fatmucket (Lampsilis siliquoidea) (Unionidae). Histopathology showed round-to-oval microsporidian spores in the cytoplasm of oocytes in 60% (3/5) of female mucket, 100% (4/4) of female plain pocketbook, and 50% (1/2) of female fatmucket. Using transmission electron microscopy, we found that mature spores were round-to-oval and measured 4.13 ± 0.64 µm (3.14–5.31) long by 2.88 ± 0.37 µm (2.36–3.68) wide. The spores had a thin electron-dense exospore with a spiky “hairy” coat, a thick electron lucent endospore, diplokaryotic nuclei, a polar vacuole, and 27–28 polar filaments arranged in 1–3 rows. Sequencing of the small subunit rRNA produced a 1356 bp sequence most similar to that of Pseudonosema cristatellae (92%), and phylogenetic analysis grouped it within the freshwater Neopereziida. Genetic, morphological, and ultrastructural characteristics did not closely match those of other Pseudonosema spp., and a new genus and species, Hirsutonosema embarrassi n. gen. n. sp., were designated. Additional studies could evaluate host susceptibility, distribution, seasonality, transmission, and lethal or sub-lethal effects of this parasite on freshwater mussels.
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- 2024
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31. Surgical pulmonary arterioplasty at bidirectional cavopulmonary anastomosis leads to favorable pulmonary hemodynamics at final stage palliationCentral MessagePerspective
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Anna Olds, MD, W. Hampton Gray, MD, Markian Bojko, MD, Carly Weaver, BA, John D. Cleveland, MD, Michael E. Bowdish, MD, MS, Winfield J. Wells, MD, Vaughn A. Starnes, MD, and S. Ram Kumar, MD, PhD, FACS
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single ventricle ,Fontan ,bidirectional cavopulmonary anastomosis ,pulmonary arterioplasty ,Diseases of the circulatory (Cardiovascular) system ,RC666-701 ,Surgery ,RD1-811 - Abstract
Objective: Pulmonary arterioplasty (PA plasty) at bidirectional cavopulmonary anastomosis (BDCA) is associated with increased morbidity, but outcomes to final stage palliation are unknown. We sought to determine the influence of PA plasty on pulmonary artery growth and hemodyamics at Fontan. Methods: We retrospectively reviewed clinical data and outcomes for BDCA patients from 2006 to 2018. PA plasty was categorized by extent (type 1-4), as previously described. Outcomes included pulmonary artery reintervention and mortality before final palliation. Results: Five hundred eighty-eight patients underwent BDCA. One hundred seventy-nine patients (30.0%) underwent concomitant PA plasty. Five hundred seventy (97%) patients (169 [94%] PA plasty) survived to BDCA discharge. One hundred forty out of 570 survivors (25%) required PA/Glenn reintervention before final stage palliation (59 out of 169 [35%]) PA plasty; 81 out of 401 (20%) non-PA plasty; P
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- 2024
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32. Reconstruction of vertex algebras in even higher dimensions
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Bakalov, Bojko N. and Nikolov, Nikolay M.
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Mathematical Physics ,High Energy Physics - Theory ,Mathematics - Quantum Algebra ,17B69 (Primary), 81R10, 81T40 (Secondary) - Abstract
Vertex algebras in higher dimensions correspond to models of quantum field theory with global conformal invariance. Any vertex algebra in dimension D admits a restriction to a vertex algebra in any lower dimension and, in particular, to dimension one. In the case when D is even, we find natural conditions under which the converse passage is possible. These conditions include a unitary action of the conformal Lie algebra with a positive energy, which is given by local endomorphisms and obeys certain integrability properties., Comment: 27 pages; v5 changed the title, fixed typos and improved the exposition
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- 2022
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33. Perspective on in vivo SPME for human applications: Starting from monitoring doxorubicin during lung chemo-perfusion
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Wei Zhou, Runshan Will Jiang, Barbara Bojko, and Janusz Pawliszyn
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Therapeutics. Pharmacology ,RM1-950 - Published
- 2024
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34. Taking snapshots from a stream
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Bojko, Dominik and Cichoń, Jacek
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Computer Science - Information Retrieval ,Mathematics - Probability - Abstract
This work is devoted to a certain class of probabilistic snapshots for elements of the observed data stream. We show you how one can control their probabilistic properties and we show some potential applications. Our solution can be used to store information from the observed history with limited memory. It can be used for both web server applications and Ad hoc networks and, for example, for automatic taking snapshots from video stream online of unknown size.
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- 2022
35. Essential Fatty Acid Associated with Heart Rate Variability in Highly Trained Male Cross-Country Skiers: A Pilot Study
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Aleksandra Y. Lyudinina, Alexander L. Markov, and Evgeny R. Bojko
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autonomic nervous system ,heart rate variability ,alpha-linolenic acid ,arachidonic acid ,essential fatty acids ,cross-country skiers ,Physiology ,QP1-981 - Abstract
Polyunsaturated fatty acid (PUFA) metabolites play important roles in the modulation of vascular tone, heart rate variability (HRV), and cardiovascular diseases. This study was undertaken to examine the relationship between HRV and the plasma levels of essential acids. Methods: Highly trained cross-country skiers participated in the study (n = 19). Time-domain and frequency-domain HRV analyses were performed. The plasma levels of fatty acids were determined using gas–liquid chromatography. Results: Plasma eicosapentaenoic acid and docosahexaenoic acid were found to be negatively correlated with resting heart rate (HR) (p = 0.026). The plasma levels of alpha-linolenic acid (ALA) were positively associated with the relative value of high-frequency power (rs = 0.465, p = 0.045) and negatively correlated with the sympathovagal balance ratio (rs = −0.493, p = 0.032) and the absolute and relative values of low-frequency power (rs = −0.490, p = 0.028). The plasma levels of arachidonic acid (ARA) were positively associated with the relative value of high-frequency power (rs = 0.59, p = 0.006) and negatively correlated with the sympathovagal balance ratio (rs = −0.54, p = 0.017) and the relative values of low-frequency power (rs = −0.52, p = 0.022). No correlation was found between n6/n3 and HRV parameters except for HR and pNN50. Conclusions: n-3 PUFAs and ARA play an important role in the autonomic regulation of heart rate in highly trained skiers. Athletes with substantial deficiencies in plasma ALA and excess levels of ARA had increased sympathetic and decreased parasympathetic activity.
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- 2024
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36. Doxycycline reduces liver and kidney injuries in a rat hemorrhagic shock model
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Regina Sordi, Luana Bojko, Filipe R. M. B. Oliveira, Thiele Osvaldt Rosales, Camila Fernandes Souza, Lucas Wenceslau Moreno, Gustavo Ferreira Alves, José Carlos Rebuglio Vellosa, Daniel Fernandes, and Jose Rosa Gomes
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Hypovolemic shock ,Hemorrhage ,Nitric oxide ,Creatinine ,Drug repurposing ,Organ failure ,Medical emergencies. Critical care. Intensive care. First aid ,RC86-88.9 - Abstract
Abstract Background Hemorrhagic shock (HS), which causes insufficient tissue perfusion, can result in multiple organ failure (MOF) and death. This study aimed to evaluate whether doxycycline (DOX) protects cardiovascular, kidney, and liver tissue from damage in a rat model of HS. Immediately before the resuscitation, DOX (10 mg/kg; i.v.) was administered, and its protective effects were assessed 24 h later. Mean arterial pressure, renal blood flow, heart rate, vasoactive drug response, and blood markers such as urea, creatinine, AST, ALT, CPK, CPR, and NOx levels were determined. Results We showed that DOX has a significant effect on renal blood flow and on urea, creatinine, AST, ALT, CPK, and NOx. Morphologically, DOX reduced the inflammatory process in the liver tissue. Conclusions We conclude that DOX protects the liver and kidney against injury and dysfunction in a HS model and could be a strategy to reduce organ damage associated with ischemia-and-reperfusion injury.
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- 2024
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37. Logarithmic Vertex Algebras and Non-local Poisson Vertex Algebras
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Bakalov, Bojko and Villarreal, Juan J.
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- 2023
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38. Comparative Analysis of Chatbots Using Large Language Models for Web Development Tasks
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Pavel Smutny and Michal Bojko
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conversational AI ,web development automation ,code generation accuracy ,AI assistants ,performance evaluation ,Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Biology (General) ,QH301-705.5 ,Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
In this study, we compare the performance of five chatbots using large language models (LLMs) in handling web development tasks. Three human testers asked each chatbot nine predefined questions related to creating a simple website with a dynamic form and database integration. The questions covered tasks such as generating a web document structure, designing a layout, creating a form, and implementing database queries. The chatbots’ outputs were ranked based on accuracy, completeness, creativity, and security. The experiment reveals that conversational chatbots are adept at managing complex tasks, while programming assistants require more precisely formulated tasks or the ability to generate new responses to address irrelevant outputs. The findings suggest that conversational chatbots are more capable of handling a broader range of web development tasks with minimal supervision, whereas programming assistants need more precise task definitions to achieve comparable results. This study contributes to understanding the strengths and limitations of various LLM-based chatbots in practical coding scenarios, offering insights for their application in web development.
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- 2024
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39. Induction and Characteristics of Callus Cultures of the Medicinal Plant Tussilago farfara L.
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Monika Bojko, Magdalena Kędra, Agata Adamska, Zuzanna Jakubowska, Monika Tuleja, and Beata Myśliwa-Kurdziel
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carotenoids ,chlorophyll ,coltsfoot ,fluorescence ,histology ,organogenesis ,Botany ,QK1-989 - Abstract
Tussilago farfara L. is a traditional medicinal plant valued for its potentially health-promoting metabolites. Its herbal raw material has been recognized and used since ancient times and continues to be widely used in traditional medicine. Introducing this plant species to in vitro cultivation is a challenging task, but once the protocol is developed, such cultures can provide an abundant and inexhaustible source of plant material. In this study, we report the successful induction and growth of vigorous T. farfara callus in vitro. Callus induction was achieved on MS solid media with the combination of indole-3-acetic acid (3 mg/L) and benzyl aminopurine (2 mg/L) in darkness, whereas it appeared inefficient under light conditions and in suspension culture. We present a detailed description of callus growth kinetics, morphological analysis, photosynthetic activity, and biochemical parameters (including protein content and photosynthetic pigments) supported by histological studies. Furthermore, we observed the potential for organogenesis and somatic embryogenesis. This method for the in vitro propagation of T. farfara, along with callus culture maintenance, offers a wide range of applications in pharmacy for the production of valuable metabolites. Moreover, it could benefit the environment by reducing the depletion of natural populations of this species and may serve as an alternative strategy for species conservation in light of global warming.
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- 2024
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40. Synthesis of Carborane–Thiazole Conjugates as Tyrosinase and 11β-Hydroxysteroid Dehydrogenase Inhibitors: Antiproliferative Activity and Molecular Docking Studies
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Beata Donarska, Joanna Cytarska, Dominika Kołodziej-Sobczak, Renata Studzińska, Daria Kupczyk, Angelika Baranowska-Łączkowska, Karol Jaroch, Paulina Szeliska, Barbara Bojko, Daria Różycka, Agnieszka B. Olejniczak, Wojciech Płaziński, and Krzysztof Z. Łączkowski
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carborane ,thiazole ,tyrosinase ,antiproliferative activity ,11β-hydroxysteroid dehydrogenase ,molecular docking ,Organic chemistry ,QD241-441 - Abstract
The presented study depicts the synthesis of 11 carborane–thiazole conjugates with anticancer activity, as well as an evaluation of their biological activity as inhibitors of two enzymes: tyrosinase and 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1). The overexpression of tyrosinase results in the intracellular accumulation of melanin and can be observed in melanoma. The overexpression of 11β-HSD1 results in an elevation of glucocorticoid levels and has been associated with the aggravation of metabolic disorders such as type II diabetes mellitus and obesity. Recently, as the comorbidity of melanomas and metabolic disorders is being recognized as an important issue, the search for new therapeutic options has intensified. This study demonstrates that carborane–thiazole derivatives inhibit both enzymes, exerting beneficial effects. The antiproliferative action of all newly synthesized compounds was evaluated using three cancer cell lines, namely A172 (human brain glioblastoma), B16F10 (murine melanoma) and MDA-MB-231 (human breast adenocarcinoma), as well as a healthy control cell line of HUVEC (human umbilical vein endothelial cells). The results show that 9 out of 11 newly synthesized compounds demonstrated similar antiproliferative action against the B16F10 cell line to the reference drug, and three of these compounds surpassed it. To the best of our knowledge, this study is the first to demonstrate dual inhibitory action of carborane–thiazole derivatives against both tyrosinase and 11β-HSD1. Therefore, it represents the first step towards the simultaneous treatment of melanoma and comorbid diseases such as type II diabetes mellitus.
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- 2024
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41. Mentoring Models in Research in Polish Academia
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Bojko, Marta and Kowalczyk, Barbara
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In the highly competitive research sector, performance pressure is leading to the stratification of the academic profession, and to difficulties for early-career researchers. Support is therefore vital for talent retention, and to avoid 'brain drain'. However, limited research has distinguished varying models of professional support in research careers. After differentiating mentoring from co-worker support, and early-career scholars from senior researchers, this study performed statistical analysis on data collected from a representative survey of 840 scientists in Poland. Its intention was to discover the prevailing models of professional support in research in Polish academia, and to identify their relationship with job satisfaction and scientific development, teamwork, and stability of employment. The findings revealed that mentees in traditional hierarchical relationships received comprehensive support, while those who received assistance from their co-workers reported less perceptible benefits. Moreover, gender was found to be an important aspect of professional support relationships, with most scientists being supported by mentors of the same gender as themselves. Finally, differences were observed between the work environment assessments of the recipients of different support models. This paper discusses the theoretical and practical implications for academics, academic developers, and institutions which face wide disparities in supporting academic development, and are affected by turnover of early-career staff.
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- 2023
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42. Tree exploration in dual-memory model
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Bojko, Dominik, Gotfryd, Karol, Kowalski, Dariusz R., and Pajak, Dominik
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Computer Science - Distributed, Parallel, and Cluster Computing - Abstract
We study the problem of online tree exploration by a deterministic mobile agent. Our main objective is to establish what features of the model of the mobile agent and the environment allow linear exploration time. We study agents that, upon entering to a node, do not receive as input the edge via which they entered. In such a model, deterministic memoryless exploration is infeasible, hence the agent needs to be allowed to use some memory. The memory can be located at the agent or at each node. The existing lower bounds show that if the memory is either only at the agent or only at the nodes, then the exploration needs superlinear time. We show that tree exploration in dual-memory model, with constant memory at the agent and logarithmic at each node is possible in linear time when one of two additional features is present: fixed initial state of the memory at each node (so called clean memory) or a single movable token. We present two algorithms working in linear time for arbitrary trees in these two models. On the other hand, in our lower bound we show that if the agent has a single bit of memory and one bit is present at each node, then exploration may require quadratic time on paths, if the initial memory at nodes could be set arbitrarily (so called dirty memory). This shows that having clean node memory or a token allows linear exploration of trees in the model with two types of memory, but having neither of those features may lead to quadratic exploration time even on a simple path.
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- 2021
43. Wall-crossing for punctual Quot-schemes
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Bojko, Arkadij
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Mathematics - Algebraic Geometry ,Mathematics - Combinatorics - Abstract
We study punctual quot-schemes of torsion-free sheaves $E_Y$ on smooth projective curves, surfaces and Calabi--Yau fourfolds via their virtual geometry. Our goal is to give a complete description of the virtual fundamental classes and their tautological integrals. In the fourfold case, we first construct these classes under additional conditions. We use novel methods relying on the wall-crossing of Joyce. Our results include -the dependence of the cobordism classes on the torsion-free sheaf $E_Y$ where $Y$ is a surface, -relations to the previous results in the literature, which addressed the case of a trivial $E_Y$, -a new 12-fold correspondence relating Segre and Verlinde invariants for curves, surfaces and Calabi-Yau fourfolds based on the one observed by Arbesfeld-Johnson-Lim-Oprea-Pandharipande in dimensions one and two, -a closed formula for the Nekrasov genus, which gives a compact analogue of Nekrasov's conjecture. As our techniques are orthogonal to the original literature, we make our work independent by proving a new combinatorial identity in arXiv:2111.09868
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- 2021
44. Application of Lagrange inversion to wall-crossing for Quot schemes on surfaces
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Bojko, Arkadij
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Mathematics - Combinatorics ,Mathematics - Algebraic Geometry - Abstract
Motivated by my work on enumerative invariants for Quot schemes, I related two power series obtained by two different means. One of them was computed using geometric arguments via virtual localization methods and the other one came from working with representation theoretic objects called vertex algebras. In this note, I give proof of the equality of the two power series by relying only on techniques related to Lagrange inversion. This makes my work on Quot schemes independent of the previous results in the literature and proves a new combinatorial identity.
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- 2021
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45. The impact of normothermic and hypothermic preservation methods on kidney lipidome—comparative study using chemical biopsy with microextraction probes
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Natalia Warmuzińska, Kamil Łuczykowski, Iga Stryjak, Hernando Rosales-Solano, Peter Urbanellis, Janusz Pawliszyn, Markus Selzner, and Barbara Bojko
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solid-phase microextraction ,SPME ,LC-MS ,kidney transplantation ,lipidomics ,graft quality assessment ,Biology (General) ,QH301-705.5 - Abstract
IntroductionNormothermic ex vivo kidney perfusion (NEVKP) is designed to replicate physiological conditions to improve graft outcomes. A comparison of the impact of hypothermic and normothermic preservation techniques on graft quality was performed by lipidomic profiling using solid-phase microextraction (SPME) chemical biopsy as a minimally invasive sampling approach.MethodsDirect kidney sampling was conducted using SPME probes coated with a mixed-mode extraction phase in a porcine autotransplantation model of the renal donor after cardiac death, comparing three preservation methods: static cold storage (SCS), NEVKP, and hypothermic machine perfusion (HMP). The lipidomic analysis was done using ultra-high-performance liquid chromatography coupled with a Q-Exactive Focus Orbitrap mass spectrometer.ResultsChemometric analysis showed that the NEVLP group was separated from SCS and HMP groups. Further in-depth analyses indicated significantly (p < 0.05, VIP > 1) higher levels of acylcarnitines, phosphocholines, ether-linked and longer-chain phosphoethanolamines, triacylglycerols and most lysophosphocholines and lysophosphoethanolamines in the hypothermic preservation group. The results showed that the preservation temperature has a more significant impact on the lipidomic profile of the kidney than the preservation method’s mechanical characteristics.ConclusionHigher levels of lipids detected in the hypothermic preservation group may be related to ischemia-reperfusion injury, mitochondrial dysfunction, pro-inflammatory effect, and oxidative stress. Obtained results suggest the NEVKP method’s beneficial effect on graft function and confirm that SPME chemical biopsy enables low-invasive and repeated sampling of the same tissue, allowing tracking alterations in the graft throughout the entire transplantation procedure.
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- 2024
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46. Peptide-based inhibitors targeting the PD-1/PD-L1 axis: potential immunotherapeutics for cancer
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Magdalena Bojko, Katarzyna Węgrzyn, Emilia Sikorska, Piotr Ciura, Claire Battin, Peter Steinberger, Katarzyna Magiera-Mularz, Grzegorz Dubin, Adam Kulesza, Adam K. Sieradzan, Marta Spodzieja, and Sylwia Rodziewicz-Motowidło
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PD-1 - Programmed cell death 1 ,PD-L1 - Programmed cell death 1 - ligand 1 ,Immune checkpoint inhibitor ,Disulfide-linked peptide ,Immunotherapy ,Cancer ,Neoplasms. Tumors. Oncology. Including cancer and carcinogens ,RC254-282 - Abstract
The PD-1/PD-L1 complex belongs to the group of inhibitory immune checkpoints and plays a critical role in immune regulation. The PD-1/PD-L1 axis is also responsible for immune evasion of cancer cells, and this complex is one of the main targets of immunotherapies used in oncology. Treatment using immune checkpoint inhibitors is mainly based on antibodies. This approach has great therapeutic potential; however, it also has major drawbacks and can induce immune-related adverse events. Thus, there is a strong need for alternative, non-antibody-based therapies using small molecules, peptides, or peptidomimetics. In the present study, we designed, synthesized, and evaluated a set of PD-1-targeting peptides based on the sequence and structure of PD-L1. The binding of these peptides to PD-1 was investigated using SPR and ELISA. We also assessed their ability to compete with PD-L1 for binding to PD-1 and their inhibitory properties against the PD-1/PD-L1 complex at the cellular level. The best results were obtained for the peptide PD-L1(111–127)(Y112C-I126C), named (L11), which displaced PD-L1 from binding to PD-1 in the competitive assay and inhibited the formation of the PD-1/PD-L1 complex. The (L11) peptide also exhibited strong affinity for PD-1. NMR studies revealed that (L11) does not form a well-defined secondary structure; however, MD simulation indicated that (L11) binds to PD-1 at the same place as PD-L1. After further optimization of the structure, the peptide inhibitor obtained in this study could also be used as a potential therapeutic compound targeting the PD-1/PD-L1 axis.
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- 2024
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47. Logarithmic Vertex Algebras
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Bakalov, Bojko and Villarreal, Juan J.
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Mathematics - Quantum Algebra ,Mathematical Physics ,Primary 17B69, Secondary 81R10, 81T40 - Abstract
We introduce and study the notion of a logarithmic vertex algebra, which is a vertex algebra with logarithmic singularities in the operator product expansion of quantum fields; thus providing a rigorous formulation of the algebraic properties of quantum fields in logarithmic conformal field theory. We develop a framework that allows many results about vertex algebras to be extended to logarithmic vertex algebras, including in particular the Borcherds identity and Kac Existence Theorem. Several examples are investigated in detail, and they exhibit some unexpected new features that are peculiar to the logarithmic case., Comment: 62 pages
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- 2021
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48. In vivo solid phase microextraction for therapeutic monitoring and pharmacometabolomic fingerprinting of lung during in vivo lung perfusion of FOLFOX
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Nikita Looby, Anna Roszkowska, Miao Yu, German Rios-Gomez, Mauricio Pipkin, Barbara Bojko, Marcelo Cypel, and Janusz Pawliszyn
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In vivo lung perfusion ,Solid-phase microextraction ,Chemotherapy ,Metabolomics ,Therapeutic drug monitoring ,Therapeutics. Pharmacology ,RM1-950 - Abstract
In vivo lung perfusion (IVLP) is a novel isolated lung technique developed to enable the local, in situ administration of high-dose chemotherapy to treat metastatic lung cancer. Combination therapy using folinic acid (FOL), 5-fluorouracil (F), and oxaliplatin (OX) (FOLFOX) is routinely employed to treat several types of solid tumours in various tissues. However, F is characterized by large interpatient variability with respect to plasma concentration, which necessitates close monitoring during treatments using of this compound. Since plasma drug concentrations often do not reflect tissue drug concentrations, it is essential to utilize sample-preparation methods specifically suited to monitoring drug levels in target organs. In this work, in vivo solid-phase microextraction (in vivo SPME) is proposed as an effective tool for quantitative therapeutic drug monitoring of FOLFOX in porcine lungs during pre-clinical IVLP and intravenous (IV) trials. The concomitant extraction of other endogenous and exogenous small molecules from the lung and their detection via liquid chromatography coupled to high resolution mass spectrometry (LC-HRMS) enabled an assessment of FOLFOX's impact on the metabolomic profile of the lung and revealed the metabolic pathways associated with the route of administration (IVLP vs. IV) and the therapy itself. This study also shows that the immediate instrumental analysis of metabolomic samples is ideal, as long-term storage at −80 °C results in changes in the metabolite content in the sample extracts.
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- 2023
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49. Orbifolds of lattice vertex algebras
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Bakalov, Bojko, Elsinger, Jason, Kac, Victor G., and Todorov, Ivan
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- 2023
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50. Wall-crossing for zero-dimensional sheaves and Hilbert schemes of points on Calabi-Yau 4-folds
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Bojko, Arkadij
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Mathematics - Algebraic Geometry ,Mathematics - K-Theory and Homology ,Mathematics - Representation Theory - Abstract
Gross-Joyce-Tanaka arXiv:2005.05637 proposed a wall-crossing conjecture for Calabi-Yau fourfolds. Assuming it, we prove the conjecture of Cao-Kool arXiv:1712.07347 for 0-dimensional sheaf-counting invariants on projective Calabi-Yau 4-folds. From it, we extract the full topological information contained in the virtual fundamental classes of Hilbert schemes of points which turns out to be equivalent to the data of all descendent integrals. As a consequence, we can express many generating series of invariants in terms of explicit universal power series. i) On $\mathbb{C}^4$, Nekrasov proposed invariants with a conjectured closed form arXiv:1712.08128. We show that an analog of his formula holds for compact Calabi-Yau 4-folds satisfying the wall-crossing conjecture. ii) We notice a relationship to corresponding generating series for Quot schemes on elliptic surfaces which are also governed by a wall-crossing formula. This leads to a Segre-Verlinde correspondence for Calabi-Yau fourfolds.
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- 2021
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