cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Periodicity in the cohomology of symmetric groups via divided powers
Creators: name: Nagpal, Rohit
name: Snowden, Andrew
Publisher: name: arXiv
Year: 2017
Subjects: subject: Representation Theory (math.RT)
subject: Algebraic Topology (math.AT)
subject: FOS: Mathematics

description: A famous theorem of Nakaoka asserts that the cohomology of the symmetric group stabilizes. The first author generalized this theorem to non-trivial coefficient systems, in the form of $\mathrm{FI}$-modules over a field, though one now obtains periodicity of the cohomology instead of stability. In this paper, we further refine these results. Our main theorem states that if $M$ is a finitely generated $\mathrm{FI}$-module over a noetherian ring $\mathbf{k}$ then $\bigoplus_{n \ge 0} \mathrm{H}^t(S_n, M_n)$ admits the structure of a $\mathbf{D}$-module, where $\mathbf{D}$ is the divided power algebra over $\mathbf{k}$ in a single variable, and moreover, this $\mathbf{D}$-module is "nearly" finitely presented. This immediately recovers the periodicity result when $\mathbf{k}$ is a field, but also shows, for example, how the torsion varies with $n$ when $\mathbf{k}=\mathbf{Z}$. Using the theory of connections on $\mathbf{D}$-modules, we establish sharp bounds on the period in the case where $\mathbf{k}$ is a field. We apply our theory to obtain results on the modular cohomology of Specht modules and the integral cohomology of unordered configuration spaces of manifolds.
description: Fixed some minor mistakes and expanded the section on configuration spaces
The Abraham-Lorentz force and electrodynamics at the classical electron radius
Creators: name: Polonyi, Janos
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: The Abraham-Lorentz force is a finite remnant of the UV singular structure of the self interaction of a point charge with its own field. The satisfactory description of such interaction needs a relativistic regulator. This turns out to be a problematic point because the energy of regulated relativistic cutoff theories is unbounded from below. However one can construct point splitting regulators which keep the Abraham-Lorentz force stable. The classical language can be reconciled with QED by pointing out that the effective quantum theory for the electric charge supports a saddle point producing the classical radiation reaction forces.
description: final version, Int. J. Mod. Phys. 43 1950077 (2019)
Overall momentum balance and redistribution of the lost energy in asymmetric dijet events in 2.76~ATeV Pb-Pb collisions with a multi-phase transport model
Creators: name: Gao, Zhan
name: Luo, Ao
name: Ma, Guo-Liang
name: Qin, Guang-You
name: Zhang, Han-Zhong
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: The overall transverse momentum balance and the redistribution of the lost energy from hard jets for asymmetric dijet events in PbPb collisions at 2.76~ATeV at the LHC is studied within A Multi-Phase Transport (AMPT) model. A detailed analysis is performed for the projected transverse momentum $\langle \slashed{p}_{T}^{||} \rangle$ contributed from the final charged hadrons carrying different transverse momenta and emitted from different angular directions. We find that the transverse momentum projection $\langle \slashed{p}_{T}^{||} \rangle $ in the leading jet direction is mainly contributed by hard hadrons ($p_T > 8.0$~GeV/$c$) in both peripheral and central PbPb collisions, while the opposite direction in central collisions is dominated by soft hadrons ($p_T = 0.5$-$2.0$~GeV/$c$). The study of in-cone and out-of-cone contributions to $\langle \slashed{p}_{T}^{||} \rangle$ shows that these soft hadrons are mostly emitted at large angles away from the dijet axis. Our AMPT calculation is in qualitative agreement with the CMS measurements and the primary mechanism for the energy transported to large angles in the AMPT model is the elastic scattering at the partonic stage. Future studies including also inelastic processes should be helpful in understanding the overestimation of the magnitudes of in-cone and out-of-cone imbalances from our AMPT calculations, and shed light on different roles played by radiative and collisional processes in the redistribution of the lost energy from hard jets.
description: 11 pages, 7 figures
A review on multiple sclerosis prognostic findings from imaging, inflammation, and mental health studies
Creators: name: Brasanac, Jelena
name: Chien, Claudia
Publisher: name: Charité - Universitätsmedizin Berlin
Year: 2023
Subjects: subject: multiple sclerosis
subject: magnetic resonance imaging (MRI)
subject: mental health
subject: depression
subject: neuroinflammation
subject: 600 Technik, Medizin, angewandte Wissenschaften::610 Medizin und Gesundheit::610 Medizin und Gesundheit

description: Magnetic resonance imaging (MRI) of the brain is commonly used to detect where chronic and active lesions are in multiple sclerosis (MS). MRI is also extensively used as a tool to calculate and extrapolate brain health by way of volumetric analysis or advanced imaging techniques. In MS patients, psychiatric symptoms are common comorbidities, with depression being the main one. Even though these symptoms are a major determinant of quality of life in MS, they are often overlooked and undertreated. There has been evidence of bidirectional interactions between the course of MS and comorbid psychiatric symptoms. In order to mitigate disability progression in MS, treating psychiatric comorbidities should be investigated and optimized. New research for the prediction of disease states or phenotypes of disability have advanced, primarily due to new technologies and a better understanding of the aging brain.
The role of myeloid derived suppressor cells in musculoskeletal disorders
Creators: name: Ren, Yi
name: Bäcker, Henrik
name: Müller, Michael
name: Kienzle, Arne
Publisher: name: Charité - Universitätsmedizin Berlin
Year: 2023
Subjects: subject: myeloid derived suppressor cell (MDSC)
subject: bone metabolism
subject: osteoclast
subject: osteoblast
subject: immune cells
subject: inflammation
subject: osteoimmunology
subject: 600 Technik, Medizin, angewandte Wissenschaften::610 Medizin und Gesundheit::610 Medizin und Gesundheit

description: The immune system is closely linked to bone homeostasis and plays a pivotal role in several pathological and inflammatory conditions. Through various pathways it modulates various bone cells and subsequently sustains the physiological bone metabolism. Myeloid-derived suppressor cells (MDSCs) are a group of heterogeneous immature myeloid-derived cells that can exert an immunosuppressive function through a direct cell-to-cell contact, secretion of anti-inflammatory cytokines or specific exosomes. These cells mediate the innate immune response to chronic stress on the skeletal system. In chronic inflammation, MDSCs act as an inner offset to rebalance overactivation of the immune system. Moreover, they have been found to be involved in processes responsible for bone remodeling in different musculoskeletal disorders, autoimmune diseases, infection, and cancer. These cells can not only cause bone erosion by differentiating into osteoclasts, but also alleviate the immune reaction, subsequently leading to long-lastingly impacted bone remodeling. In this review, we discuss the impact of MDSCs on the bone metabolism under several pathological conditions, the involved modulatory pathways as well as potential therapeutic targets in MDSCs to improve bone health.
Primary ChAdOx1 vaccination does not reactivate pre-existing, cross-reactive immunity
Creators: name: Henze, Larissa
name: Braun, Julian
name: Meyer-Arndt, Lil
name: Jürchott, Karsten
name: Schlotz, Maike
name: Michel, Janine
name: Grossegesse, Marica
name: Mangold, Maike
name: Dingeldey, Manuela
name: Kruse, Beate
name: Holenya, Pavlo
name: Mages, Norbert
name: Reimer, Ulf
name: Eckey, Maren
name: Schnatbaum, Karsten
name: Wenschuh, Holger
name: Timmermann, Bernd
name: Klein, Florian
name: Nitsche, Andreas
name: Giesecke-Thiel, Claudia
name: Loyal, Lucie
name: Thiel, Andreas
Publisher: name: Charité - Universitätsmedizin Berlin
Year: 2023
Subjects: subject: SARS-CoV-2
subject: antigen-specific T-cells
subject: cross-reactivity
subject: heterologous vaccination
subject: humoral response
subject: 600 Technik, Medizin, angewandte Wissenschaften::610 Medizin und Gesundheit::610 Medizin und Gesundheit

description: Currently available COVID-19 vaccines include inactivated virus, live attenuated virus, mRNA-based, viral vectored and adjuvanted protein-subunit-based vaccines. All of them contain the spike glycoprotein as the main immunogen and result in reduced disease severity upon SARS-CoV-2 infection. While we and others have shown that mRNA-based vaccination reactivates pre-existing, cross-reactive immunity, the effect of vector vaccines in this regard is unknown. Here, we studied cellular and humoral responses in heterologous adenovirus-vector-based ChAdOx1 nCOV-19 (AZ; Vaxzeria, AstraZeneca) and mRNA-based BNT162b2 (BNT; Comirnaty, BioNTech/Pfizer) vaccination and compared it to a homologous BNT vaccination regimen. AZ primary vaccination did not lead to measurable reactivation of cross-reactive cellular and humoral immunity compared to BNT primary vaccination. Moreover, humoral immunity induced by primary vaccination with AZ displayed differences in linear spike peptide epitope coverage and a lack of anti-S2 IgG antibodies. Contrary to primary AZ vaccination, secondary vaccination with BNT reactivated pre-existing, cross-reactive immunity, comparable to homologous primary and secondary mRNA vaccination. While induced anti-S1 IgG antibody titers were higher after heterologous vaccination, induced CD4(+) T cell responses were highest in homologous vaccinated. However, the overall TCR repertoire breadth was comparable between heterologous AZ-BNT-vaccinated and homologous BNT-BNT-vaccinated individuals, matching TCR repertoire breadths after SARS-CoV-2 infection, too. The reasons why AZ and BNT primary vaccination elicits different immune response patterns to essentially the same antigen, and the associated benefits and risks, need further investigation to inform vaccine and vaccination schedule development.
Susceptible-infected-susceptible model on networks with eigenvector localization
Creators: name: Wei, Zong-Wen
name: Wang, Bing-Hong
Publisher: name: arXiv
Year: 2017
Subjects: subject: Physics and Society (physics.soc-ph)
subject: FOS: Physical sciences

description: It is a longstanding debate on the absence of threshold for susceptible-infected-susceptible (SIS) model on networks with finite second order moment of degree distribution. The eigenvector localization of the adjacency matrix for a network gives rise to the inactive Griffiths phase featuring slow decay of the activity localized around highly connected nodes due to the dynamical fluctuation. We show how it dramatically changes our understanding of SIS model, opening up new possibilities for the debate. We derive the critical condition for Griffiths to active phase transition: on average, an infected node can further infect another one in the characteristic lifespan of the star subgraph composed of the node and its nearest neighbors. The system approaches the critical point of avoiding the irreversible dynamical fluctuation and the trap of absorbing state. As a signature of the phase transition, the infection density of a node is not only proportional to its degree, but also proportional to the exponentially growing lifespan of the star. And the divergence of the average lifespan of the stars is responsible for the vanishing threshold in the thermodynamic limit. The eigenvector localization exponentially reinforces the infection of highly connected nodes, while it inversely suppresses the infection of small-degree nodes.
A GAMP Based Low Complexity Sparse Bayesian Learning Algorithm
Creators: name: Al-Shoukairi, Maher
name: Schniter, Philip
name: Rao, Bhaskar D.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Machine Learning (cs.LG)
subject: Machine Learning (stat.ML)
subject: FOS: Computer and information sciences

description: In this paper, we present an algorithm for the sparse signal recovery problem that incorporates damped Gaussian generalized approximate message passing (GGAMP) into Expectation-Maximization (EM)-based sparse Bayesian learning (SBL). In particular, GGAMP is used to implement the E-step in SBL in place of matrix inversion, leveraging the fact that GGAMP is guaranteed to converge with appropriate damping. The resulting GGAMP-SBL algorithm is much more robust to arbitrary measurement matrix $\boldsymbol{A}$ than the standard damped GAMP algorithm while being much lower complexity than the standard SBL algorithm. We then extend the approach from the single measurement vector (SMV) case to the temporally correlated multiple measurement vector (MMV) case, leading to the GGAMP-TSBL algorithm. We verify the robustness and computational advantages of the proposed algorithms through numerical experiments.
ILC2 require cell-intrinsic ST2 signals to promote type 2 immune responses
Creators: name: Topczewska, Patrycja M.
name: Rompe, Zoe A.
name: Jakob, Manuel O.
name: Stamm, Anton
name: Leclère, Pierre S.
name: Preußer, Alexandra
name: Duerr, Claudia U.
name: Thole, Linda Marie Laura
name: Kotsch, Katja
name: Artis, David
name: Klose, Christoph S. N.
Publisher: name: Charité - Universitätsmedizin Berlin
Year: 2023
Subjects: subject: ILC2 - group 2 innate lymphoid cell
subject: IL-33 and ST2
subject: type 2 immune response
subject: mucosal immunity
subject: innate immunity
subject: 600 Technik, Medizin, angewandte Wissenschaften::610 Medizin und Gesundheit::610 Medizin und Gesundheit

description: The initiation of type 2 immune responses at mucosal barriers is regulated by rapidly secreted cytokines called alarmins. The alarmins IL-33, IL-25 and TSLP are mainly secreted by stromal and epithelial cells in tissues and were linked to chronic inflammatory diseases, such as allergic lung inflammation, or to resistance against worm infections. Receptors for alarmins are expressed by a variety of immune cells, including group 2 innate lymphoid cells (ILC2s), an early source of the type 2 cytokines, such as IL-5 and IL-13, which have been linked to atopic diseases and anti-worm immunity as well. However, the precise contribution of the IL-33 receptor signals for ILC2 activation still needs to be completed due to limitations in targeting genes in ILC2. Using the newly established Nmur1(iCre-eGFP) mouse model, we obtained specific conditional genetic ablation of the IL-33 receptor subunit ST2 in ILC2s. ST2-deficient ILC2s were unresponsive to IL-33 but not to stimulation with the alarmin IL-25. As a result of defective ST2 signals, ILC2s produced limited amounts of IL-5 and IL-13 and failed to support eosinophil homeostasis. Further, ST2-deficient ILC2s were unable to expand and promote the recruitment of eosinophils during allergic lung inflammation provoked by papain administration. During infection with Nippostrongylus brasiliensis, ILC2-intrinsic ST2 signals were required to mount an effective type 2 immune response against the parasite leading to higher susceptibility against worm infection in conditional knockout mice. Therefore, this study argues for a non-redundant role of cell-intrinsic ST2 signals triggering proper activation of ILC2 for initiation of type 2 immunity.
The spatiotemporal doubled density operator: a unified framework for analyzing spatial and temporal quantum processes
Creators: name: Jia, Zhian
name: Kaszlikowski, Dagomir
Publisher: name: arXiv
Year: 2023
Subjects: subject: Quantum Physics (quant-ph)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: The measurement statistics for spatial and temporal quantum processes are produced through distinct mechanisms. Measurements that are space-like separated exhibit non-signaling behavior. However, time-like separated measurements can only result in one-way non-signaling, as the past is independent of the future, but the opposite is not true. This work presents the doubled density operator as a comprehensive framework for studying quantum processes in space-time. It effectively captures all the physical information of the process, with the measurement and Born rule showing uniformity for both spatial and temporal cases. We demonstrate that the equal-time density operator can be derived by performing a partial trace operation on the doubled density operator. Furthermore, the temporality of the quantum process can be detected by conducting a partial trace operation on either the left or right half of the doubled density operator.
description: v1:7+7 pages, comments welcome
Single-cell clonal tracking of persistent T-cells in allogeneic hematopoietic stem cell transplantation
Creators: name: Obermayer, Benedikt
name: Keilholz, Luisa
name: Conrad, Thomas
name: Frentsch, Marco
name: Blau, Igor-Wolfgang
name: Vuong, Lam
name: Lesch, Stella
name: Movasshagi, Kamran
name: Tietze-Stolley, Carola
name: Loyal, Lucie
name: Henze, Larissa
name: Penack, Olaf
name: Stervbo, Ulrik
name: Babel, Nina
name: Haas, Simon
name: Beule, Dieter
name: Bullinger, Lars
name: Wittenbecher, Friedrich
name: Na, Il-Kang
Publisher: name: Charité - Universitätsmedizin Berlin
Year: 2023
Subjects: subject: scRNAseq
subject: allogeneic HSCT
subject: leukemia
subject: transplantation
subject: T-cells
subject: clonal tracking
subject: 600 Technik, Medizin, angewandte Wissenschaften::610 Medizin und Gesundheit::610 Medizin und Gesundheit

description: The critical balance between intended and adverse effects in allogeneic hematopoietic stem cell transplantation (alloHSCT) depends on the fate of individual donor T-cells. To this end, we tracked alpha beta T-cell clonotypes during stem cell mobilization treatment with granulocyte-colony stimulating factor (G-CSF) in healthy donors and for six months during immune reconstitution after transfer to transplant recipients. More than 250 alpha beta T-cell clonotypes were tracked from donor to recipient. These clonotypes consisted almost exclusively of CD8(+) effector memory T cells (CD8TEM), which exhibited a different transcriptional signature with enhanced effector and cytotoxic functions compared to other CD8TEM. Importantly, these distinct and persisting clonotypes could already be delineated in the donor. We confirmed these phenotypes on the protein level and their potential for selection from the graft. Thus, we identified a transcriptional signature associated with persistence and expansion of donor T-cell clonotypes after alloHSCT that may be exploited for personalized graft manipulation strategies in future studies.
Memory and Rejuvenation in Glassy Systems
Creators: name: Freedberg, J.
name: Meese, W. Joe
name: He, J.
name: Schlagel, D. L.
name: Dahlberg, E. Dan
name: Orbach, R. L.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Soft Condensed Matter (cond-mat.soft)
subject: FOS: Physical sciences

description: The memory effect in a single crystal spin glass ($\mathrm{Cu}_{0.92}\mathrm{Mn}_{0.08}$) has been measured using \freq ac susceptibility techniques over a temperature range of $0.4 - 0.7 \, T_g$ and a model of the memory effect has been developed. A double-waiting-time protocol is carried out where the spin glass is first allowed to age at a temperature below $T_g$, followed by a second aging at a lower temperature, \Tw{2}, after it has fully rejuvenated. The model is based on calculating typical coincident growth of correlated regions at the two temperatures. It accounts for the absolute magnitude of the memory effect as a function of both waiting times and temperatures. The data can be explained by the memory loss being a function of the relative change in the correlated volume at the first waiting temperature because of the growth in the correlations at the second waiting temperature.
description: Published version: 13 pages, 6 figures
Improving Deep Representation Learning via Auxiliary Learnable Target Coding
Creators: name: Liu, Kangjun
name: Chen, Ke
name: Jia, Kui
name: Wang, Yaowei
Publisher: name: arXiv
Year: 2023
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: FOS: Computer and information sciences

description: Deep representation learning is a subfield of machine learning that focuses on learning meaningful and useful representations of data through deep neural networks. However, existing methods for semantic classification typically employ pre-defined target codes such as the one-hot and the Hadamard codes, which can either fail or be less flexible to model inter-class correlation. In light of this, this paper introduces a novel learnable target coding as an auxiliary regularization of deep representation learning, which can not only incorporate latent dependency across classes but also impose geometric properties of target codes into representation space. Specifically, a margin-based triplet loss and a correlation consistency loss on the proposed target codes are designed to encourage more discriminative representations owing to enlarging between-class margins in representation space and favoring equal semantic correlation of learnable target codes respectively. Experimental results on several popular visual classification and retrieval benchmarks can demonstrate the effectiveness of our method on improving representation learning, especially for imbalanced data. Source codes are made publicly available at \href{https://github.com/AkonLau/LTC}{https://github.com/AkonLau/LTC}.
description: Accepted by Pattern Recognition, 33 pages, 8 figures, 11 tables
Quasi Static Remanence in Dzyaloshinskii-Moriya Interaction driven Weak Ferromagnets and Piezomagnets
Creators: name: Pattnayak, Namrata
name: Bhattacharyya, Arpan
name: Nigam, A. K.
name: Cheong, Sang-Wook
name: Bajpai, Ashna
Publisher: name: arXiv
Year: 2017
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We explore remanent magnetization ($μ$) as a function of time and temperature, in a variety of rhombohedral antiferromagnets (AFM) which are also weak ferromagnets (WFM) and piezomagnets (PzM). These measurements, across samples with length scales ranging from nano to bulk, firmly establish the presence of a remanence that is quasi static in nature and exhibits a counter-intuitive magnetic field dependence. These observations unravel an ultra-slow magnetization relaxation phenomenon related to this quasi static remanence. This feature is also observed in a defect free single crystal of $α$-Fe$_2$O$_3$, which is a canonical WFM and PzM. Notably, $α$-Fe$_2$O$_3$ is not a typical geometrically frustrated AFM and in single crystal form, it is also devoid of any size or interface effects, which are the usual suspects for a slow magnetization relaxation phenomenon. The underlying pinning mechanism appears exclusive to those AFM which are either symmetry allowed WFM, driven by Dzyaloshinskii-Moriya Interaction (DMI) or can generate this trait by tuning of size and interface. The qualitative features of the quasi static remanence indicate that such WFM are potential piezomagnets, in which magnetization can be tuned by \textit{stress} alone.
Computational multi-spectral video imaging
Creators: name: Wang, Peng
name: Menon, Rajesh
Publisher: name: arXiv
Year: 2017
Subjects: subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: Multi-spectral imagers reveal information unperceivable to humans and conventional cameras. Here, we demonstrate a compact single-shot multi-spectral video-imaging camera by placing a micro-structured diffractive filter in close proximity to the image sensor. The diffractive filter converts spectral information to a spatial code on the sensor pixels. Following a calibration step, this code can be inverted via regularization-based linear algebra, to compute the multi-spectral image. We experimentally demonstrated spectral resolution of 9.6nm within the visible band (430nm to 718nm). We further show that the spatial resolution is enhanced by over 30% compared to the case without the diffractive filter. We also demonstrate Vis-IR imaging with the same sensor. Furthermore, our camera is able to computationally trade-off spectral resolution against the field of view in software without any change in hardware as long as sufficient sensor pixels are utilized for information encoding. Since no absorptive color filters are utilized, sensitivity is preserved as well. Finally, the diffractive filters can be easily manufactured using optical lithography and replication techniques.
Quantum violation of macrorealism under multi-outcome two-parameter generalised measurements
Creators: name: Das, Debarshi
name: Gayen, Arindam
name: Das, Ranit
name: Mal, Shiladitya
Publisher: name: arXiv
Year: 2017
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Generalised dichotomic quantum measurements are fully characterised by two real parameters, dubbed as sharpness parameter and biasedness parameter. The trade-off between the degree of joint measurability, sharpness and biasedness of generalised measurements was known in the case of pairs of qubit observables. In the present work we generalise the notion of sharpness and biasedness measure of multi-outcome generalised measurements pertaining to multilevel systems. A trade-off between the amount of quantum mechanical (QM) violation of macrorealism (MR), sharpness and biasedness is established. Specifically we found that the minimum value of sharpness parameter, above which the QM violations of different necessary conditions of MR persist, decreases with increase in biasedness. We also analysed the effect of biasedness parameter on the magnitudes of QM violations of different necessary conditions of MR for multilevel spin systems.
description: Close to published version
AutoSamp: Autoencoding k-space Sampling via Variational Information Maximization for 3D MRI
Creators: name: Alkan, Cagan
name: Mardani, Morteza
name: Liao, Congyu
name: Li, Zhitao
name: Vasanawala, Shreyas S.
name: Pauly, John M.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Image and Video Processing (eess.IV)
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: Accelerated MRI protocols routinely involve a predefined sampling pattern that undersamples the k-space. Finding an optimal pattern can enhance the reconstruction quality, however this optimization is a challenging task. To address this challenge, we introduce a novel deep learning framework, AutoSamp, based on variational information maximization that enables joint optimization of sampling pattern and reconstruction of MRI scans. We represent the encoder as a non-uniform Fast Fourier Transform that allows continuous optimization of k-space sample locations on a non-Cartesian plane, and the decoder as a deep reconstruction network. Experiments on public 3D acquired MRI datasets show improved reconstruction quality of the proposed AutoSamp method over the prevailing variable density and variable density Poisson disc sampling for both compressed sensing and deep learning reconstructions. We demonstrate that our data-driven sampling optimization method achieves 4.4dB, 2.0dB, 0.75dB, 0.7dB PSNR improvements over reconstruction with Poisson Disc masks for acceleration factors of R = 5, 10, 15, 25, respectively. Prospectively accelerated acquisitions with 3D FSE sequences using our optimized sampling patterns exhibit improved image quality and sharpness. Furthermore, we analyze the characteristics of the learned sampling patterns with respect to changes in acceleration factor, measurement noise, underlying anatomy, and coil sensitivities. We show that all these factors contribute to the optimization result by affecting the sampling density, k-space coverage and point spread functions of the learned sampling patterns.
description: Accepted for publication in IEEE Transactions on Medical Imaging (TMI)
The cosmic microwave background Cold Spot anomaly: the impact of sky masking and the expected contribution from the Integrated Sachs-Wolfe effect
Creators: name: Naidoo, Krishna
name: Benoit-Lévy, Aurélien
name: Lahav, Ofer
Publisher: name: arXiv
Year: 2017
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: We re-analyse the cosmic microwave background (CMB) Cold Spot (CS) anomaly with particular focus on understanding the bias a mask (contaminated by Galactic and point sources) may introduce. We measure the coldest spot, found by applying the Spherical Mexican Hat Wavelet transform on 100 000 cut-sky (masked) and full-sky CMB simulated maps. The CS itself is barely affected by the mask; we estimate a 94 per cent probability that the CS is the full-sky temperature minimum. However, approximately 48 per cent (masked fraction of the mask) of full-sky minima are obscured by the mask. Since the observed minima are slightly hotter than the full-sky ensemble of minima, a cut-sky analysis would have found the CS to be significant at approximately 2.2 sigma with a wavelet angular scale of R = 5 degrees. None the less, comparisons to full-sky minima show the CS significance to be only approximately 1.9 sigma and less than 2 sigma for all R. The CS on the last scattering surface may be hotter due to the integrated Sachs-Wolfe effect in the line of sight. However, our simulations show that this on average only approximately 10 per cent (about 10 micro K but consistent with zero) of the CS temperature profile. This is consistent with Lambda and cold dark matter reconstructions of this effect based on observed line-of-sight voids.
description: 6 pages, 5 figures, changes made to match version published in MNRAS
Distributors and the comprehensive factorization system for internal groupoids
Creators: name: Metere, Giuseppe
Publisher: name: arXiv
Year: 2017
Subjects: subject: Category Theory (math.CT)
subject: FOS: Mathematics
subject: 18A32, 20L05

description: In this note we prove that distributors between groupoids in a Barr-exact category E form the bicategory of relations relative to the comprehensive factorization system in Gpd(E). Revised version.
A Normalized Bottleneck Distance on Persistence Diagrams and Homology Preservation under Dimension Reduction
Creators: name: May, Nathan H.
name: Krishnamoorthy, Bala
name: Gambill, Patrick
Publisher: name: arXiv
Year: 2023
Subjects: subject: Computational Geometry (cs.CG)
subject: Machine Learning (cs.LG)
subject: Algebraic Topology (math.AT)
subject: FOS: Computer and information sciences
subject: FOS: Mathematics

description: Persistence diagrams (PDs) are used as signatures of point cloud data. Two clouds of points can be compared using the bottleneck distance d_B between their PDs. A potential drawback of this pipeline is that point clouds sampled from topologically similar manifolds can have arbitrarily large d_B when there is a large scaling between them. This situation is typical in dimension reduction frameworks.
 We define, and study properties of, a new scale-invariant distance between PDs termed normalized bottleneck distance, d_N. In defining d_N, we develop a broader framework called metric decomposition for comparing finite metric spaces of equal cardinality with a bijection. We utilize metric decomposition to prove a stability result for d_N by deriving an explicit bound on the distortion of the bijective map. We then study two popular dimension reduction techniques, Johnson-Lindenstrauss (JL) projections and metric multidimensional scaling (mMDS), and a third class of general biLipschitz mappings. We provide new bounds on how well these dimension reduction techniques preserve homology with respect to d_N. For a JL map f that transforms input X to f(X), we show that d_N(dgm(X),dgm(f(X))) < e, where dgm(X) is the Vietoris-Rips PD of X, and pairwise distances are preserved by f up to the tolerance 0 < ε< 1. For mMDS, we present new bounds for d_B and d_N between PDs of X and its projection in terms of the eigenvalues of the covariance matrix. And for k-biLipschitz maps, we show that d_N is bounded by the product of (k^2-1)/k and the ratio of diameters of X and f(X). Finally, we use computational experiments to demonstrate the increased effectiveness of using the normalized bottleneck distance for clustering sets of point clouds sampled from different shapes.
description: Added computational experiments; published in La Matematica
Accurate Measures of Vaccination and Concerns of Vaccine Holdouts from Web Search Logs
Creators: name: Chang, Serina
name: Fourney, Adam
name: Horvitz, Eric
Publisher: name: arXiv
Year: 2023
Subjects: subject: Computers and Society (cs.CY)
subject: Artificial Intelligence (cs.AI)
subject: FOS: Computer and information sciences

description: To design effective vaccine policies, policymakers need detailed data about who has been vaccinated, who is holding out, and why. However, existing data in the US are insufficient: reported vaccination rates are often delayed or missing, and surveys of vaccine hesitancy are limited by high-level questions and self-report biases. Here, we show how large-scale search engine logs and machine learning can be leveraged to fill these gaps and provide novel insights about vaccine intentions and behaviors. First, we develop a vaccine intent classifier that can accurately detect when a user is seeking the COVID-19 vaccine on search. Our classifier demonstrates strong agreement with CDC vaccination rates, with correlations above 0.86, and estimates vaccine intent rates to the level of ZIP codes in real time, allowing us to pinpoint more granular trends in vaccine seeking across regions, demographics, and time. To investigate vaccine hesitancy, we use our classifier to identify two groups, vaccine early adopters and vaccine holdouts. We find that holdouts, compared to early adopters matched on covariates, are 69% more likely to click on untrusted news sites. Furthermore, we organize 25,000 vaccine-related URLs into a hierarchical ontology of vaccine concerns, and we find that holdouts are far more concerned about vaccine requirements, vaccine development and approval, and vaccine myths, and even within holdouts, concerns vary significantly across demographic groups. Finally, we explore the temporal dynamics of vaccine concerns and vaccine seeking, and find that key indicators emerge when individuals convert from holding out to preparing to accept the vaccine.
Optimal control for a nonlinear stochastic PDE model of cancer growth
Creators: name: Esmaili, Sakine
name: Eslahchi, M. R.
name: Torres, Delfim F. M.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Optimization and Control (math.OC)
subject: FOS: Mathematics
subject: 49J55, 49J20, 49J15, 49K45, 49K20, 49K15

description: We study an optimal control problem for a stochastic model of tumour growth with drug application. This model consists of three stochastic hyperbolic equations describing the evolution of tumour cells. It also includes two stochastic parabolic equations describing the diffusions of nutrient and drug concentrations. Since all systems are subject to many uncertainties, we have added stochastic terms to the deterministic model to consider the random perturbations. Then, we have added control variables to the model according to the medical concepts to control the concentrations of drug and nutrient. In the optimal control problem, we have defined the stochastic and deterministic cost functions and we have proved that the problems have unique optimal controls. For deriving the necessary conditions for optimal control variables, the stochastic adjoint equations are derived. We have proved the stochastic model of tumour growth and the stochastic adjoint equations have unique solutions. For proving the theoretical results, we have used a change of variable which changes the stochastic model and adjoint equations (a.s.) to deterministic equations. Then we have employed the techniques used for deterministic ones to prove the existence and uniqueness of optimal control.
description: This is a preprint of a paper whose final and definite form is published in 'Optimization' at [https://doi.org/10.1080/02331934.2023.2232141]
Spin Space Groups: Full Classification and Applications
Creators: name: Xiao, Zhenyu
name: Zhao, Jianzhou
name: Li, Yanqi
name: Shindou, Ryuichi
name: Song, Zhi-Da
Publisher: name: arXiv
Year: 2023
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: In this work, we exhaust all the spin-space symmetries, which fully characterize collinear, non-collinear, commensurate, and incommensurate spiral magnetism, and investigate enriched features of electronic bands that respect these symmetries. We achieve this by systematically classifying the so-called spin space groups (SSGs) - joint symmetry groups of spatial and spin operations that leave the magnetic structure unchanged. Generally speaking, they are accurate (approximate) symmetries in systems where spin-orbit coupling (SOC) is negligible (finite but weaker than the interested energy scale); but we also show that specific SSGs could remain valid even in the presence of a strong SOC. By representing the SSGs as O($N$) representations, we - for the first time - obtain the complete classifications of 1421, 9542, and 56512 distinct SSGs for collinear ($N=1$), coplanar ($N=2$), and non-coplanar ($N=3$) magnetism, respectively. SSG not only fully characterizes the symmetry of spin d.o.f., but also gives rise to exotic electronic states, which, in general, form projective representations of magnetic space groups (MSGs). Surprisingly, electronic bands in SSGs exhibit features never seen in MSGs, such as nonsymmorphic SSG Brillouin zone (BZ), where SSG operations behave as glide or screw when act on momentum and unconventional spin-momentum locking, which is completely determined by SSG, independent of Hamiltonian details. To apply our theory, we identify the SSG for each of the 1604 published magnetic structures in the MAGNDATA database on the Bilbao Crystallographic Server. Material examples exhibiting aforementioned novel features are discussed with emphasis. We also investigate new types of SSG-protected topological electronic states that are unprecedented in MSGs.
description: accepted in Physical Review X
Occupation type, family demands and mental health: analysis of linked administrative data
Creators: name: Ferry, Finola
name: Rosato, Michael
name: Curran, Emma
name: Leavey, Gerard
Publisher: name: Taylor & Francis
Year: 2023
Subjects: subject: Medicine
subject: Biotechnology
subject: Sociology
subject: FOS: Sociology
subject: Biological Sciences not elsewhere classified
subject: Science Policy
subject: Mental Health

description: While employment generally promotes positive health and wellbeing, some jobs may be less salutogenic than others. Few studies have examined mental health across a range of broadly defined occupation types using a large population sample. To examine the prevalence of mental health problems across a wide range of occupation types, and further examine the association of family demands, controlling for key social determinants and health-related factors. We used linked administrative data from 2011 NI Census returns; NI Properties data; and Enhanced Prescribing Data (EPD) 2011/12. We examined self-reported mental health problems and receipt of psychotropic medication among 553,925 workers aged 25 and 59 years. Self-reported chronic mental ill health was more prevalent among workers in lower paid occupations, while “public- facing” occupations had the highest rates of medication. In fully adjusted models, informal caregivers were less likely to report mental health problems but more likely to be in receipt of psychotropic medication, as were lone parents. The association of family demands also varied across occupational groupings. Future development of mental health at work plans should take cognisance of occupation specific mental health risk and wider family circumstances to support workers’ mental wellbeing most effectively.
A remark on the paper "Properties of intersecting families of ordered sets" by O. Einstein
Creators: name: Oum, Sang-il
name: Wee, Sounggun
Publisher: name: arXiv
Year: 2017
Subjects: subject: Combinatorics (math.CO)
subject: FOS: Mathematics
subject: 05C35

description: O. Einstein (2008) proved Bollobás-type theorems on intersecting families of ordered sets of finite sets and subspaces. Unfortunately, we report that the proof of a theorem on ordered sets of subspaces had a mistake. We prove two weaker variants.
description: 6 pages. Improved bound for Theorem 4
Directional Outlyingness for Multivariate Functional Data
Creators: name: Dai, Wenlin
name: Genton, Marc G.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Methodology (stat.ME)
subject: FOS: Computer and information sciences

description: The direction of outlyingness is crucial to describing the centrality of multivariate functional data. Motivated by this idea, we generalize classical depth to directional outlyingness for functional data. We investigate theoretical properties of functional directional outlyingness and find that the total outlyingness can be naturally decomposed into two parts: magnitude outlyingness and shape outlyingness which represent the centrality of a curve for magnitude and shape, respectively. Using this decomposition, we provide a visualization tool for the centrality of curves. Furthermore, we design an outlier detection procedure based on functional directional outlyingness. This criterion applies to both univariate and multivariate curves and simulation studies show that it outperforms competing methods. Weather and electrocardiogram data demonstrate the practical application of our proposed framework.
description: 36 pages, 7 figures, Computational Statistics & Data Analysis, 2018
Compression with the tudocomp Framework
Creators: name: Dinklage, Patrick
name: Fischer, Johannes
name: Köppl, Dominik
name: Löbel, Marvin
name: Sadakane, Kunihiko
Publisher: name: arXiv
Year: 2017
Subjects: subject: Data Structures and Algorithms (cs.DS)
subject: FOS: Computer and information sciences

description: We present a framework facilitating the implementation and comparison of text compression algorithms. We evaluate its features by a case study on two novel compression algorithms based on the Lempel-Ziv compression schemes that perform well on highly repetitive texts.
Inverting the coupling of the signed Gausssian free field with a loop soup
Creators: name: Lupu, Titus
name: Sabot, Christophe
name: Tarrès, Pierre
Publisher: name: arXiv
Year: 2017
Subjects: subject: Probability (math.PR)
subject: FOS: Mathematics
subject: 60J27, 60J55 (Primary), 60K35, 82B20, 81T25, 81T60 (Secondary)

description: Lupu introduced a coupling between a random walk loop-soup and a Gaussian free field, where the sign of the field is constant on each cluster of loops. This coupling is a signed version of isomorphism theorems relating the square of the GFF to the occupation field of Markovian trajectories. His construction starts with a loop-soup, and by adding additional randomness samples a GFF out of it. In this article we provide the inverse construction: starting from a signed free field and using a self-interacting random walk related to this field, we construct a random walk loop-soup. Our construction relies on the previous work by Sabot and Tarrès, which inverts the coupling from the square of the GFF rather than the signed GFF itself. As a consequence, we also deduce an inversion of the coupling between the random current and the FK-Ising random cluster models introduced by Lupu and Werner.
description: 28 pages, 1 figure
Helimagnon resonances in an intrinsic chiral magnonic crystal
Creators: name: Weiler, Mathias
name: Aqeel, Aisha
name: Mostovoy, Maxim
name: Leonov, Andrey
name: Geprägs, Stephan
name: Gross, Rudolf
name: Huebl, Hans
name: Palstra, Thomas T. M.
name: Goennenwein, Sebastian T. B.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We experimentally study magnetic resonances in the helical and conical magnetic phases of the chiral magnetic insulator Cu$_2$OSeO$_3$ at the temperature $T$=5 K. Using a broadband microwave spectroscopy technique based on vector network analysis, we identify three distinct sets of helimagnon resonances in the frequency range 2 GHz $\leq f \leq$ 20 GHz. The extracted resonance frequencies are in accordance with calculations of the helimagnon bandstructure found in an intrinsic chiral magnonic crystal. The periodic modulation of the equilibrium spin direction that leads to the formation of the magnonic crystal is a direct consequence of the chiral magnetic ordering caused by the Dzyaloshinskii-Moriya interaction. The opening of magnon band-gaps allows for excitation of helimagnons with wave vectors that are multiples of the spiral wave vector.
description: Accepted on November 9th, 2017 for publication at Physical Review Letters (https://journals.aps.org/prl/accepted/5607dY38Rcf14865a08e67543fa3d1c6d0df92c65)
Mycobacterial modulation of macrophage responses to Aspergillus fumigatus
Creators: name: Gonzales Huerta, Luis
Publisher: name: Imperial College London
Year: 2023

description: Over 1 million people have chronic pulmonary aspergillosis secondary to tuberculosis. Furthermore, in patients with cystic fibrosis, Aspergillus fumigatus (Af) has been the most common pathogen associated with mycobacteria. The immunological basis for mycobacterial-fungal coinfection is unknown. However, mycobacterial virulence factors, like lipoarabinomannan, can disrupt host immune pathways and interfere with the clearance of intracellular Af conidia. I hypothesized that the persistence of mycobacteria in the myeloid compartment modulates the immune response against Af. Hence, I aimed to investigate the effect of the Bacillus Calmette-Guerin (BCG) and mycobacterial virulence factors on macrophage responses against Af. Macrophages stimulated with non-mannose-capped lipoarabinomannan (LAM) showed increased cell death and inflammatory cytokine release in a dose-dependent manner. The inflammatory response was characterised by IL-1β release and by increased expression of NLRP3, Caspase-1, gasdermin-D (GSDMD) and cleaved GSDMD (GSDMD-N). Exposure to mannose-capped lipoarabinomannan (ManLAM) did not increase cell death but induced increased expression of NLRP3 and Caspase-1. Time-lapse fluorescence microscopy showed that LAM, ManLAM, and BCG decrease the capacity of macrophages to kill Af conidia within the first 6 hours of infection. Mycobacterial stimuli (LAM and ManLAM) or infection (BCG) upregulated the expression of nucleotide-binding oligomerization domain-containing protein 2 (NOD2), an intracellular sensor that activates downstream the nuclear factor kappa beta (NF-κβ). Pharmacological inhibition of NOD2 in macrophages resolved the hyperinflammatory phenotype observed in the combined infection with mycobacteria and Af. LAM is a TLR-2 agonist, which has been shown to produce a hyperinflammatory phenotype and reduce the capacity of macrophages to clear Af. Additionally, results with BCG-Af coinfection have shown a similar hyperinflammatory response. Overall, these results suggest that mycobacteria enhance the synergic activation of TLR-2 and NOD2 in Af infection, resulting in a hyperinflammatory response. Hyperinflammation subsequently impaired the fungal killing mechanisms, activated the inflammasome, and caused pyroptotic cell death.