2,382 research outputs found
Development and Function of Dendritic Cell Subsets
Classical dendritic cells (cDCs) form a critical interface between innate and adaptive immunity. As myeloid immune cell sentinels, cDCs are specialized in the sensing of pathogen challenges and cancer. They translate the latter for T cells into peptide form. Moreover, cDCs provide additional critical information on the original antigen context to trigger a diverse spectrum of appropriate protective responses. Here we review recent progress in our understanding of cDC subsets in mice. We will discuss cDC subset ontogeny and transcription factor dependencies, as well as emerging functional specializations within the cDC compartment in lymphoid and nonlymphoid tissues
Spectral Distribution Aware Image Generation
Recent advances in deep generative models for photo-realistic images have led
to high quality visual results. Such models learn to generate data from a given
training distribution such that generated images can not be easily
distinguished from real images by the human eye. Yet, recent work on the
detection of such fake images pointed out that they are actually easily
distinguishable by artifacts in their frequency spectra. In this paper, we
propose to generate images according to the frequency distribution of the real
data by employing a spectral discriminator. The proposed discriminator is
lightweight, modular and works stably with different commonly used GAN losses.
We show that the resulting models can better generate images with realistic
frequency spectra, which are thus harder to detect by this cue.Comment: Accepted at AAAI 2021 (conference version). Code:
https://github.com/steffen-jung/SpectralGA
Non-Identical Twins – Microglia and Monocyte-Derived Macrophages in Acute Injury and Autoimmune Inflammation
The brain has been commonly regarded as a “tissue behind walls.” Appearance of immune cells in the brain has been taken as a sign of pathology. Moreover, since infiltrating monocyte-derived macrophages and activated resident microglia were indistinguishable by conventional means, both populations were considered together as inflammatory cells that should be mitigated. Yet, because the microglia permanently reside in the brain, attributing to them negative properties evoked an ongoing debate; why cells that are supposed to be the brain guardians acquire only destructive potential? Studies over the last two decades in the immune arena in general, and in the context of central nervous system pathology in particular, have resulted in a paradigm shift toward a more balanced appreciation of the contributions of immune cells in the context of brain maintenance and repair, and toward the recognition of distinct roles of resident microglia and infiltrating monocyte-derived macrophages
Learning Where To Look -- Generative NAS is Surprisingly Efficient
The efficient, automated search for well-performing neural architectures
(NAS) has drawn increasing attention in the recent past. Thereby, the
predominant research objective is to reduce the necessity of costly evaluations
of neural architectures while efficiently exploring large search spaces. To
this aim, surrogate models embed architectures in a latent space and predict
their performance, while generative models for neural architectures enable
optimization-based search within the latent space the generator draws from.
Both, surrogate and generative models, have the aim of facilitating
query-efficient search in a well-structured latent space. In this paper, we
further improve the trade-off between query-efficiency and promising
architecture generation by leveraging advantages from both, efficient surrogate
models and generative design. To this end, we propose a generative model,
paired with a surrogate predictor, that iteratively learns to generate samples
from increasingly promising latent subspaces. This approach leads to very
effective and efficient architecture search, while keeping the query amount
low. In addition, our approach allows in a straightforward manner to jointly
optimize for multiple objectives such as accuracy and hardware latency. We show
the benefit of this approach not only w.r.t. the optimization of architectures
for highest classification accuracy but also in the context of hardware
constraints and outperform state-of-the-art methods on several NAS benchmarks
for single and multiple objectives. We also achieve state-of-the-art
performance on ImageNet. The code is available at
http://github.com/jovitalukasik/AG-Net .Comment: Accepted to European Conference on Computer Vision 202
Severe B Cell Deficiency in Mice Lacking the Tec Kinase Family Members Tec and Btk
The cytoplasmic protein tyrosine kinase Tec has been proposed to have important functions in hematopoiesis and lymphocyte signal transduction. Here we show that Tec-deficient mice developed normally and had no major phenotypic alterations of the immune system. To reveal potential compensatory roles of other Tec kinases such as Bruton's tyrosine kinase (Btk), Tec/Btk double-deficient mice were generated. These mice exhibited a block at the B220+CD43+ stage of B cell development and displayed a severe reduction of peripheral B cell numbers, particularly immunoglobulin (Ig)MloIgDhi B cells. Although Tec/Btknull mice were able to form germinal centers, the response to T cell–dependent antigens was impaired. Thus, Tec and Btk together have an important role both during B cell development and in the generation and/or function of the peripheral B cell pool. The ability of Tec to compensate for Btk may also explain phenotypic differences in X-linked immunodeficiency (xid) mice compared with human X-linked agammaglobulinemia (XLA) patients
FrequencyLowCut Pooling -- Plug & Play against Catastrophic Overfitting
Over the last years, Convolutional Neural Networks (CNNs) have been the
dominating neural architecture in a wide range of computer vision tasks. From
an image and signal processing point of view, this success might be a bit
surprising as the inherent spatial pyramid design of most CNNs is apparently
violating basic signal processing laws, i.e. Sampling Theorem in their
down-sampling operations. However, since poor sampling appeared not to affect
model accuracy, this issue has been broadly neglected until model robustness
started to receive more attention. Recent work [17] in the context of
adversarial attacks and distribution shifts, showed after all, that there is a
strong correlation between the vulnerability of CNNs and aliasing artifacts
induced by poor down-sampling operations. This paper builds on these findings
and introduces an aliasing free down-sampling operation which can easily be
plugged into any CNN architecture: FrequencyLowCut pooling. Our experiments
show, that in combination with simple and fast FGSM adversarial training, our
hyper-parameter free operator significantly improves model robustness and
avoids catastrophic overfitting
Local Spherical Harmonics Improve Skeleton-Based Hand Action Recognition
Hand action recognition is essential. Communication, human-robot
interactions, and gesture control are dependent on it. Skeleton-based action
recognition traditionally includes hands, which belong to the classes which
remain challenging to correctly recognize to date. We propose a method
specifically designed for hand action recognition which uses relative angular
embeddings and local Spherical Harmonics to create novel hand representations.
The use of Spherical Harmonics creates rotation-invariant representations which
make hand action recognition even more robust against inter-subject differences
and viewpoint changes. We conduct extensive experiments on the hand joints in
the First-Person Hand Action Benchmark with RGB-D Videos and 3D Hand Pose
Annotations, and on the NTU RGB+D 120 dataset, demonstrating the benefit of
using Local Spherical Harmonics Representations. Our code is available at
https://github.com/KathPra/LSHR_LSHT
- …