73 research outputs found
Imbalanced Domain Generalization for Robust Single Cell Classification in Hematological Cytomorphology
Accurate morphological classification of white blood cells (WBCs) is an
important step in the diagnosis of leukemia, a disease in which nonfunctional
blast cells accumulate in the bone marrow. Recently, deep convolutional neural
networks (CNNs) have been successfully used to classify leukocytes by training
them on single-cell images from a specific domain. Most CNN models assume that
the distributions of the training and test data are similar, i.e., that the
data are independently and identically distributed. Therefore, they are not
robust to different staining protocols, magnifications, resolutions, scanners,
or imaging protocols, as well as variations in clinical centers or patient
cohorts. In addition, domain-specific data imbalances affect the generalization
performance of classifiers. Here, we train a robust CNN for WBC classification
by addressing cross-domain data imbalance and domain shifts. To this end, we
use two loss functions and demonstrate the effectiveness on out-of-distribution
(OOD) generalization. Our approach achieves the best F1 macro score compared to
other existing methods, and is able to consider rare cell types. This is the
first demonstration of imbalanced domain generalization in hematological
cytomorphology and paves the way for robust single cell classification methods
for the application in laboratories and clinics.Comment: Published as a ICLR 2023 workshop paper: What do we need for
successful domain generalization
A Continual Learning Approach for Cross-Domain White Blood Cell Classification
Accurate classification of white blood cells in peripheral blood is essential
for diagnosing hematological diseases. Due to constantly evolving clinical
settings, data sources, and disease classifications, it is necessary to update
machine learning classification models regularly for practical real-world use.
Such models significantly benefit from sequentially learning from incoming data
streams without forgetting previously acquired knowledge. However, models can
suffer from catastrophic forgetting, causing a drop in performance on previous
tasks when fine-tuned on new data. Here, we propose a rehearsal-based continual
learning approach for class incremental and domain incremental scenarios in
white blood cell classification. To choose representative samples from previous
tasks, we employ exemplar set selection based on the model's predictions. This
involves selecting the most confident samples and the most challenging samples
identified through uncertainty estimation of the model. We thoroughly evaluated
our proposed approach on three white blood cell classification datasets that
differ in color, resolution, and class composition, including scenarios where
new domains or new classes are introduced to the model with every task. We also
test a long class incremental experiment with both new domains and new classes.
Our results demonstrate that our approach outperforms established baselines in
continual learning, including existing iCaRL and EWC methods for classifying
white blood cells in cross-domain environments.Comment: Accepted for publication at workshop on Domain Adaptation and
Representation Transfer (DART) in International Conference on Medical Image
Computing and Computer Assisted Intervention (MICCAI 2023
Inhibition of rainbow trout acetylcholinesterase by aqueous and suspended particle-associated organophosphorous insecticides
Spraydrift and edge-of-field runoff are important routes of pesticide entry into streams. Pesticide contamination originating from spraydrift usually resides in the water phase, while pesticides in contaminated runoff are to a large extent associated with suspended particles (SPs). The effects of two organophosphorous insecticides (OPs), chloropyrifos (CPF) and azinphos-methyl (AZP), on acetylcholinesterase (AChE) activity in rainbow trout were compared between two exposure scenarios, simulating spraydrift- and runoff-borne contamination events in the Lourens River (LR), Western Cape, South Africa. NOECs of brain AChE inhibition, determined after 1 h of exposure followed by 24 h of recovery, were 0.33 μg l−1 for aqueous CPF, 200 mg kg−1 for SP-associated CPF and 20 mg kg−1 for SP-associated AZP (at 0.5 g l−1 SP). The highest aqueous AZP concentration tested (3.3 μg l−1) was without significant effects. Previously reported peak levels of aqueous CPF in the LR (not, vert, similar0.2 μg l−1) are close to its NOEC (this study), suggesting a significant toxicological risk to fish in the LR. By contrast, reported levels of SP-associated OPs in the LR are 20–200-fold lower than their NOECs (this study). In a comparative in situ study, trout were exposed for seven days at agricultural (LR2, LR3) and upstream reference (LR1) sites. No runoff occurred during the study. Brain AChE was significantly inhibited at LR3. However, OP levels at LR3 (CPF 0.01 μg l−1; AZP 0.14 μg l−1) were minor compared to concentrations having effects in the laboratory (see above). Additionally, muscle AChE activity was significantly higher in caged trout from LR1 than in animals maintained in laboratory tanks
Impact of physical activity on activity of daily living in moderate to severe dementia: a critical review
The objectives of this study were to describe the different modalities of physical activity programs designed for moderate to severe dementia and to identify their impact on functional independence in activities of daily living (ADL). A critical review of randomized controlled trials related to the impact of physical activity programs in moderately to severely demented persons on ADL performance and meta-analysis of the identified studies were performed. Among the 303 identified articles, five responded to the selection criteria. Four out of the five studies demonstrated limited methodological quality. In one high-quality study, physical activity programs significantly delayed deterioration of ADL performance. The program components and ADL assessment tools vary widely across studies. Although the proposed treatments have not proven their efficiency in improving the ADL status of the patients, they were able to limit the decline in ADL functioning. Future research is warranted in order to identify clinically relevant modalities for physical activity programs for people with moderate to severe dementia
Evolution of reproductive development in the volvocine algae
The evolution of multicellularity, the separation of germline cells from sterile somatic cells, and the generation of a male–female dichotomy are certainly among the greatest innovations of eukaryotes. Remarkably, phylogenetic analysis suggests that the shift from simple to complex, differentiated multicellularity was not a unique progression in the evolution of life, but in fact a quite frequent event. The spheroidal green alga Volvox and its close relatives, the volvocine algae, span the full range of organizational complexity, from unicellular and colonial genera to multicellular genera with a full germ–soma division of labor and male–female dichotomy; thus, these algae are ideal model organisms for addressing fundamental issues related to the transition to multicellularity and for discovering universal rules that characterize this transition. Of all living species, Volvox carteri represents the simplest version of an immortal germline producing specialized somatic cells. This cellular specialization involved the emergence of mortality and the production of the first dead ancestors in the evolution of this lineage. Volvocine algae therefore exemplify the evolution of cellular cooperation from cellular autonomy. They also serve as a prime example of the evolution of complex traits by a few successive, small steps. Thus, we learn from volvocine algae that the evolutionary transition to complex, multicellular life is probably much easier to achieve than is commonly believed
Nicht nur technische Innovationen, auch neue Gruppen-Formate beschleunigen den Weg zur Nachhaltigkeit in Wirtschaft und Staat
Energieeffizienz-Netzwerke werden seit rund zwanzig Jahren in Unternehmen in Deutschland und Österreich eingesetzt – in der Schweiz sogar schon seit 30 Jahren. Die beschleunigte Effizienz-Verbesserung und die schnelleren CO2-Emissionsminderungen gegenüber dem Durchschnitt nicht teilnehmender Unternehmen sind auf sozial- und individualpsychologische sowie ökonomische Wirkmechanismen zurückzuführen.
Ein Ausblick auf die weitere Entwicklung dieser Netzwerke in anderen Industrie- und Schwellen-Ländern und für Gebietskörperschaften und andere Institutionen bestätigt die Universalität dieses Policy-Instruments und der beobachteten Zusammenhänge.
In einer Dekade, in der der Klimaschutz extrem beschleunigt werden muss, hat dieser sozialwissenschaftlich belegte "Beschleuniger" seinen möglichen Beitrag zu leisten
Dexhand : a Space qualified multi-fingered robotic hand
Despite the progress since the first attempts of
mankind to explore space, it appears that sending man in space
remains challenging. While robotic systems are not yet ready to
replace human presence, they provide an excellent support for
astronauts during maintenance and hazardous tasks. This paper
presents the development of a space qualified multi-fingered
robotic hand and highlights the most interesting challenges.
The design concept, the mechanical structure, the electronics
architecture and the control system are presented throughout
this overview paper
- …