Studies of chimeras and in vivo development demonstrate that cell lineages are often quite variable, apparently in response to chance perturbations. This points to an apparent contradiction: although individual cells are the units of genetic information and differentiation, not all cellular events need be precise for the development of functional organisms. The social organization of ants can serve as a metaphor that helps understand the mechanisms that underlie such development. Ants suggest that continued cellular interactions and environmental conditions could specify (...) the proportion and general location of specialized units. Leaf venation is used as a concrete example of this general principle. A signal produced continuously by all cells specifies a requirement for vein differentiation. The cells that respond by differentiation then transport the signal away from the leaf; this removal acting as a feedback indicating that the requirement is being met. Because transport increases during vein differentiation, early initiation occurs in excess and vein ‘competition’ for the signal assures an acceptable outcome. Such specification would be robust since it does not depend on events in any single cell, and chance events, rather than being corrected or reversed, may be built upon in reaching an expected, collective phenotype. The absence of detailed information preceding development distinguishes this hypothesis from the common alternatives of a program or blueprint. Collective specification would have important implications for developmental plasticity and evolution. BioEssays 25:897–903, 2003. © 2003 Wiley Periodicals, Inc. (shrink)

Conceptual developments have defined concrete questions about the timing and precise location of cellular pattern formation. Plants in general, and the trichomes of Arabidopsis in particular, are remarkably suited for research on these problems. Genetic analysis requires the quantitative characterizations of the developmental processes by which patterning occurs. Larkin et al.(1) have provided measures of the non‐random distances between trichomes. They have also obtained evidence about the cell lineages leading to trichome development, and this evidence constrains the possible role of (...) intracellular programs. Continued genetic analysis may call for the identification of mutations that are expressed only during development and whose effects are corrected before the phenotype matures. (shrink)

In light of the widespread use of algorithmic (intelligent) systems across numerous domains, there is an increasing awareness about the need to explain their underlying decision-making process and resulting outcomes. Since oftentimes these systems are being considered as black boxes, adding explanations to their outcomes may contribute to the perception of their transparency and, as a result, increase users’ trust and fairness perception towards the system, regardless of its actual fairness, which can be measured using various fairness tests and measurements. (...) Different explanation styles may have a different impact on users’ perception of fairness towards the system and on their understanding of the outcome of the system. Hence, there is a need to understand how various explanation styles may impact non-expert users’ perceptions of fairness and understanding of the system’s outcome. In this study we aimed at fulfilling this need. We performed a between-subject user study in order to examine the effect of various explanation styles on users’ fairness perception and understanding of the outcome. In the experiment we examined four known styles of textual explanations (case-based, demographic-based, input influence-based and sensitivity-based) along with a new style (certification-based) that reflect the results of an auditing process of the system. The results suggest that providing some kind of explanation contributes to users’ understanding of the outcome and that some explanation styles are more beneficial than others. Moreover, while explanations provided by the system are important and can indeed enhance users’ perception of fairness, their perception mainly depends on the outcome of the system. The results may shed light on one of the main problems in explainability of algorithmic systems, which is choosing the best explanation to promote users’ fairness perception towards a particular system, with respect to the outcome of the system. The contribution of this study is reflected in the new and realistic case study that was examined, in the creation and evaluation of a new explanation style that can be used as the link between the actual (computational) fairness of the system and users’ fairness perception and in the need of analyzing and evaluating explanations while taking into account the outcome of the system. (shrink)

The unprecedented prowess of measurement techniques provides a detailed, multi‐scale look into the depths of living systems. Understanding these avalanches of high‐dimensional data—by distilling underlying principles and mechanisms—necessitates dimensional reduction. We propose that living systems achieve exquisite dimensional reduction, originating from their capacity to learn, through evolution and phenotypic plasticity, the relevant aspects of a non‐random, smooth physical reality. We explain how geometric insights by mathematicians allow one to identify these genuine hallmarks of life and distinguish them from universal properties (...) of generic data sets. We illustrate these principles in a concrete example of protein evolution, suggesting a simple general recipe that can be applied to understand other biological systems. (shrink)

Corpus of Mesopotamian Anti-Witchcraft Rituals. By Tsvi Abusch, Daniel Schwemer, Mikko Luukko, and Greta van Buylaere. Ancient Magic and Divination, vol. 8.3. Leiden: briLL, 2020. Pp. xx + 507, 68 pls. $297. Corpus of Mesopotamian Anti-Witchcraft Rituals: Glossaries and Indices. By Greta van Buylaere and Mikko Luukko. Ancient Magic and Divination, vol. 8.4. Leiden: briLL, 2020. Pp. viii + 163. $127.