Book Review: From Enemy to Friend: Jewish Wisdom and the Pursuit of Peace

Rabbi Amy Eilberg, From Enemy to Friend: Jewish Wisdom and the Pursuit of Peace. Maryknoll, N.Y.: Orbis Books, 2014. Pp. 273, $17.75

Double-Oracle Deep Reinforcement Learning for Handling Exponential Action Space in Sequential Stackelberg Security Games

Standard Stackelberg Security Games (SSGs) assume attackers to be myopic players that select only a single target based on the defender's strategy. In this paper, we consider sequential SSGs, in which attackers launch multiple attacks sequentially. With a sequence of events, however, the defender's action space grows exponentially with the number of time steps, making the problem computationally intractable. To handle this issue, this paper presents the following contributions. First, we use the Double Oracle algorithm to iteratively derive player strategies. Second, we use Advantage Actor-Critic models to approximate best response policies for both players. Lastly, we represent the defender action space compactly with marginal probabilities instead of enumerating all possible actions. Overall, our experiments show that the Double Oracle algorithm not only allows us to search through defender strategies effectively and efficiently, but also provides optimal solutions that outperform other models at scalable settings

At the edge of the Fourth Industrial Revolution: Employees’ perceptions of employment equity from a CIBART perspective

Abstract: Orientation: In accordance with global trends, South Africa is striving for the Fourth Industrial Revolution (4IR). Discourses of employees’ employment equity (EE) perceptions within the 4IR context are studied 25 years after apartheid. Research purpose: The purpose of the study was to understand the systems psychodynamics underneath the surface of employees’ perceptions of EE in South Africa within the context of the 4IR. Motivation for the study: South African workplaces are debated nationally and urged to compete with 4IR changes on a global level. This research focuses on employees’ perceptions of EE underneath the surface and aims at understanding employees’ perceptions through the conflict, identity, boundaries, authority, roles, task (CIBART) model..

“You are my witnesses”: A theological approach to the laws of testimony

The concept of witness spans different literary genres and times of composition. It is not confined to the Old Testament but is also found and expanded upon in rabbinic and New Testament literature. In the New Testament, one of the preferred terms for “believers” is &ogr;ι μαρτυρ&ogr;ι, the witnesses. What is behind the concept of witness and why did it become so meaningful across time and audiences? This study identifies a witness motif and claims that it is deeply rooted in the laws of testimony in the Torah. Exploring these laws in light of ancient Near Eastern parallels, this study argues that ancient law codes, both in ancient Mesopotamian cultures and in the Old Testament, were not primarily meant to be applied in a judicial setting, but rather served a pedagogical purpose. A rhetorical analysis of the laws of testimony in the Torah suggests that the witness motif is aimed at shaping the identity of the addressees of those laws. In the Psalter, this study argues, the “you” to whom the laws are addressed is the “I” who speaks in Psalms. The analysis of a selected group of psalms supports the claim that the witness motif is a powerful tool in shaping the identity of the Psalmist as a Torah-abiding individual. In Isaiah 40–48, the witness motif is enhanced to the point of including, as a corporate entity, all of Israel. Second Isaiah expands the concept of witness proposed by the Torah laws and identifies Israel\u27s mission among the nations: to be a witness of YHWH\u27s mighty deeds in creation and history

POLLEN SIZE AS AN INDICATOR OF PLOIDY LEVEL IN RHEXIA, A SMALL GENUS OF FLOWERING PLANTS ENDEMIC TO THE NORTH AMERICAN COASTAL PLAIN, IN NORTH FLORIDA AND COASTAL GEORGIA**

Rhexia (Melastomataceae) comprises a genus of 13 species that occur primarily in wet areas along the Atlantic coastal plain of North America. These showy plants, known as the meadow beauties, have a complex evolutionary history, with evidence for both ancient and recent hybridization (with several species of putative hybrid origin), as well as polyploidization (four species occur as a variety of cytotypes, e.g. in R. mariana n=11 or 22). Investigations into speciation and evolution in this group require identification of ploidy level for individual specimens. Pollen size in some plant groups is positively correlated with genome size and/or ploidy; in this study we set out to quantify the relationship between pollen grain size and ploidy level in species of Rhexia, potentially providing a means to determine ploidy for future studies without the labor intensive processes and specialized equipment required for chromosome counting and genome estimation by flow cytometry. Seventy-four live plants representing five species of Rhexia were collected from 21 separate populations in Florida and Georgia, and cultivated in the greenhouse. Rhexia mariana. R. cubensis and R. nashii (all of which occur at multiple ploidy levels) were well represented, and a few specimens of the invariably diploid R. alifanus and R. petiolata were also sampled. Pollen from flowers collected in the morning of the first day of anthesis was suspended in a glycerol/water solution on a glass slide, stained with acetocarmine and digitized under 200X magnification. From each image the equatorial diameter of 25 pollen grains was estimated by comparison to standards viewed at similar resolution and measured using a calibrated stage micrometer at the same magnification. We expect to determine whether pollen grain size is correlated with ploidy in three genomically variable species of Rhexia, which will prove useful for future studies of this evolutionarily complex group

Intraspecific and Interspecific Variation in Pollen Size in the Genus Rhexia (Melastomataceae)

Rhexia (Melastomataceae) is a genus of thirteen species occurring primarily in wet areas along the Atlantic coastal plain of North America. These showy flowering plants have a complex evolutionary history, with evidence for ancient and recent hybridization (several species are of putative hybrid origin), as well as polyploidization (four species occur as a variety of cytotypes, e.g. in R. mariana n=11 or 22). Investigations into speciation and evolution in this group require identification of ploidy levels for individual specimens. Pollen size in some plant groups is positively correlated with genome size and/or ploidy; one of our goals is to determine whether pollen grain size can be used to assess the ploidy of individual Rhexia specimens. This initial study focuses on determining inter- and intra-specific variation in pollen grain size for six species of Rhexia. Eighty plants were collected from twenty-three populations in Florida and Georgia and cultivated in the greenhouse. Rhexia mariana, R. cubensis, and R. nashii (all of which occur at multiple ploidy levels) were well represented, and a few specimens of R. alifanus, R. petiolata, and R. nuttallii (which occur only as diploids) were sampled. Anthers collected in the morning on the first day of anthesis were macerated on a glass slide to release pollen, which was suspended in a drop of iodine potassium iodide (IKI) solution. Slides were digitized using a Canon EOS 5DS R camera equipped with a 200 mm lens coupled with a 10X objective lens, and the equatorial diameter of 100 viable pollen grains from each image was measured in Photoshop. Analysis of variance (ANOVA) and Tukey\u27s multiple comparison tests supported significant differences in pollen grain size between certain species of Rhexia, while patterns of intraspecific variation between species of variable ploidy versus those of consistent ploidy remain inconclusive

POLYPLOIDY AND GENOMIC VARIATION IN NORTHERN FLORIDA AND COASTAL GEORGIA POPULATIONS OF RHEXIA, A SMALL GENUS OF FLOWERING WETLAND PLANTS ENDEMIC TO THE NORTH AMERICAN COASTAL PLAIN**

Rhexia, a small genus of flowering plants with 13 species commonly known as meadow beauties, occurs primarily in the North American Coastal Plain (NACP), a region identified in 2016 as the world\u27s 36th global biodiversity hotspot. The evolutionary history of these wetland plants is complicated by repeated hybridization and allopolyploidy events, as evidenced by differing phylogenies of maternal vs. bi-parentally inherited molecular markers. Genome duplication (autopolyploidization) is also common in Rhexia, with a third of the species occurring as polyploid complexes (e.g. in R. nashii n=22 or 33). Thus, this small yet genomically complex group of flowering plants can serve as a model for the study of evolutionary processes in plants of regions with high biodiversity coupled with habitat instability, such as the NACP. Our main goal was to determine cytotypes of differeng ploidy levels from specimens representing various species of Rhexia by counting chromosomes in root tip meristem cells, to provide calibration standards for efficient genome size estimation using flow cytometry for future, more extensive studies. Living specimens of 143 Rhexia plants comprising five Rhexia species and two putative hybrids were collected from 21 populations in northern Florida and coastal Georgia, and reared in greenhouses. Root tips were harvested during the growing season, immediately pretreated with 8-hydroxyquinoline to enhance spreading of mitotic chromosomes, fixed in 3:1 ethanol-glacial acetic acid, and stored in 70% ethanol. Root tip meristem cells were isolated and squashed on glass slides, stained with aceto-orcein or DAPI, and examined via light and fluorescent microscopy. Discrete cells with well-defined chromosomes were imaged and counted. We expect to establish cytotypes for multiple specimens of each represented species for varying ploidy levels, thus providing reliable standards to later be used for cytotyping via flow cytometry