On McTaggart’s Theory of Time

J. McTaggart argues that the philosophical conception of time is constituted by the notions of fluid and static time. Since, on his view, neither notion is philosophically viable, he concludes that time is nothing but an illusion that arises from our distorted perception of essentially atemporal reality. In the paper, I argue that despite McTaggart’s failure to prove the unreality of time as such, he does succeed in establishing his lesser claim that the concept of fluid time is without any ontological import whatsoever

Using zebrafish (Danio rerio) to study the behavioral impacts of early bisphenol F exposure reveals decreased swim speed, increased distance between fish, and increased freezing behaviors

The widespread use of endocrine disrupting chemicals (EDCs) has been a source of concern because of their various effects on the endocrine system. These effects include metabolic disorders, complications in reproductive health, hormone-related cancers, and neurodevelopmental disorders. Of particular concern is bisphenol A (BPA), a synthetic compound commonly found in consumer products such as water bottles, thermal receipt paper, and epoxy resins used in processed food packaging. Previous studies have shown that BPA can mimic estrogen through a variety of mechanisms and thus elicit an endocrine response. Some manufacturers have responded by removing BPA from their products; however, studies using a replacement compound bisphenol S have reported it to be just as, if not more, dangerous. The use of zebrafish (Danio rerio) larvae as a model organism allows for the effects of bisphenol exposure to be rapidly quantified through a simple behavioral assay. In studies involving bisphenol exposure, the use of zebrafish has demonstrated reproductive, developmental, endocrine, and behavioral effects. The study of bisphenol F, yet another endocrine disruptor that has become a replacement for BPA in consumer products, is highly important to public safety

Effects of endocrine-disrupting chemical exposure on zebrafish ovarian follicles

The process of oocyte maturation involves both nuclear and cytoplasmic events that are essential for the production of viable eggs and subsequent fertilization in sexually reproducing animals. In zebrafish, oocyte nuclear maturation (meiotic resumption) is marked by a transition from opaque to translucent ovarian follicles. This transition is called clearing and results from germinal vesicle breakdown (GVBD) and the transformation of vitellogenin into yolk proteins. Oocyte maturation can be perturbed by endocrine-disrupting chemicals (EDCs). These EDCs have been broadly shown to interfere with reproductive development. Many herbicides and pesticides used agriculturally act as EDCs. These chemicals can enter aquatic ecosystems via runoff and erosion. To evaluate the effects of EDCs on zebrafish oocyte maturation, zebrafish ovarian follicles were cultured and exposed to various concentrations of either atrazine, 2,4-D, or diazinon. Follicles were evaluated at 2, 3, and 4 hours for size and viability, but clearing was assessed only at 4 hours post-exposure. Atrazine and diazinon significantly reduced follicle clearing at the tested concentrations. No effect was observed with 2,4-D exposure. At low enough concentrations, none of the chemicals produced endocrine-disrupting effects. The results suggest that at or above environmentally relevant concentrations, some EDCs impair oocyte maturation in exposed zebrafish follicles. The results support the need to monitor EDC exposure to prevent harmful effects not only on aquatic organisms, but also on humans and wildlife that are also exposed to these contaminants

Cluster growth in the dynamical Erd\H{o}s-R\'{e}nyi process with forest fires

We investigate the growth of clusters within the forest fire model of R\'{a}th and T\'{o}th [22]. The model is a continuous-time Markov process, similar to the dynamical Erd\H{o}s-R\'{e}nyi random graph but with the addition of so-called fires. A vertex may catch fire at any moment and, when it does so, causes all edges within its connected cluster to burn, meaning that they instantaneously disappear. Each burned edge may later reappear. We give a precise description of the process $C_t$ of the size of the cluster of a tagged vertex, in the limit as the number of vertices in the model tends to infinity. We show that $C_t$ is an explosive branching process with a time-inhomogeneous offspring distribution and instantaneous return to $1$ on each explosion. Additionally, we show that the characteristic curves used to analyse the Smoluchowski-type coagulation equations associated to the model have a probabilistic interpretation in terms of the process $C_t$.Comment: 31 page

Relational Investing: The Worker's Perspective

Workers who hold a firm's stock make decisions other than those that pure capital owners would make, but there exist institutions and compensation packages that will generally lead workers to favor efficient firm decisions. Workers care about their firm-specific rents and may seek shares in their firm to use them to protect those rents. Their views toward firm decisions will differ depending on their firm-specific human capital and tenure in the firm. The workers most favorable to efficient firm decisions are the very young and very old, who have the least amount to lose in employment rent and those with larger shares of ownership. An appropriate severance pay policy will induce workers to choose efficient outcomes even if it calls for their own layoffs. Single company based defined contribution pension funds, which hold shares in their own firm, are likely to tilt worker- owners to favor efficient decisions when layoffs and other changes are modest, but not when the changes are huge. Pension funds are more likely to buy up shares and successfully change behavior in small firms, in firms that are highly levered, and when the investment community has diverse views on the benefit from changing a firm's current irresponsible policies.

Evaluating the Effects of Bisphenols F and S with Respect to Bisphenol A on Primordial Germ Cell Migration in Zebrafish (Danio rerio) Embryos Using Immunofluorescence Microscopy

Primordial Germ Cell (PGC) migration occurs in early embryonic development and is highly conserved across taxa. PGC migration occurs within the first 24 hours post fertilization (hpf) in zebrafish, making the organism an efficient model for observing the migration pathway. Proper PGC migration is necessary for normal gonad development and, in some species, sex determination. Disruption of this process leads to defects in gonad formation and abnormal sex determination and differentiation. Studies show that endocrine-disrupting chemicals such as bisphenol A (BPA) disrupt PGC migration in zebrafish. BPA is an estrogenic compound that has been linked to a variety of human diseases, including various cancers, diabetes, reproductive disorders, obesity, and cardiovascular diseases. It is one of the most widely used synthetic compounds worldwide, as it is used to make polycarbonate plastics. Many studies provide evidence of the harmful effects of BPA on living organisms. In response, manufacturers have started to use replacements such as bisphenol F (BPF) and bisphenol S (BPS). However, due to their structural similarity, it is likely that BPF and BPS are just as harmful to organisms as BPA. In this study, we use antibody staining and immunofluorescence microscopy to confirm that BPA exposure results in abnormal PGC migration in zebrafish embryos, as previously studied, and to illustrate that BPF and BPS exposure results in similar PGC migration defects

Language as the Medium: A Literature Review. Harnessing the Prolific Power of Dramatic Language as a Therapeutic Tool in Drama Therapy

Language in and of the theatre, with its palate of variegated writing styles and playwrights from throughout time, has the potential to be harnessed, focused, and systematized for use as a therapeutic tool within drama therapy – the field’s artistic medium. Drama therapy could benefit from having a specific medium germane to its artform which has the potential to provide practitioners with a common resource and means of communication, assessment, diagnosis, and treatment planning, as well as align the field with other creative arts therapies. Language encompasses all forms of human communication – speaking, writing, signing, gesturing, expressing facially – and voice and speech training are crucial components of holistic training for actors. This thesis positions language as the primary medium of the theatre by examining multiple and disputed theories of theatre origins as well as interrelated theories of the theatre as an entity in order to distinguish drama as an evolutionary means of human communication. Furthermore, it probes the basic clinical foundations of speech-language pathology, which possesses a wealth of research and theory already supporting language assessment and treatment, in addition to basic biology and neuroanatomy surrounding speech, speech production, and development in order to ground the argument in pre-existing medical and clinical knowledge. Herein, I propose future directions and lay the groundwork for continued research and structured theory development

On A and B Theories of Time

Our metaphysical notion of temporality is exhausted by the concepts of fluid and static time. Following James Ellis McTaggart, philosophers refer to these times as the A-series and B-series respectively. To have a metaphysical argument against the reality of time as such, therefore, separate arguments against the reality of both temporal series are required. In the dissertation, I shall offer a number of both types of arguments. In the first chapter, McTaggart’s program is assessed. It is concluded that McTaggart has an argument against the reality of the A-series, but does not have one against the reality of the B-series. In the second chapter, additional arguments against the reality of the A-series, as well as against hybrid A/B series, are presented. In the third chapter, it is argued that the B-series is as unreal as its counterpart, the A-series, is. This outcome leaves us with the following philosophical predicament: on the one hand, our philosophical notion of time is exhausted by the concepts of fluid and static time; on the other hand, neither concept, nor any of their amalgamation, is adequate to give us a coherent metaphysical theory of time. The dilemma, I believe, is a sufficient reason for the conclusion that time, as it is conceived by philosophers, is not part of physical reality