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1. The most common queueing theory questions asked by computer systems practitioners

   https://doi.org/10.1145/3543146.3543148  

   Harchol-Balter, Mor; Scully, Ziv (June 2022, ACM SIGMETRICS Performance Evaluation Review)

   This document examines five performance questions which are repeatedly asked by practitioners in industry: (i) My system utilization is very low, so why are job delays so high? (ii) What should I do to lower job delays? (iii) How can I favor short jobs if I don't know which jobs are short? (iv) If some jobs are more important than others, how do I negotiate importance versus size? (v) How do answers change when dealing with a closed-loop system, rather than an open system? All these questions have simple answers through queueing theory. This short paper elaborates on the questions and their answers. To keep things readable, our tone is purposely informal throughout. For more formal statements of these questions and answers, please see [14]. 

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2. Review: Using physiologically based models to predict population responses to phytochemicals by wild vertebrate herbivores

   https://doi.org/10.1017/S1751731118002264  

   Forbey, J. S.; Liu, R.; Caughlin, T. T.; Matocq, M. D.; Vucetich, J. A.; Kohl, K. D.; Dearing, M. D.; Felton, A. M. (December 2018, animal)

   To understand how foraging decisions impact individual fitness of herbivores, nutritional ecologists must consider the complex in vivo dynamics of nutrient–nutrient interactions and nutrient–toxin interactions associated with foraging. Mathematical modeling has long been used to make foraging predictions (e.g. optimal foraging theory) but has largely been restricted to a single currency (e.g. energy) or using simple indices of nutrition (e.g. fecal nitrogen) without full consideration of physiologically based interactions among numerous co-ingested phytochemicals. Here, we describe a physiologically based model (PBM) that provides a mechanistic link between foraging decisions and demographic consequences. Including physiological mechanisms of absorption, digestion and metabolism of phytochemicals in PBMs allows us to estimate concentrations of ingested and interacting phytochemicals in the body. Estimated phytochemical concentrations more accurately link intake of phytochemicals to changes in individual fitness than measures of intake alone. Further, we illustrate how estimated physiological parameters can be integrated with the geometric framework of nutrition and into integral projection models and agent-based models to predict fitness and population responses of vertebrate herbivores to ingested phytochemicals. The PBMs will improve our ability to understand the foraging decisions of vertebrate herbivores and consequences of those decisions and may help identify key physiological mechanisms that underlie diet-based ecological adaptations. 

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3. Metabolism Shapes the Cell

   https://doi.org/10.1128/JB.00039-17  

   Sperber, Anthony M.; Herman, Jennifer K.; Margolin, William (May 2017, Journal of Bacteriology)

   ABSTRACT More than 5 decades of work support the idea that cell envelope synthesis, including the inward growth of cell division, is tightly coordinated with DNA replication and protein synthesis through central metabolism. Remarkably, no unifying model exists to account for how these fundamentally disparate processes are functionally coupled. Recent studies demonstrate that proteins involved in carbohydrate and nitrogen metabolism can moonlight as direct regulators of cell division, coordinate cell division and DNA replication, and even suppress defects in DNA replication. In this minireview, we focus on studies illustrating the intimate link between metabolism and regulation of peptidoglycan (PG) synthesis during growth and division, and we identify the following three recurring themes. (i) Nutrient availability, not growth rate, is the primary determinant of cell size. (ii) The degree of gluconeogenic flux is likely to have a profound impact on the metabolites available for cell envelope synthesis, so growth medium selection is a critical consideration when designing and interpreting experiments related to morphogenesis. (iii) Perturbations in pathways relying on commonly shared and limiting metabolites, like undecaprenyl phosphate (Und-P), can lead to pleotropic phenotypes in unrelated pathways. 

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4. Quantifying intermediary processes in ecology using causal mediation analyses

   https://doi.org/10.32942/X2R628  

   Correia, Hannah; Dee, Laura; Ferraro, Paul (May 2024, EcoEvoRxiv - Accepted in Biology Letters)

   Ecologists seek to understand the intermediary ecological processes through which changes in one attribute in a system affect other attributes. Yet, quantifying the causal effects of these mediating processes in ecological systems is challenging. Researchers must define what they mean by a “mediated effect”, determine what assumptions are required to estimate mediation effects without bias, and assess whether these assumptions are credible for a study. To address these challenges, scholars in fields outside of ecology have made significant advances in mediation analysis over the past three decades. Here, we bring these advances to the attention of ecologists, for whom understanding mediating processes and deriving causal inferences are important for testing theory and developing resource management and conservation strategies. To illustrate both the challenges and the advances in quantifying mediation effects, we use a hypothetical ecological study. With this study, we show how common research designs used in ecology to detect and quantify mediation effects may have biases and how these biases can be addressed through alternative designs. Throughout the review, we highlight how causal claims rely on causal assumptions, and we illustrate how different designs or definitions of mediation effects can relax some of these assumptions. In contrast to statistical assumptions, causal assumptions are not verifiable from data, so we also describe procedures that researchers can use to assess the sensitivity of a study’s results to potential violations of its causal assumptions. The advances in causal mediation analyses reviewed herein will provide ecological researchers with approaches to clearly communicate the causal assumptions necessary for valid inferences and examine potential violations to these assumptions, which will enable rigorous and reproducible explanations of intermediary processes in ecology. 

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5. 94 different countries? Time, place, and variations in federal criminal justice

   https://doi.org/https://doi.org/10.15779/Z38KW57J58  

   Lynch, Mona (January 2018, Berkeley journal of criminal law)

   null (Ed.)

   Frank Zimring and Gordon Hawkins’s 1991 book, The Scale of Imprisonment, was a pioneering intellectual effort to explain what was then just coming into view to social scientists and legal scholars: the massive growth and transformation of American criminal justice, particularly as manifested in what soon came to be called mass incarceration. Zimring and Hawkins endeavored to disentangle multiple forces in play, ranging from formal law, to local and regional legal norms, to a series of broader social and political transformations. In doing so, Zimring and Hawkins set out to disentangle the complex, multi-jurisdictional political and legal structures that govern imprisonment policy in the U.S. In this Article, I apply their insights about locale-based variations in criminal justice operations over time to the case of federal sentencing. Specifically, I empirically examine variations in how the “criminal history” provision of the federal sentencing guidelines is applied as a function of both time and place to demonstrate the limits of formal law in accounting for punishment outcomes. In doing so, I hope to shed additional light on how vast differences in legal practices and outcomes are produced, especially in response to top-down legal change. 

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