Threshold Amount Research Articles

ROS as Signaling Molecules to Initiate the Process of Plant Acclimatization to Abiotic Stress

During their life cycle, plants constantly respond to environmental changes. Abiotic stressors affect the photosynthetic and respiratory processes of plants. Reactive oxygen species (ROS) are produced during aerobic metabolism and play an important role as regulatory mediators in signaling processes, activating the plant’s protective response to abiotic stress and restoring “oxidation-reduction homeostasis”. Cells develop normally if the rates of ROS production and the ability to neutralize them are balanced. To implement oxidation-reduction signaling, this balance must be disrupted either by an increase in ROS concentration or a decrease in the activity of one or more antioxidant systems. Under abiotic stress, plants accumulate excessive amounts of ROS, and if the ROS content exceeds the threshold amount dangerous for living organisms, it can lead to damage to all major cellular components. Adaptive resistance of plants to abiotic stressors depends on a set of mechanisms of adaptation to them. The accumulation of ROS in the cell depends on the type of abiotic stress, the strength of its impact on the plant, the duration of its impact, and the recovery period. The aim of this review is to provide a general understanding of the processes occurring during ROS homeostasis in plants, oxidation-reduction processes in cellular compartments in response to abiotic stress, and the participation of ROS in signaling processes activating adaptation processes to abiotic stress.

Economic Impact of Low Power Factor on Institutions: a Case Study of Assosa University Building

Power factor is a measure of how efficiently electric power is consumed. It is the result of phase difference between voltage and current at different stages of power system. It’s the ratio of active power or useful power to apparent power. The apparent power consists of both the active power and reactive power. If the reactive power increase in a power system, the power factor becomes low. Low power factor can affect the power system quality and the consumer to suffer in paying additional penalty charge for utility if it drops below the predetermined threshold amount. In this study, the bill data record indicates there was low power factor in each month from different energy meter. The minimum or poor power factor relative to other energy meters record was 0.124035 and its power factor charge was 12,011.58 ETB which is approximately equivalent to 214.11USD. The total power factor charge for only recorded data for four months was 71,537.33ETB (1,275.17USD). The institution is paying unwanted charge that can be improved by using power factor correction capacitor. The reactive power (kVAR) required to correct the power factor to 0.9 have been computed in this paper. The money expended for low power factor will be saved and the system’s power quality increase as well.

Effect of surface composition on the stability of Ti- and V-based oxycarbide and oxynitride MXenes

Oxycarbide MXenes were recently experimentally identified, opening up the possibility of a vast majority of carbon-based MXenes synthesised to date being in fact oxycarbides, wherein some substitutional oxygen atoms are present amid the layers that were previously thought to contain carbon only. Here, using an approach based on density-functional theory, we study the structural, energetic and electronic properties of subsurface substitutional oxygen atoms on the X layers of MXenes of the form M2XT2, with M = Ti, V; X = C, N; and T = none, O or F. According to the calculations, subsurface O is thermodynamically stable in any concentration on all the analysed MXenes.Subsurface substitutional O atoms in the Ti2C MXene are thermodynamically driven towards the surface, leaving behind vacancies and creating local O surface terminations. Given that this process involves a very low energy barrier, we predict that, under conditions suitable for eliminating the surface termination of MXenes, many vacancies on the layers of X atoms should occur.The O-terminated carbide MXenes, Ti2CO2 and V2CO2, are stable with their hexagonal symmetry up to a threshold amount of subsurface O, around 75 %, which is above the maximum experimentally observed concentration, 65 %. The F surface termination stabilizes the hexagonal structure of MXenes, which no longer distort regardless of the presence and amount of subsurface oxygen. This suggests that MXene synthesis routes based on fluorine-containing compounds are the most indicated for synthesising nitride MXenes.The PBE functional predicts the semiconductor characteristics of the Ti2CO2 MXene to be lost in the presence of subsurface O, even a percentage as low as 6 %, the lowest considered in this work. The hybrid HSE06 functional predicts the oxycarbide material to remain a semiconductor, but with a significantly lowered band gap energy with increasing substitutional O content. Nevertheless, both functionals agree that the mixture of C and O atoms between the Ti layers of the Ti2CO2 MXene increases its conductivity. To the best of our knowledge, this MXene has never been confirmed experimentally to behave as a semiconductor probably because the real samples of this MXene contain subsurface oxygen.

Radiation-Induced Hydrogel for Water Treatment.

Along with serving as drug delivery sensors and flexible devices, hydrogels are playing pioneering roles in water purification. Both chemical and radiation methods can produce hydrogels, with the latter method gaining preference for its pure adducts. The water treatment process entails the removal of heavy and toxic metals (above the threshold amount), dyes, and solid wastes from industrial effluents, seawater, and groundwater, as well as sterilization for microorganism destruction. This review analyzed the different types of hydrogels produced by applying various radiations for water treatment. Particularly, we examined the hydrogels created through the application of varying levels of gamma and electron beam radiation from the electron gun and Co-60 sources. Moreover, we discuss the optimized radiation doses, the compositions (monomers and polymers) of raw materials required for hydrogel preparation, and their performance in water purification. We present and predict the current state and future possibilities of radiation-induced hydrogels. We explain and compare the superiority of one radiation method over other radiation methods (UV-visible, X-ray, microwave, etc.) based on water treatment.

Pathophysiology of Diet-Induced Acid Stress.

Diets can influence the body's acid-base status because specific food components yield acids, bases, or neither when metabolized. Animal-sourced foods yield acids and plant-sourced food, particularly fruits and vegetables, generally yield bases when metabolized. Modern diets proportionately contain more animal-sourced than plant-sourced foods, are, thereby, generally net acid-producing, and so constitute an ongoing acid challenge. Acid accumulation severe enough to reduce serum bicarbonate concentration, i.e., manifesting as chronic metabolic acidosis, the most extreme end of the continuum of "acid stress", harms bones and muscles and appears to enhance the progression of chronic kidney disease (CKD). Progressive acid accumulation that does not achieve the threshold amount necessary to cause chronic metabolic acidosis also appears to have deleterious effects. Specifically, identifiable acid retention without reduced serum bicarbonate concentration, which, in this review, we will call "covert acidosis", appears to cause kidney injury and exacerbate CKD progression. Furthermore, the chronic engagement of mechanisms to mitigate the ongoing acid challenge of modern diets also appears to threaten health, including kidney health. This review describes the full continuum of "acid stress" to which modern diets contribute and the mechanisms by which acid stress challenges health. Ongoing research will develop clinically useful tools to identify stages of acid stress earlier than metabolic acidosis and determine if dietary acid reduction lowers or eliminates the threats to health that these diets appear to cause.

Awareness and knowledge of drug decriminalization among people who use drugs in British Columbia: a multi-method pre-implementation study

BackgroundIn January 2023, British Columbia implemented a three-year exemption to Controlled Drugs and Substances Act, as granted by the federal government of Canada, to decriminalize the personal possession of small amounts of certain illegal drugs. This decriminalization policy, the first in Canada, was announced in response to the overdose emergency in British Columbia as a public health intervention that could help curb overdose deaths by reducing the impact of criminalization and increasing access to health and social services through stigma reduction.MethodsThe current multi-method study examines people who use drugs’ awareness and knowledge of British Columbia’s decriminalization model through cross-sectional quantitative surveys and qualitative interviews among people who use drugs from September–November 2022, immediately prior to the implementation of decriminalization.ResultsQuantitative findings show that two-thirds (63%) of people who use drugs were aware of the policy, but substantial knowledge gaps existed about the legal protections afforded (threshold amount, substances included, drug trafficking, confiscation). The qualitative findings suggest that people who use drugs misunderstood the details of the provincial decriminalization model and often conflated it with regulation. Results suggest that information sharing about decriminalization were minimal pre-implementation, highlighting areas for knowledge dissemination about people who use drugs' rights under this policy.ConclusionsGiven that decriminalization in British Columbia is a new and landmark reform, and that the success of decriminalization and its benefits may be undermined by poor awareness and knowledge of it, efforts to share information, increase understanding, and empower the community, may be required to promote its implementation and benefits for the community.

Conjectures of British Investment, Tax Revenues, and Deficit Amounts from the Thirteenth to the Nineteenth Century using the Concept of Economic Surplus

This article attempts to estimate trends in the levels of public and private investment, and national government surpluses and deficits from accumulated capital income, taxation, and rents estimated by different economic historians for England and the UK by utilizing the concept of Paul Baran and Paul Sweezy’s economic surplus. The data support historical accounts that income per capita growth begins to increase around the 1600s in Britain, perhaps due to the level of capital, tax, and land income achieving an adequate threshold amount. According to some historians, this would also be about the time of capitalism’s ascent as the dominant economic system in Britain. Even then, dramatic increases in investment and economic growth do not appear until the late eighteenth century when investment and deficits reach even higher levels. The new estimates developed in this article are offered as additional macroeconomic data supplements to works created by other authors and researchers and submitted as a demonstration of the concept of economic surplus and the power of threshold levels of private and public investment. Most of all they also give some support to Baran and Sweezy’s notion of a society’s economic surplus coming from labor exploitation and being used to further investment and government expenditures.

Education protects against the detrimental effect of hippocampal atrophy on episodic memory decline

AbstractBackgroundHippocampal volume loss and episodic memory decline are early signs of Alzheimer’s disease (AD). Cognitive reserve refers to individual differences that enable people to perform cognitive tasks at a higher level than expected based on their current level of neurodegeneration (Stern et al., 2020).In the current study we test the hypothesis that education, a sociobehavioural proxy of reserve, moderates the association between hippocampal atrophy and memory function in persons at preclinical stages of AD.MethodData from the Quebec Consortium for the early identification of Alzheimer’s disease were used (CIMAQ; Belleville et al., 2019). Sixty two older adults (38 females, 24 males; mean age = 74 years old, SD = 5.4, range = 65‐88; mean education = 15 years, SD = 3.3, range = 7‐22) were diagnosed with subjective cognitive decline (SCD) or mild cognitive impairment (MCI). Anatomical 3D‐T1‐w MRIs were collected at baseline and used to calculate hippocampal volume with FreeSurfer 5.3 (Belleville et al., 2021). A Face‐Name associative memory test was conducted at three time points: baseline, two years later, and four years later. Memory change was measured as the average individual slope (over three time points) of associative memory accuracy (correctly recognizing face‐name pairs). Analyses were conducted with using R (R Core Team, 2020).ResultYears of education significantly moderated the effect of hippocampal volume on memory over time, β = ‐1.97 (SE = 0.93; 95% CI = ‐3.83, ‐0.11), p = .04. Hippocampal volume had a significant negative correlation with memory over time in people with lower education levels (1 SD below the mean), but not for mean levels or higher education levels (1 SD above the mean; Figure 1). A Johnson‐Neyman plot revealed that people with over 14 years of education showed resilience to the negative association of hippocampal volume loss and memory over time, while those with 14 years or below did not (Figure 2).ConclusionEducational attainment contributes to cognitive reserve by buffering against the detrimental effect of hippocampal atrophy on declining associative memory in preclinical AD. The current findings offer practical relevance by showing that 14 years is a threshold amount of education that confers a protective influence against memory decline.

Experimental analysis of development, lipid accumulation and gene expression in a high-latitude marine copepod

Abstract The high-latitude copepod Neocalanus flemingeri exploits the spring phytoplankton bloom to accumulate lipids for survival during food-limited periods and to fuel reproduction. At some point during development, lipid-accumulation ends and pre-adults molt into adults, descend to depth and enter a state of dormancy termed "diapause." How and when they determine to make this transition is still unresolved. According to one hypothesis, the trigger is their attaining a threshold amount of "lipid fullness." Alternatively, they might follow a genetic program, entering diapause within a narrow developmental window. To better understand the decision, a 5-week laboratory experiment was conducted to assess the effect of food quantity and type on lipid accumulation, biomass and gene expression in N. flemingeri copepodite stage CV. In fed individuals, the initial rate of lipid accumulation slowed by week 5, as a portion of CVs began to molt into adults. While changes in gene expression common to all fed individuals between weeks 1 and 3 were consistent with a developmental program, the duration of the CV stage was variable. Unfed individuals maintained lipid stores initially, suggesting physiological acclimatization to conserve energy. A comparison with gene expression profiles of field-collected individuals suggests similar responses to resources in the environment.

Influence of Excess Conjugated Wrapping Polymer in Semiconducting Single-Walled Carbon Nanotube Dispersions

Single-walled carbon nanotubes (SWNTs) are promising nanomaterials for incorporation into organic electronic devices (OEDs), with the potential to fabricate flexible devices while exploiting inexpensive solution-processing techniques. As-synthesized SWNTs are insoluble and comprised of a mixture of metallic and semiconducting SWNTs (sc-SWNTs), necessitating dispersal and purification before integration into OEDs. Refinement of conjugated polymer extraction techniques has allowed for the isolation of sc-SWNTs from metallic in a reproducible and scalable manner. The availability of highly-pure sc-SWNT materials has facilitated the production of thin-film transistors (TFTs) with very high charge carrier mobilities, outperforming organic small molecule and polymer semiconductors. However, the realization of commercial OED applications of polymer-sorted sc-SWNTs have not yet been achieved, partially due to the prohibitive time and materials costs associated with purifying sc-SWNTs.Current protocols for dispersing sc-SWNTs with conjugated polymers involve three broad steps: (1) dispersion of bulk SWNT material, (2) removal of non-dispersed carbonaceous materials, and (3) removal of excess polymer through filtration or centrifugation. The final step of removal of excess polymer is time-consuming and wasteful, but viewed as necessary for preparing high-performing TFTs, as the conjugated polymer has much lower performance compared to SWNTs.In this study we performed the first systematic investigation of the effect of excess polymer on SWNT TFT performance. Three SWNT concentrations were investigated, with varying ratios of excess polymer added to each. TFT device performance was monitored using several metrics, including: mobility, threshold voltage, on/off ratios and hysteresis. Characterization of large numbers of replicate TFT devices determined that below a threshold amount of excess polymer the presence of excess polymer did not have a negative impact on device performance. Detailed analysis of the sc-SWNT films through Raman spectroscopy and atomic force microscopy (AFM) confirmed that a simple rinsing step was sufficient to remove all the unbound conjugated polymer from the substrate surface without affecting the sc-SWNT network. The volume of solvent required for the rinsing step was substantially lower than that required for filtration or centrifugation steps. Furthermore, at higher SWNT concentrations the excess polymer prevented nanotube bundling, resulting in moderate improvements in both mobility and on/off ratios. Our results were reproducible for two different conjugated polymer sc-SWNT systems, demonstrating the versatility of this procedure.

Examining the Presidential Threshold in Law No. 7 of 2017 in terms of legal politics in Indonesia

It was originally proposed that the presidential threshold of 20% be used to support the presidential system. As stated in Article 6A paragraph (2) of the Constitution of the Republic of Indonesia, the constitutional design of the presidential threshold is an additional provision about arrangements on the requirements for the candidacy of the President and Vice President. Because political configuration is so crucial to the creation of legal products, political law presidential threshold policymaking occurs when there is political configuration. What is the history of the presidential threshold policy of 20%? is the first of two problem formulations in this study. Second, how does the presidential threshold of 20% in Law No. 7 of 2017 stand in terms of legal politics? Along with legal and intellectual techniques, the research takes a normative perspective. First, the study's findings show that Indonesia's presidential threshold was first established in Law Number 23 of 2003 concerning the General Election of the President and Vice President. From the 2004 Presidential Election to the 2019 Presidential Election, Indonesia's threshold provisions were the first to be put into practice, with the presidential threshold's amount changing. The legal politics of the presidential threshold have the traits of an authoritarian law, and the legal foundation has changed to Law Number 7 of 2017 concerning the Second General Election. This is so that the ruler can protect his or her political interest in keeping the ruling party in power. Because a presidential threshold with a percentage of up to 20% creates a divide in political rights or democratic rights between parties with majority votes and parties with minority votes, the legal politics of determining the presidential threshold runs counter to the principle of the purpose of an effective and proportional election.

Presenteeism Is Reloaded and Ready for Further Research – A Commentary on Priebe, J. and Hägerbäumer, M. (2023)

Presenteeism Is Reloaded and Ready for Further Research – A Commentary on Priebe, J. and Hägerbäumer, M. (2023)

Detection of the stator inter-turn fault using the energy feature of the wavelet coeffcients obtained through continuous wavelet transform

This research aims to investigate a fault detection method applicable to the stator part of the Brush-Less DC motor (BLDC). Indeed, it is a concern to make sure the motor is operating in a healthy mode, and in any other case, it is of great importance to detect the fault as soon as possible to prevent the further ruin of the major system. Regarding this, a sub-branch method of the Wavelet Transform (WT) analysis, named Continuous Wavelet Transform (CWT), is utilized to observe the short-circuit fault in the stator coils. Thus, a novel simulator of the BLDC motor is developed by making an interconnection between ADAMS and MATLAB in which different electrical and mechanical components are included. Therefore, a close-to-reality model of the BLDC motor is achieved, leading to a more accurate evaluation of the proposed method. An energy-type feature will be suggested to characterize the fault happening. Through acquiring the normalized energy amount for one of the Wavelet Coefficient (WC) signals, obtained by the CWT, and comparing the energy with a predefined threshold amount of energy for that signal, it is feasible to detect the stator's flawed performance. By conducting different simulations, the proposed method will be validated.

An Improved Setting-Free Scheme for Fast and Reliable Detection of Complete and Partial Loss-of-Excitation

In this article, an improved setting-free loss-of-excitation (LOE) protection is developed for fast and reliable classification of various events. In the proposed scheme, the internal voltage and reactive power of the synchronous generator (SG) have been exploited to fulfill the condition of not needing the threshold amount because they are directly dependent on the rotor field and continuously reduced during the LOE, leading to having a negative polarity of variation. However, due to slow dynamic variation during the LOE condition, they are multiplied to accelerate and highlight the reduction changes, giving rise to increasing the detection speed. Meanwhile, owing to the considerable difference between the value of internal voltage and reactive power and to highlight the effect of multiplication function, an adaptive gain on the basis of steady-state parameters of SG is suggested. Furthermore, given that the negative polarity of the multiplied parameters can be affected during the hybrid events, the limited integral function is implemented to eliminate the happened swings, resulting in keeping the negative polarity and thus clustering the hybrid events reliably. The performed simulations on the IEEE 9-bus and 39-bus test systems prove that the provided setting-free protection can detect all types of the events reliably and quickly than other schemes.

A unified theory of discrete and continuous responding.

Understanding the cognitive processes underlying choice requires theories that can disentangle the representation of stimuli from the processes that map these representations onto observed responses. We develop a dynamic theory of how stimuli are mapped onto discrete (choice) and onto continuous response scales. It proposes that the mapping from a stimulus to an internal representation and then to an evidence accumulation process is accomplished using multiple reference points or "anchors." Evidence is accumulated until a threshold amount for a particular response is obtained, with the relative balance of support for each anchor at that time determining the response. We tested this multiple anchored accumulation theory (MAAT) using the results of two experiments requiring discrete or continuous responses to line length and color stimuli. We manipulated the number of options for discrete responses, the number of different stimuli, and the similarity among them, and compared the outcomes to continuous response conditions. We show that MAAT accounts for several key phenomena: more accurate, faster, and more skewed distributions of responses near the ends of a response scale; lower accuracy and slower responses as the number of discrete choice options increases; and longer response times and lower accuracy when alternative responses are more similar to the target response. Our empirical and modeling results suggest that discrete and continuous response tasks can share a common evidence representation, and that the decision process is sensitive to the perceived similarity among the response options. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Selective Hydroxylation of Carbon Fiber Paper for Long‐Lasting Hydrophilicity by a Green Chemistry Process (Adv. Mater. Interfaces 2/2023)

Hydrophilic Carbon Fiber Paper n article number 2201684, Astrid M. Müller and colleagues made initially hydrophobic carbon fiber paper hydrophilic for more than one year, without degrading the material's mesostructure or flexural strength. The rapid aqueous green chemistry process selectively generates surface hydroxyls bound to graphitic edge sites that preserve a threshold amount of adsorbed water. [Artwork by Rachel Heberling and Astrid M. Müller]

Enterotoxic potential of dietary cholesterol autoxidation products

Background In both Western and Westernized diets, together with a relatively high amount of cholesterol, variable amountsof its oxidized metabolites, oxysterols, are consistently consumed. These oxysterols, mostly of non-enzymatic origin, are produced during sterol autoxidation in foodstuff manufacturing and storage. Objective This study aimed to analyze the potential enterotoxic effects of all main oxysterols of non-enzymatic origin so far identified in a variety of foods. Experimental plan Differentiated human intestinal cell monolayers (CaCo-2) were incubated up to 48 h in the presence or absence of 0.5, 1 or 5 µM with one out of seven non-enzymatic oxysterols, prior to the verification of minimal irreversible cell damage within the chosen concentration range. Results All tested oxysterols were proven to exert damaging effects on cell monolayers in vitro. The inflammatory interleukin-8 and monocyte chemotactic protein-1 were mostly upregulated by 7-ketocholesterol and 7β-hydroxycholesterol, respectively, then to a lower extent by 5α,6α-epoxycholesterol, 7α-hydroxycholesterol and 5β,6β-epoxycholesterol. 7-Ketocholesterol and 7β-hydroxycholesterol also appeared to be most effective in impairing claudin-1, occludin and E-cadherin proteins, followed by 25-hydroxycholesterol and triol. Conclusions The oxysterols consistently derived by food autoxidation were tested; they potentially impaired the integrity of the intestinal epithelial barrier and triggered an inflammatory response within 0.5–5 µM concentrations, easily reachable in a single Western meal. Significance Statement This comprehensive analysis focused on the potential impairment of the intestinal barrier by the main dietary non-enzymatic oxysterols, should guide further nutrition research aiming at defining a threshold amount of these cholesterol derivatives in order not to derange the physiological gut–brain axis.

Butanediammonium Salt Additives for Increasing Functional and Operando Stability of Light-Harvesting Materials in Perovskite Solar Cells.

Organic diammonium cations are a promising component of both layered (2D) and conventional (3D) hybrid halide perovskites in terms of increasing the stability of perovskite solar cells (PSCs). We investigated the crystallization ability of phase-pure 2D perovskites based on 1,4-butanediammonium iodide (BDAI2) with the layer thicknesses n = 1, 2, 3 and, for the first time, revealed the presence of a persistent barrier to obtain BDA-based layered compounds with n > 1. Secondly, we introduced BDAI2 salt into 3D lead-iodide perovskites with different cation compositions and discovered a threshold-like nonmonotonic dependence of the perovskite microstructure, optoelectronic properties, and device performance on the amount of diammonium additive. The value of the threshold amount of BDAI2 was found to be ≤1%, below which bulk passivation plays the positive effect on charge carrier lifetimes, fraction of radiative recombination, and PSCs power conversion efficiencies (PCE). In contrast, the presence of any amount of diammonium salt leads to the sufficient enhancement of the photothermal stability of perovskite materials and devices, compared to the reference samples. The performance of all the passivated devices remained within the range of 50 to 80% of the initial PCE after 400 h of continuous 1 sun irradiation with a stabilized temperature of 65 °C, while the performance of the control devices deteriorated after 170 h of the experiment.

Selective Hydroxylation of Carbon Fiber Paper for Long‐Lasting Hydrophilicity by a Green Chemistry Process

AbstractThis study reports the selective hydroxylation of macroscopic carbon surfaces that renders initially hydrophobic carbon fiber paper hydrophilic for more than one year (62 weeks) so far. This long time of sustained hydrophilicity is unprecedented and transforms the utility of macroscopic carbon materials. Quantification of surface oxygenates of a systematic series of 13 chemical treatments reveals that surface hydroxyls are predictors of long‐lasting hydrophilicity. The rapid, mild, acid‐free, transition‐metal‐free treatment does not leave surface residues, inhibits overoxidation of graphitic carbon beyond hydroxyls, and introduces the highest edge density on carbon surfaces, without altering the mesostructure of carbon fiber network architectures and without lowering the flexural strength of carbon fiber paper. Graphitic edges are required for enhanced stability of surface oxygenates that retain a threshold amount of adsorbed water, which is necessary for keeping carbon fiber paper hydrophilic. Application of hydrophilic carbon fiber paper as high‐surface‐area working electrode supports for alkaline water oxidation catalyzed by [NiFe]‐layered double hydroxide nanosheets demonstrates a factor of 60 higher mass activity compared to catalysis on flat basal‐plane highly ordered pyrolytic graphite electrodes.

Nutrient availability as an arbiter of cell size.

Pioneering work carried out over 60 years ago discovered that bacterial cell size is proportional to the growth rate set by nutrient availability. This relationship is traditionally referred to as the 'growth law'. Subsequent studies revealed the growth law to hold across all orders of life, a remarkable degree of conservation. However, recent work suggests the relationship between growth rate, nutrients, and cell size is far more complicated and less deterministic than originally thought. Focusing on bacteria and yeast, here we review efforts to understand the molecular mechanisms underlying the relationship between growth rate and cell size.