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Objective: The aim of this study was to determine the plasma pharmacokinetics of oxytetracycline (OTC) in rainbow trout (Oncorhynchus mykiss) of different body sizes. Methods: The research was carried out on three groups as small (30-50 g), medium (90-110 g) and large (185-215 g) body sizes at 8 ± 0.5 °C. OTC was administered orally at a dose of 60 mg/kg to all groups. Blood samples were taken at 19 different sampling times until the 384 h after oxytetracycline administration. The plasma concentrations of OTC were measured using high pressure liquid chromatography-ultraviolet and pharmacokinetic parameters were evaluated using non-compartmental analysis. Results: OTC was detected in small-body sized fish until the 336 h and in medium and large-body sized fish until the 384 h. The elimination half-life of OTC was 85.46, 87.24 and 86.98 h in the small, medium and large body size groups, respectively. The peak plasma concentration increased from 0.66 to 1.11 µg/mL, and the area under the plasma concentration-versus time curve from zero (0) h to infinity (∞) increased from 87.86 to 151.52 h*µg/mL, in tandem with the increase in fish body size. As fish body size increased, volume of distribution and total body clearance decreased. Conclusion: These results show that the pharmacokinetics of OTC vary depending on fish size. Therefore, there is a need to reveal the pharmacodynamic activity of OTC in rainbow trout of different body sizes.

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Background: Despite its significant usefulness in adolescent health studies, the single-item "body size perception" question, developed within the Health Behaviour in School-aged Children (HBSC) survey, has yet to undergo multidimensional validation. Objectives: To assess the convergent, divergent and concurrent validity of the HBSC body size perception question among adolescents. Methods: The single-item HBSC body size perception question is as follows: "Do you think your body is…?," with answers ranging from "much too thin" to "much too fat." Fifteen-year-old participants included in the analysis were 72,086 from 45 HBSC countries in 2017/18 (concurrent validity), and 595, 127, and 615 in 2021/22 in French-speaking Belgium, Ireland, and Poland, respectively. The convergent, divergent, and concurrent validity was assessed with body dissatisfaction, social desirability, and selfesteem, respectively. The concurrent validity was also examined with body mass index (BMI) from the 2017/18 HBSC data. All analyses were sex-stratified. Results: Cohen's Kappa values were 0.67 [confidence interval (CI): 95%: 0.62, 0.72] and 0.64 (0.59, 0.69) for boys and girls, respectively, in all 3 countries together. Body size perception was associated with social desirability, selfesteem, and BMI, with a stronger association in girls than that in boys. For instance, girls with higher social desirability were less likely to perceive themselves as "too thin" [Relative Risk Ratio (RRR) = 0.78 (0.69, 0.89)] rather than as the "right size." Boys with higher selfesteem were less likely to perceive themselves as "too fat" [0.93 (0.90, 0.97)] rather than the "right size." Girls with underweight were less likely to perceive themselves as "too fat" [0.38 (0.34, 043)] rather than "right size" and girls with overweight/obesity were more likely to perceive themselves as such [8.19 (7.49, 8.95)]. Conclusions: The single-item HBSC body size perception question demonstrated good convergent, divergent, and concurrent validity. It reflects adolescents' own perception of body size, possibly influenced by societal norms and ideals.

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The caloric content and macronutrient ratio of diet consumed is a major source of phenotypic variation in most animal populations. While these nutritional effects have been well-documented for a variety of life-history and morphological traits, the effects of nutrition on male genitals are poorly understood but genitals are thought to be more canalised than general morphology and hence less susceptible to variation in nutrition. Even less is known about the effects of nutrition on female genital form, which to our knowledge, have never been investigated. Here we tested for effects of juvenile dietary macronutrients (protein and carbohydrate) on larval survival, adult morphology, including genital size and shape in male and female flour beetles (Tribolium castaneum). We found there was nutritionally induced plasticity in larval survival and morphology, although the latter effect was variable, with body size being most responsive to dietary macronutrients and genital size and shape being least responsive. Functionally equivalent morphological traits in the sexes responded similarly to nutrition. Previously, we showed that the genitalia of male and female T. castaneum are subject to strong stabilizing sexual selection, and our current findings suggest that developmental mechanisms reduce the nutritional sensitivity of male and female genitals, possibly to ensure matching during mating.

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Discordance between mitochondrial and nuclear DNA is common among animals and can be the result of a number of evolutionary processes, including incomplete lineage sorting and introgression. Particularly relevant in contact zones, mitonuclear discordance is expected because the mitochondrial genome is haploid and primarily uniparentally inherited, whereas nuclear loci are evolving at slower rates. In addition, when closely related taxa come together in hybrid zones, the distribution of diagnostic phenotypic characters and their concordance with the mitochondrial or nuclear lineages can also inform on historical and ongoing dynamics within hybrid zones. Overall, genetic and phenotypic discordances provide evidence for evolutionary divergence and processes that maintain boundaries among sister species or lineages. In this study, we characterized patterns of genetic and phenotypic variation in a contact zone between Cycloramphus dubius and Cycloramphus boraceiensis, two sister species of frogs endemic to the Atlantic Coastal Forest of Brazil. We examined genomic-scale nuclear diversification across 19 populations, encompassing the two parental forms and a contact zone between them. We compared the distribution of genomic DNA variability with that of a mitochondrial locus (16S) and two morphological traits (dorsal tubercles and body size). Our results reveal multiple divergent lineages with ongoing admixture. We detected discordance in patterns of introgression across the three data types. Cycloramphus dubius males are significantly larger than C. boraceiensis males, and we posit that competition among males in the hybrid zone, coupled with mate choice by females, may be one mechanism leading to patterns of introgression observed between the species.

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The common non-contact, automatic body size measurement methods based on the whole livestock point cloud are complex and prone to errors. Therefore, a cattle body measuring system is proposed. The system includes a new algorithm called dynamic unbalanced octree grouping (DUOS), based on PointNet++, and an efficient method of body size measurement based on segmentation results. This system is suitable for livestock body feature sampling. The network divides the cow into seven parts, including the body and legs. Moreover, the key points of body size are located in the different parts. It combines density measurement, point cloud slicing, contour extraction, point cloud repair, etc. A total of 137 items of cattle data are collected. Compared with some of the other models, the DUOS algorithm improves the accuracy of the segmentation task and mean intersection by 0.53% and 1.21%, respectively. Moreover, compared with the manual measurement results, the relative errors of the experimental measurement results are as follows: withers height, 1.18%; hip height, 1.34%; body length, 2.52%; thoracic circumference, 2.12%; abdominal circumference, 2.26%; and cannon circumference, 2.78%. In summary, the model is proven to have a good segmentation effect on cattle bodies and is suitable for cattle body size measurement.

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Animals exhibiting mirror self-recognition (MSR) are considered self-aware; however, studies on their level of self-awareness remain inconclusive. Recent research has indicated the potential for cleaner fish (Labroides dimidiatus) to possess a sophisticated level of private self-awareness. However, as this study revealed only an aspect of private self-awareness, further investigation into other elements is essential to substantiate this hypothesis. Here, we show that cleaner fish, having attained MSR, construct a mental image of their bodies by investigating their ability to recall body size. A size-based hierarchy governs the outcomes of their confrontations. The mirror-naïve fish behaved aggressively when presented with photographs of two unfamiliar conspecifics that were 10% larger and 10% smaller than their body sizes. After passing the MSR test, they refrained from aggression toward the larger photographs but still behaved aggressively toward the smaller ones without re-examining their mirror images. These findings suggest that cleaner fish accurately recognize their body size based on mental images of their bodies formed through MSR. Additionally, mirror-experienced fish frequently revisited the mirror when presented with an intimidating larger photograph, implying the potential use of mirrors for assessing body size. Our study established cleaner fish as the first non-human animal to be demonstrated to possess private self-awareness.

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The variance-mean scaling in population abundance or Taylor's power law (TPL) has been reported hundreds of times and is related to ecological processes such as competition, dispersal or territoriality. In this sense, the TPL was extensively validated to resume population variability and to show the action of ecological mechanisms. Baumgartner and Peláez (2024) combine databases of fish dynamics along the United States, species traits, species phylogeny and climatic conditions, estimating the TPL for 180 species along 972 populations. The observed scaling suggests that the variability of the population decreases with abundance. Notably, 68% of the variation in the variance-mean scaling was explained by species traits and environmental conditions. Specifically, the life history of the species, associated with its body size, was the main explanation for the TPL, also reporting that the variability of the population increased faster with mean abundance in the headwaters than in other river sections. Equally important, the diversity of the community in which the species were inserted did not affect the scaling. These results provide overwhelming evidence on the nature of TPL on large geographic scales and how they are affected by species biology and environmental conditions. A contribution that should motivate further empirical and theoretical analysis of the TPL and its determinants.

El escalamiento en varianza con la media de la abundancia poblacional, ha sido reportado en cientos de sistemas y es conocido como Ley Poder de Taylor (TPL, de sus siglas en inglés). Este escalamiento se ha relacionado con la importancia de la competencia, dispersión o territorialidad, resumiendo la dinámica poblacional y su conexión con distintos mecanismos ecológicos. El estudio publicado por Baumgartner y Peláez (2024) combina bases de datos de dinámica de peces en los Estados Unidos de América, de sus rasgos, filogenia y ambientales, estimando la TPL para un total de 180 especies a lo largo de 972 poblaciones. El escalamiento observado sugiere que la variabilidad disminuye con la abundancia de las poblaciones. Notablemente, el 68% de la variación en el escalamiento fue explicado por los rasgos de las especies (historia de vida y tamaño corporal) y las condiciones ambientales. Aumentando más rápidamente la variabilidad en la dinámica poblacional con la abundancia media en las cabeceras que en otras secciones del río. Igualmente importante fue la falta de efectos significativos de la biodiversidad de la comunidad sobre el escalamiento varianza­media de sus poblaciones. Estos resultados proporcionan una contundente evidencia sobre la naturaleza de la TPL en grandes escalas geográficas y cómo se ve afectada por la biología de las especies y las condiciones ambientales. Resultados y abordajes que sugieren futuros análisis empíricos y teóricos sobre la TPL y sus determinantes.

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Squamate reptiles are central for studying phenotypic correlates of evolutionary transitions from oviparity to viviparity because these transitions are numerous, with many of them being recent. Several models of life-history theory predict that viviparity is associated with increased female size, and thus more female-biased sexual size dimorphism (SSD). Yet, the corresponding empirical evidence is overall weak and inconsistent. The lizard Zootoca vivipara, which occupies a major part of Northern Eurasia and includes four viviparous and two non-sister oviparous lineages, represents an excellent model for testing these predictions. We analysed how sex-specific body size and SSD is associated with parity mode, using body length data for nearly 14,000 adult individuals from 97 geographically distinct populations, which cover almost the entire species' range and represent all six lineages. Our analyses controlled for lineage identity, climatic seasonality (the strongest predictor of geographic body size variation in previous studies of this species) and several aspects of data heterogeneity. Parity mode, lineage and seasonality are significantly associated with female size and SSD; the first two predictors accounted for 14%-26% of the total variation each, while seasonality explained 5%-7%. Viviparous populations exhibited a larger female size than oviparous populations, with no concomitant differences in male size. The variation of male size was overall low and poorly explained by our predictors. Albeit fully expected from theory, the strong female bias of the body size differences between oviparous and viviparous populations found in Z. vivipara is not evident from available data on three other lizard systems of closely related lineages differing in parity mode. We confront this pattern with the data on female reproductive traits in the considered systems and the frequencies of evolutionary changes of parity mode in the corresponding lizard families and speculate why the life-history correlates of live-bearing in Z. vivipara are distinct. Comparing conspecific populations, our study provides the most direct evidence for the predicted effect of parity mode on adult body size but also demonstrates that the revealed pattern may not be general. This might explain why across squamates, viviparity is only weakly associated with larger size.

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Anthropogenic climate change has increased the frequency and intensity of marine heatwaves that may broadly impact the health of marine invertebrates. Rising ocean temperatures lead to increases in disease prevalence in marine organisms; it is therefore critical to understand how marine heatwaves impact immune system development. The purple sea urchin (Strongylocentrotus purpuratus) is an ecologically important, broadcast-spawning, omnivore that primarily inhabits kelp forests in the northeastern Pacific Ocean. The S. purpuratus life cycle includes a relatively long-lived (∼2 months) planktotrophic larval stage. Larvae have a well-characterized cellular immune system that is mediated, in part, by a subset of mesenchymal cells known as pigment cells. To assess the role of environmental temperature on the development of larval immune cells, embryos were generated from adult sea urchins conditioned at 14 °C. Embryos were then cultured in either ambient (14 °C) or elevated (18 °C) seawater. Results indicate that larvae raised in an elevated temperature were slightly larger and had more pigment cells than those raised at ambient temperature. Further, the larval phenotypes varied significantly among genetic crosses, which highlights the importance of genotype in structuring how the immune system develops in the context of the environment. Overall, these results indicate that larvae are phenotypically plastic in modulating their immune cells and body length in response to adverse developmental conditions.

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Despite the range of body sizes in children, few ventricular assist devices (VAD) exist to support pediatric patients with end-stage heart failure. Large registry data identified weight < 20 kg to be associated with higher rates of VAD-related stroke, compared to > 40 kg. Moreover, patients < 1 years of age experience the highest post-implant mortality, with 1-year survival improving in an age-dependent manner. Within different VAD types, intracorporeal continuous (IC) devices confer the greatest clinical benefit and quality of life compared to paracorporeal alternatives. The major limitation of IC VADs is the technical challenge of implantation into patients of small body size, thus the majority of patients with IC devices are pre-adolescents or older. However, since 2021, the use of HeartMate 3™ (HM3) has expanded to patients as small as 17.7 kg. Although HM3 offers equally favorable survival outcomes irrespective of body size, patients of low body surface area are more likely to experience non-device-related major infections and renal dysfunction, with suggestion for elevated risk of major bleeding and stroke. Innovative imaging strategies have emerged to assess the feasibility of HM3 implantation and facilitate preoperative planning in small children. Moreover, the unmet need for an IC device in the infant population has revived interest in the axial pump, with a pivotal clinical trial currently underway. VAD outcomes in the pediatric population are not equivalent across all ages and body sizes, thus size-stratified analyses and device development to serve the full spectrum of body habitus are key considerations as this field rapidly evolves.

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Objective: The aim of this study was to assess temporal changes in physical fitness of Chinese adolescents aged 13-18 years from 1985 to 2019. Methods: Body size /composition and physical fitness indicators, including body height, weight, body mass index (BMI), speed, power, flexibility, muscular endurance, and cardiorespiratory fitness (CRF), were selected from Chinese boys and girls aged 13-18 years from eight Chinese National Surveillance on Students' Constitution and Health from 1985 to 2019. Temporal changes in means were estimated by sample-weighted linear regression at the test × sex × age level, and national trends were estimated by a post-stratification population weighting procedure. Results: Overall mean body height, weight and BMI increased significantly for Chinese adolescents over 34 years. There was a small improvement for boys in speed (Effect size [ES] = -0.21, 95% confidence interval [CI] = -0.44 ~ 0.02), a small improvement for boys in power (ES = 0.24, 95% CI = -0.20 ~ 0.69), a small improvement for girls in flexibility (ES = 0.45, 95% CI = 0.15 ~ 0.76), a moderate decline for boys (ES = -0.53 95% CI = -0.84 ~ -0.21) and a moderate improvement for girls (ES = 0.61, 95% CI = -0.03 ~ 1.26) in muscular endurance, and large declines in cardiorespiratory fitness (CRF) for boys (ES = 0.93, 95% CI = 0.64 ~ 1.21) and girls (ES = 0.93, 95% CI = 0.58 ~ 1.27) from 1985 to 2019. These trends in each component of fitness were more positive for adolescents aged 13-15 years than that of adolescents aged 16-18 years in both sexes, except for girls in flexibility. Conclusion: The decline in CRF was most pronounced among Chinese children and adolescents from 1985 to 2019, suggesting a future decline in population health that needs attention.

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Across the tree of life, species have repeatedly evolved similar phenotypes. While well-studied for ecological traits, there is also evidence for recurrent evolution of sexually selected traits. Swordtail fish (Xiphophorus) are a classic model system for studying sexual selection, and female Xiphophorus exhibit strong mate preferences for large male body size and a range of sexually dimorphic ornaments. Interestingly, sexually selected traits have also been lost multiple times in the genus. However, there has been uncertainty over the number of losses of ornamentation and large body size because phylogenetic relationships between species in this group have historically been controversial, partially due to prevalent gene flow. Here, we use whole-genome sequencing approaches to re-examine phylogenetic relationships within a Xiphophorus clade that varies in the presence and absence of sexually selected traits. Using wild-caught individuals, we determine the phylogenetic placement of a small, unornamented species, X. continens, confirming an additional loss of ornamentation and large body size in the clade. With these revised phylogenetic relationships, we analyze evidence for coevolution between body size and other sexually selected traits using phylogenetic comparative methods. These results provide insights into the evolutionary pressures driving the recurrent loss of suites of sexually selected traits.

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Purpose: Body image affects health practices. With acculturation superimposed on globalization, 21st century body size preferences of African immigrants, one of the fasting growing populations in the United States, are unknown. Therefore, in African immigrants living in America we assessed: 1) body size preference; and 2) body size dissatisfaction. Methods: Participants chose two silhouettes from the Stunkard Figure Rating Scale: one for body size preference and one for perceived body size. Each silhouette corresponds to a BMI category: (a) Underweight: 1 and 2; (b) Normal weight: 3 and 4; (c) Overweight: 5, 6 and 7; (d) Obesity: 8 and 9. Dissatisfaction was defined as the difference between silhouette numbers for perceived and preferred body size. Results: Characteristics of the 412 participants were: women: 42% (174/412), age 40±11y (mean±SD), range 20-69 y, BMI 27.9±4.6, range 19.5-47.3 kg/m2. As a body size of preference, no one (0/412) chose obese silhouettes. Normal weight silhouettes were chosen as their body size of preference by 75% (131/174) of women and 60% (143/238) of men. Overweight silhouettes were chosen as their preferred body size by 11% (19/174) of women and 26% (62/238) of men. Combining normal and overweight silhouettes into one group, 86% (150/174) of women and 86% (205/238) of men preferred to be either normal or overweight. Underweight silhouettes were preferred by 14% (24/174) of women and 14% (33/238) of men. Dissatisfaction because body size was too large occurred in 78% (135/174) of women and 53% (126/238) of men. Dissatisfaction because body size was too small occurred in 6% (11/174) of women and 16% (38/238) of men. Conclusion: African immigrants prefer body sizes which are normal or overweight. However, and presumably attributable to the combined influence of globalization and acculturation, a worrisome fraction of African immigrants favor an underweight silhouette.

Understanding the attitudes of Africans towards body size is important because these attitudes affect health behaviors. The 20th century consensus was that Africans viewed large body sizes as a sign of the health, beauty, fertility, and prosperity. In addition, underweight silhouettes were viewed with fear and considered to be a sign of poverty, malnutrition, and HIV infection. In the 21st century, African attitudes towards body size are unknown. African immigrants are a rapidly growing segment of the American population. Their attitudes toward body size are influenced by both globalization and acculturation. In our cohort, we found 86% of the Africans living in America wanted to be either normal or low range overweight. However, and very concerning, 14% of African immigrants chose underweight silhouettes to represent their body size of preference. As weight loss programs are brought forward in and by African communities living in the United States, the emphasis must be on achieving a healthy weight and not glorification of underweight silhouettes.

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Most ecological studies attempting to understand causes of population dynamics and community structure disregard intraspecific trait variation. We quantified the importance of natural intra-cohort variation in body size and density of juveniles for recruitment of a sessile marine organism, the barnacle Semibalanus balanoides. Barnacles are representative of species organised in metapopulations, that is, as open local populations connected by larval dispersal. We tracked the individual growth and survival of a cohort of juvenile barnacles from two shores of North Wales. Barnacles settled as larvae in spring of 2002 on previously cleared rock. The density of these new recruits was experimentally manipulated in June and randomly selected individuals were monitored from June to October to evaluate the role of barnacle size and density in predicting survival. In doing so we characterised density at three spatial scales (quadrat: 25 cm2, cells within quadrats: 25 mm2 and neighbourhood: number of neighbours in physical contact with the target barnacle). At all scales, variations in juvenile body size exacerbated the effect of density-dependent mortality on population size. While density-dependent mortality was very intense in the small-sized individuals, large-sized individuals experienced very weak density-dependent mortality and showed high survival rates. Using the concept of 'Jensen inequality', we show that important biases in estimations of survival, based on population size only, occur at high barnacle densities, where survival is low. Our study highlights the role of body size variation in understanding dynamics of open populations.

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Both the metabolic theory of ecology and dynamic energy budget theory predict that climate influences body size through its effects on first-order determinants of energetics: reactive temperatures, carbon resources and oxygen availability. Although oxygen is seldom limiting in terrestrial systems, temperature and resources vary spatially. We used redundancy analyses and variation partitioning to evaluate the influence of climatic temperature, precipitation and their seasonalities on multivariate body size across the distributions of four species of the western rattlesnake group in North America (Crotalus pyrrhus, C. scutulatus, C. oreganus and C. viridis). Most species showed a pattern of increased body size in cooler, mesic climates and decreased body size in warmer, xeric climates. Exceptions to the pattern provided additional context through climatic idiosyncrasies in the distributions of each species. For example, the general pattern of a negative influence of temperature on body size was not apparent for C. oreganus, which ranges across the mildest climates overall among the four species. In contrast to previous studies, we found that seasonality had negligible effects on body size. We suggest that precipitation gradients correlate positively with resource availability in driving intraspecific body size and that temperature compounds this gradient by increasing baseline metabolic demands and restricting activity in particularly warm or otherwise extreme climates.

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Broaching issues of identity and power with clients in the context of their mental health care is affirmed as an effective multicultural and social justice counseling skill by a growing evidence base. Considerations for broaching body size, including size difference and sizeism, with clients has not yet been studied, thus clinicians lack guidelines for facilitating these conversations. In this consensual qualitative research study, we present themes involved in broaching body topics based on our interviews with nine clinicians specialized in treating clients with eating disorders and body-related counseling concerns. Themes addressed counselor development, conceptualization of broaching, clinical-decision-making, practice, and impact of broaching body topics in session. Clinicians identified professional and personal developments they pursued and would advocate for training future clinicians to better serve clients. Descriptions of unique and shared aspects of broaching clients' intersectionality and body-size specifically depict avenues for tailoring broaching conversations. Specific examples of effective and ineffective broaching conversations, including language used and psychoeducational components, provide recommendations for practice and connect to observed impacts on the client, counselor, and counseling process.

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INTRODUCTION: Contrast Enhanced Computed Tomography (CECT) abdomen and pelvis is a common imaging procedure. Hospitals typically follow fixed protocols of contrast volume administration for triple-phase CECT abdomen and pelvis scans and have found that patients are either underdosed or overdosed with respect to their body habitus. The aim of the study was to correlate different patient characteristics such as Total body weight (TBW), Lean Body Mass (LBM), Body Mass Index (BMI), Body Surface Area (BSA) and Blood Volume (BV) with aortic enhancement in the arterial and portal venous phases for CECT Abdomen and pelvis. METHODS: A total of 106 patients who underwent triple-phase CECT abdomen & pelvis were retrospectively studied. A circular region-of-interest (ROI) of 100 mm2 was positioned on descending aorta for unenhanced, arterial, and portal venous phases to measure the aortic enhancement in Hounsfield's units. Measure of contrast attenuation (ΔH) was calculated from the difference of CT values on unenhanced images and contrast images. Correlation analysis was performed to evaluate the relation of patient body characteristics with aortic enhancement. RESULTS: Correlation analysis revealed that BMI exhibited the least correlation when compared to the other characteristics in both arterial (r = -0.3; p = 0.002) and portovenous phases (r = -0.35; p < 0.001) whereas TBW, LBW, BSA and BV reported moderate inverse correlations. BV was found to be the strongest of all characteristics under linear regression. CONCLUSION: The study supports the use of protocols that adjust contrast volume to either TBW, LBW, BSA, or BV for CT abdomen and pelvis scan. IMPLICATION OF PRACTICE: The right body parameter ensures optimal contrast enhancement, improving the visualization of anatomical structures and helps in adapting tailored contrast injection protocols.

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Body size reduction is a universal response to warming, but its ecological consequences across biological levels, from individuals to ecosystems, remain poorly understood. Most biological processes scale with body size, and warming-induced changes in body size can therefore have important ecological consequences. To understand these consequences, we propose a unifying, hierarchical framework for the ecological impacts of intraspecific body size reductions due to thermal plasticity that explicitly builds on three key pathways: morphological constraints, bioenergetic constraints and surface-to-volume ratio. Using this framework, we synthesize key consequences of warming-induced body size reductions at multiple levels of biological organization. We outline how this trait-based framework can improve our understanding, detection and generalization of the ecological impacts of warming.

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In many animal species, larger body size is positively correlated with male mating success and female fecundity. However, in the case of insects, in high seasonality environments, natural selection favors a faster maturation that decreases the risk of pre-reproductive death. However, this advantageous adaptation comes at a tradeoff, resulting in a reduction in body size. Maturation time is influenced by environmental factors, such as temperature, season length, and food availability during the rains. The geographic variation in these parameters provides an opportunity to study their impact on the adaptive evolution of body size in Pyrgomorphidae grasshoppers. These grasshoppers exhibit remarkable variation in body size and wing development and can be found in diverse plant communities across Africa, Asia, Australia, and tropical America. In this study, we utilized a phylogenetic approach to examine the evolution of body size, considering climatic factors, and the influence of sexual selection on size differences between males and females. We found a positive correlation between mean annual temperature and sexual size dimorphism (SSD). Remarkably, species exhibiting a strong bias toward larger females were found to be adapted to regions with higher temperatures. In the Pyrgomorphidae family, an intermediate body size was identified as the ancestral trait. Additionally, winged male and female grasshoppers were observed to be larger than their wingless counterparts. Despite the potential conflicting pressures on body size in males and females, these grasshoppers adhere to Rench's Rule, suggesting that sexual selection on males' body size may explain the evolution of SSD.

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PREMISE: Whole-genome duplication (WGD, polyploidization) has been identified as a driver of genetic and phenotypic novelty, having pervasive consequences for the evolution of lineages. While polyploids are widespread, especially among plants, the long-term establishment of polyploids is exceedingly rare. Genome doubling commonly results in increased cell sizes and metabolic expenses, which may be sufficient to modulate polyploid establishment in environments where their diploid ancestors thrive. METHODS: We developed a mechanistic simulation model of photosynthetic individuals to test whether changes in size and metabolic efficiency allow autopolyploids to coexist with, or even invade, ancestral diploid populations. Central to the model is metabolic efficiency, which determines how energy obtained from size-dependent photosynthetic production is allocated to basal metabolism as opposed to somatic and reproductive growth. We expected neopolyploids to establish successfully if they have equal or higher metabolic efficiency as diploids or to adapt their life history to offset metabolic inefficiency. RESULTS: Polyploid invasion was observed across a wide range of metabolic efficiency differences between polyploids and diploids. Polyploids became established in diploid populations even when they had a lower metabolic efficiency, which was facilitated by recurrent formation. Competition for nutrients is a major driver of population dynamics in this model. Perenniality did not qualitatively affect the relative metabolic efficiency from which tetraploids tended to establish. CONCLUSIONS: Feedback between size-dependent metabolism and energy allocation generated size and age differences between plants with different ploidies. We demonstrated that even small changes in metabolic efficiency are sufficient for the establishment of polyploids.

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