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The amazing morphological diversity of phytoplankton has to be considered an evolutionarily driven compendium of strategies to cope with the strong variability and unpredictability of the pelagic environment. Phytoplankton collects unicellular and colonial photosynthetic organisms adapted to live in apparent suspension in turbulent water masses. Turbulence represents a key driver of phytoplankton dynamics in all aquatic ecosystems and phytoplankton morphological variability is the evolutionary response of this group of photosynthetic organisms to the temporal and spatial scales of variability of turbulence. This paper reviews the existing literature on the effects exerted by turbulence on phytoplankton populations and is aimed at showing how deeply turbulence contributes to the shape and size structure of phytoplankton assemblages. Our aim is to explore how turbulence governs phytoplankton access to resources and, at the same time, how the shape and size structure of phytoplankton represent the evolutionary way in which this group of organisms has optimised its survival in the highly dynamic aquatic environment. The paper is intended to serve as an homage to the (phytoplankton) ecologist Colin S. Reynolds. His life-long work highlighted how profoundly the ecology of phytoplankton depends on the physical constraints governing the movements of the water masses in which phytoplankton evolved and lives.

Finite element head (FE) models are important numerical tools to study head injuries and develop protection systems. The generation of anatomically accurate and subject-specific head models with conforming hexahedral meshes remains a significant challenge. The focus of this study is to present two developmental works: first, an anatomically detailed FE head model with conforming hexahedral meshes that has smooth interfaces between the brain and the cerebrospinal fluid, embedded with white matter (WM) fiber tracts; second, a morphing approach for subject-specific head model generation via a new hierarchical image registration pipeline integrating Demons and Dramms deformable registration algorithms. The performance of the head model is evaluated by comparing model predictions with experimental data of brain–skull relative motion, brain strain, and intracranial pressure. To demonstrate the applicability of the head model and the pipeline, six subject-specific head models of largely varying intracranial volume and shape are generated, incorporated with subject-specific WM fiber tracts. DICE similarity coefficients for cranial, brain mask, local brain regions, and lateral ventricles are calculated to evaluate personalization accuracy, demonstrating the efficiency of the pipeline in generating detailed subject-specific head models achieving satisfactory element quality without further mesh repairing. The six head models are then subjected to the same concussive loading to study the sensitivity of brain strain to inter-subject variability of the brain and WM fiber morphology. The simulation results show significant differences in maximum principal strain and axonal strain in local brain regions (one-way ANOVA test, p < 0.001), as well as their locations also vary among the subjects, demonstrating the need to further investigate the significance of subject-specific models. The techniques developed in this study may contribute to better evaluation of individual brain injury and the development of individualized head protection systems in the future. This study also contains general aspects the research community may find useful: on the use of experimental brain strain close to or at injury level for head model validation; the hierarchical image registration pipeline can be used to morph other head models, such as smoothed-voxel models.

Genetic characterization plays an important role in the conservation of threatened plants. In this study, the morphological, chemical, and genetic variability of 20 accessions of Citrullus colocynthis was determined by 14 phenotypic descriptors, five chemical descriptors, and 13 inter simple sequence repeat (ISSR) primers. The physiochemical variability analysis by clustering and principal component analysis classified 20 accessions into three populations. The vine length, weight, and diameter of the fruit were the main descriptors showing great morphological variations. Total flavonoids and phenolics were the main descriptors responsible for chemical variability. The phenolic contents have a positive correlation, whereas, the chlorophyll contents have a negative correlation with increasing altitude. The polymorphic information content of selected primers was found to be 0.34, indicating moderate polymorphism. The number of effective alleles, Shannon’s diversity index, and expected heterozygosity were found to be 1.22, 0.3, and 0.2, respectively. The analysis of molecular variance revealed 38% variation within populations and 62% variation among the populations. The cluster, population structure based on ΔK values, and principal coordinate analysis revealed three distinct populations. The multivariate regression analysis revealed that UBC802, UBC813, and UBC817 were significantly ( P  < 0.01) correlated with chemical descriptors, whereas UBC819, UBC831, and UBC834 were associated with morphological descriptors.

BACKGROUND: While many structures within the human body demonstrate anatomical variations, this is not typically the case for the iliopsoas muscle complex. However, the present paper describes a case of an anomalous psoas major composed of 4 different muscular heads in a 78-year-old male cadaver. MATERIALS AND METHODS: During a routine dissection of the right posterior abdominal wall, an unusual psoas major was observed, measured, and photographed. RESULTS: The psoas major was found to possess 4 muscular heads, otherwise the anatomy of the wall was normal. CONCLUSIONS: The presence of so many heads could interfere with the functions of the psoas major muscle. Therefore, this anatomical variation merits further study.

This study was conducted on forty-six wood apple ( Feronia limonia ) accessions planted in a randomized block design to evaluate the genetic diversity, quality traits, antioxidant properties, and nutrient composition. Numerous parameters, such as fruit weight (FW), seed number per fruit (SNF), total soluble solids in pulp of fruit (TSSP), potassium (K), magnesium (Mg), and yield per plant (YP), showed significant heterogeneity in the analysis, suggesting that these qualities could be improved genetically. Both stable and highly variable qualities across accessions were reflected in the coefficient of variation, which varied from 1.94% for root attributes to 132.07% for iron (Fe). To evaluate the possibility of selection in breeding programs, genetic parameters such as genetic and phenotypic coefficients of variation (GCV and PCV), heritability, and genetic advancement were computed. Traits such as FW and SNF exhibited high GCV and heritability, suggesting they are highly heritable and suitable for selection. On the other hand, characteristics such as calcium (Ca) demonstrated low heritability, underscoring the impact of environmental influences. Significant positive and negative correlations were found between several traits using correlation analysis. Fruit length (FL) had strong positive correlations with fruit weight (FW), fruit breadth (FB), and pulp weight (Pu), while iron content (Fe) had negative correlations with many other traits. Seven main components were found using principal component analysis (PCA), and PC1 accounted for 22.74% of the variance, which is a considerable amount of the total variation. Based on genetic diversity, a cluster analysis employing Tocher’s approach divided the accessions into discrete clusters. Cluster 2 had the highest mean values for FW, FL, and YP, indicating that it may be highly productive. The interactions between the variables were further elucidated by the genotypic path analysis, which demonstrated that yield potential was significantly influenced by indirect effects, especially through traits like FB, DSW, and Mg. These findings point out the critical role of precise trait selection in perennial crops, where long breeding cycles demand careful identification and prioritization of yield-associated traits. Emphasizing selection over broader breeding approaches ensures the retention and enhancement of traits that contribute most directly to long-term productivity and crop improvement.

The article presented the results of the assessment of the current state of Rhaponticum altaicum populations in the Karaganda and Akmola regions (Central and Northern Kazakhstan). The research provided the phytocenotic characteristics of habitats, biological features, and ontogenetic structure of populations, as well as data on the morphological variability of the species. The floristic composition of plant communities with Rh. altaicum was analyzed for the first time. In the plant communities with Rh. altaicum, 67 species from 38 genera and 23 families were identified. Most species were herbaceous perennials (92.5%) or hemicryptophytes (68.7%). Among the ecological groups, mesophytes (32.8%) dominated, and other groups were represented by transitional species: mesoxerophytes, xeromesophytes, mesogyrophytes, and hygromesophytes (49.2%). Therefore, in nature, Rh. altaicum occupied an intermediate place between meadow-bog and meadow communities. The species preferred moist meadows on slightly and moderately saline soils. In the ontogeny of Rh. altaicum, eight age-related states were identified, from seedlings to senile plants. The analysis of morphological indices allowed estimating that Rh. altaicum stem height was the most important; so, under unfavorable growing conditions, the stem height decreased. In the majority of populations, the upper leaf width was a highly variable trait, and the length and width of the lower leaf had low or moderate morphological variability. The highest positive correlation (significant at p = 0.05) was between plant height and lower leaf length, suggesting that taller plants had longer lower leaf blades. The studied populations were mainly dominated by virgin and medium-age generative plants. Sub-senile and senile plants were not detected, which is due to the difficulty of diagnosis as well as to the increasing anthropogenic load and narrow ecological amplitude of Rh. altaicum. Our study provided new insights into Rh. altaicum biology and ecology, thereby contributing to biodiversity conservation at a regional level.

The intricate patterning of diatom silica frustules at nanometer-to-micrometer scales makes them of interest for a wide range of industrial applications. For some of these applications, a specific size range in nanostructure is required and may be achieved by selecting species with the desired properties. However, as all biological materials, diatom frustules exhibit variability in their morphological parameters and this variability can to some extent be affected and controlled by environmental conditions. In this review, we explore the effects of different environmental factors including salinity, heavy metals, temperature, pH, extracellular Si(OH)4 or Ge(OH)4 concentration, light regime, UV irradiance, long-term cultivation, and biotic factors on the nanostructure of diatom frustules. This compilation of studies illustrates that it is possible to affect the nanostructure of diatom frustules in vivo by controlling different environmental factors as well as by direct chemical modification of frustules. We compare these methods and present examples of how these changes affect the range of variability as well as comparing the magnitude of size changes of the most promising methods.

This study analysed frost heave lands in the cold arid Leh–Ladakh region of the Himalaya, India through semi-detail field survey and remote sensing. Most of these sites are highland grasslands occurring along the alluvial plains of rivers in the Leh and Nubra valleys. The study identified the occurrence of some unique frost heave patterns whose morphometry varied from simple, isolated to complex ones with elongated, coalesced and superimposed bedforms. These lands can be further subdivided into vegetated and degraded types. The degraded forms exhibited several cracks, dry, collapsed and slump structures. Invasion of Cirsium arvense over native grass species, soil salinity and feeding pressure by livestock have been identified as major land degradation factors. C. arvense has replaced the native vegetation on frost heaves and has allowed Carex species to grow, which is known to degrade and deplete the pasture ecology.

The present study aimed to determine the variability in the Magnapothe oryzae isolates associated with the rice blast from the Jammu region. Leaf blast samples were collected from the rice growing areas of five districts of Jammu division during Kharif 2018 and 2019, and morphological, pathological and molecular variations among the thirty isolates were investigated. The conidial length ranged between 8.67 and 15.51 μm, and the conidial breadth ranged between 3.22 and 7.73 μm in all the isolates. The maximum conidia size was recorded in isolate Po25 (13.80-15.51 × 6.20–7.73 μm), and it was the minimum in isolate Po5 (8.67–10.30 × 3.22–5.46 μm). The incubation period of all the M. oryzae isolates ranged from 5.9 to 8.6 days in different rice varieties. The molecular analysis using 25 SSR primer pairs revealed higher genetic variability in the 23 isolates of M. oryzae . Phylogenetic analysis based on similarity coefficient grouped the isolates into two major clusters, I and II, and four sub-clusters: IA, IB, IIA and IIB.

Geometric morphometric analyses were performed on the Neotropical ostracod Cytheridella including recent populations from Florida, Yucatán, Colombia, and Brazil. Generalized least-squares Procrustes analyses were applied to left and right valves of adult females and males and to A-1 to A-3 juveniles. The analyses show that the prevailing shape variability is in the outline of the valves. Further characters defining the variability range are the anterior pore conuli 2 and 4 (LM 2, LM 4) and the connection point between transversal sulcus and the extension of the posterior lobe (LM 6). Relative Warps Analysis enabled delineation of the whole-shape disparity and revealed a geographical pattern in the morphological variability that is apparent in adults and juveniles. Females show greatest morphological disparity, whereas juveniles are more variable on the population scale. Differences in hard- and soft-part morphology identify the specimens from Yucatán as new a morphospecies. Different hydrological or hydrochemical conditions may have led to the evolution of the new species. Cytheridella has occurred in the Neotropics since the Oligocene with a similar distribution to that in the Recent. Avian dispersal may repeatedly reintroduce C. ilosvayi to Yucatánian populations possibly explaining the sympatric occurrence of 2 Cytheridella morphospecies. Our findings promote the benefit of investigating morphological variability quantitatively to detect regional morphotypes and ultimately to contribute to evaluations of biodiversity.