Variation In Size Research Articles

Influence of various pilot hole profiles on pedicle screw fixation strength in minimally invasive and traditional spinal surgery: a comparative biomechanical study.

Despite advancements in pedicle screw design and surgical techniques, the standard steps for inserting pedicle screws still need to follow a set of fixed procedures. The first step, known as establishing a pilot hole, also referred to as a pre-drilled hole, is crucial for ensuring screw insertion accuracy. In different surgical approaches, such as minimally invasive or traditional surgery, the method of creating pilot holes varies, resulting in different pilot hole profiles, including variations in size and shape. The aim of this study is to evaluate the biomechanical properties of different pilot hole profiles corresponding to various surgical approaches. Commercially available synthetic L4 vertebrae with a density of 0.16g/cc were utilized as substitutes for human bone. Four different pilot hole profiles were created using a 3.0mm cylindrical bone biopsy needle, 3.6mm cylindrical drill, 3.2-5.0mm conical drill, and 3.2-5.0mm conical curette for simulating various minimally invasive and traditional spinal surgeries. Two frequently employed screw shapes, namely, cylindrical and conical, were selected. Following specimen preparation, screw pullout tests were performed using a material test machine, and statistical analysis was applied to compare the mean maximal pullout strength of each configuration. Conical and cylindrical screws in these four pilot hole configurations showed similar trends, with the mean maximal pullout strength ranking from high to low as follows: 3.0mm cylindrical biopsy needle, 3.6mm cylindrical drill bit, 3.2-5.0mm conical curette, and 3.2-5.0mm conical drill bit. Conical screws generally exhibited a greater mean maximal pullout strength than cylindrical screws in three of the four different pilot hole configurations. In the groups with conical pilot holes, created with a 3.2-5.0mm drill bit and 3.2-5.0mm curette, both conical screws exhibited a greater mean maximal pullout strength than did cylindrical screws. The strength of this study lies in its comprehensive comparison of the impact of various pilot hole profiles commonly used in clinical procedures on screw fixation stability, a topic rarely reported in the literature. Our results demonstrated that pilot holes created for minimally invasive surgery using image-guided techniques exhibit superior pullout strength compared to those utilized in traditional surgery. Therefore, we recommend prioritizing minimally invasive surgery when screw implantation is anticipated to be difficult or there is a specific need for stronger screw fixation. When opting for traditional surgery, image-guided methods may help establish smaller pilot holes and increase screw fixation strength.

A data-driven polynomial chaos method for uncertainty quantification of a subsonic compressor cascade with stagger angle errors

The probability-based uncertainty quantification (UQ) methods require a large amount of sampled data to construct the probability distribution of uncertain input parameters. However, it is a common situation that only limited and scarce sampled data are available in engineering applications due to expensive tests. In the present paper, the Data-Driven Polynomial Chaos (DDPC) method is adopted, which can propagate input uncertainty in the case of scarce sampled data. The calculation accuracy and convergence of the self-developed DDPC method are validated by a nonlinear test function. Subsequently, the DDPC method is applied to investigate the uncertain impact of stagger angle errors on the aerodynamic performance of a subsonic compressor cascade. A family of manufacturing error data of stagger angles was obtained from the real compressor blades. Based on the limited measurement data, the DDPC method combined with Computational Fluid Dynamics (CFD) simulation is employed to quantify the performance impact of the compressor cascade. The results show that the performance dispersion under off-design conditions is more prominent than that under design conditions. The actual aerodynamic performance deviating from the nominal performance is not a small probability event, and the probability of deviating from the nominal loss coefficient and exit flow angle by more than 1% can reach up to 47.6% and 36.8% under high incidence i = 7°. Detailed analysis shows that stagger angle errors have a significant effect on the flow state near the leading edge, resulting in variations in separation bubble size and boundary layer thickness.

Several Numerical Simulation Methods for the Time-Dependent Schrödinger Equation

The time-dependent Schrödinger equation can be solved using the Houbolt difference scheme or the space-time polynomial particular solutions method, with the former performing well in dissipative problems and the latter being suitable for wave-like problems. To handle variations in time-step sizes while overcoming numerical oscillations in non-smooth regions, these two methods are coupled. The time-domain is handled using the Houbolt difference format, while the spatial domain is handled using the method of polynomial particular solutions. The numerical results show that the advantages of each method are preserved. Additionally, this hybrid approach can be replaced with other difference methods and meshless methods to meet various numerical solution needs.

Association of Alpha-Crystallin with Human Cortical and Nuclear Lens Lipid Membrane Increases with the Grade of Cortical and Nuclear Cataract.

Eye lens α-crystallin has been shown to become increasingly membrane-bound with age and cataract formation; however, to our knowledge, no studies have investigated the membrane interactions of α-crystallin throughout the development of cataracts in separated cortical membrane (CM) and nuclear membrane (NM) from single human lenses. In this study, four pairs of human lenses from age-matched male and female donors and one pair of male lenses ranging in age from 64 to 73 years old (yo) were obtained to investigate the interactions of α-crystallin with the NM and CM throughout the progression of cortical cataract (CC) and nuclear cataract (NC) using the electron paramagnetic resonance spin-labeling method. Donor health history information (diabetes, smoker, hypertension, radiation treatment), sex, and race were included in the data analysis. The right eye lenses CM and NM investigated were 64 yo male (CC: 0), 68 yo male (CC: 3, NC: 2), 73 yo male (CC: 1, NC: 2), 68 yo female (CC: 3, NC: 2), and 73 yo female (CC: 1, NC: 3). Similarly, left eye lenses CM and NM investigated were 64 yo male (CC: 0), 68 yo male (CC: 3, NC: 2), 73 yo male (CC: 2, NC: 3), 68 yo female (CC: 3, NC: 2), and 73 yo female (CC: 1, NC: 3). Analysis of α-crystallin binding to male and female eye lens CM and NM revealed that the percentage of membrane surface occupied (MSO) by α-crystallin increases with increasing grade of CC and NC. The binding of α-crystallin resulted in decreased mobility, increased order, and increased hydrophobicity on the membrane surface in male and female eye lens CM and NM. CM mobility decreased with an increase in cataracts for both males and females, whereas the male lens NM mobility showed no significant change, while female lens NM showed increased mobility with an increase in cataract grade. Our data shows that a 68 yo female donor (long-term smoker, pre-diabetic, and hypertension; grade 3 CC) showed the largest MSO by α-crystallin in CM from both the left and right lens and had the most pronounced mobility changes relative to all other analyzed samples. The variation in cholesterol (Chol) content, size and amount of cholesterol bilayer domains (CBDs), and lipid composition in the CM and NM with age and cataract might result in a variation of membrane surface mobility, membrane surface hydrophobicity, and the interactions of α-crystallin at the surface of each CM and NM. These findings provide insight into the effect of decreased Chol content and the reduced size and amount of CBDs in the cataractous CM and NM with an increased binding of α-crystallin with increased CC and NC grade, which suggests that Chol and CBDs might be a key component in maintaining lens transparency.

CellT-Net: A Composite Transformer Method for 2-D Cell Instance Segmentation.

Cell instance segmentation (CIS) via light microscopy and artificial intelligence (AI) is essential to cell and gene therapy-based health care management, which offers the hope of revolutionary health care. An effective CIS method can help clinicians to diagnose neurological disorders and quantify how well these deadly disorders respond to treatment. To address the CIS task challenged by dataset characteristics such as irregular morphology, variation in sizes, cell adhesion, and obscure contours, we propose a novel deep learning model named CellT-Net to actualize effective cell instance segmentation. In particular, the Swin transformer (Swin-T) is used as the basic model to construct the CellT-Net backbone, as the self-attention mechanism can adaptively focus on useful image regions while suppressing irrelevant background information. Moreover, CellT-Net incorporating Swin-T constructs a hierarchical representation and generates multi-scale feature maps that are suitable for detecting and segmenting cells at different scales. A novel composite style named cross-level composition (CLC) is proposed to build composite connections between identical Swin-T models in the CellT-Net backbone and generate more representational features. The earth mover's distance (EMD) loss and binary cross entropy loss are used to train CellT-Net and actualize the precise segmentation of overlapped cells. The LiveCELL and Sartorius datasets are utilized to validate the model effectiveness, and the results demonstrate that CellT-Net can achieve better model performance for dealing with the challenges arising from the characteristics of cell datasets than state-of-the-art models.

Temporal variations in female moose responses to roads and logging in the absence of wolves.

Animal movements, needed to acquire food resources, avoid predation risk, and find breeding partners, are influenced by annual and circadian cycles. Decisions related to movement reflect a quest to maximize benefits while limiting costs, especially in heterogeneous landscapes. Predation by wolves (Canis lupus) has been identified as the major driver of moose (Alces alces) habitat selection patterns, and linear features have been shown to increase wolf efficiency to travel, hunt, and kill prey. However, few studies have described moose behavioral response to roads and logging in Canada in the absence of wolves. We thus characterized temporal changes (i.e., day phases and biological periods) in eastern moose (Alces alces americana) habitat selection and space use patterns near a road network in a wolf-free area located south of the St. Lawrence River (eastern Canada). We used telemetry data collected on 18 females between 2017 and 2019 to build resource selection functions and mixed linear regressions to explain variations in habitat selection patterns, home-range size, and movement rates. Female moose selected forest stands providing forage when movement was not impeded by snow cover (i.e., spring/green-up, summer/rearing, fall/rut) and stands offering protection against incidental predation during calving. In winter, home-range size decreased with an increasing proportion of stands providing food and shelter against harsh weather, limiting the energetic costs associated with movement. Our results reaffirmed the year-round aversive effect of roads, even in the absence of wolves, but the magnitude of this avoidance differed between day phases, being lower during the "dusk-night-dawn" phase, perhaps due to a lower level of human activity on and near roads. Female moose behavior in our study area was similar to what was observed in landscapes where moose and wolves cohabit, suggesting that the risk associated with humans, perceived as another type of predator, and with incidental predators (coyote Canis latrans, black bear Ursus americanus), equates that of wolf predation in heavily managed landscapes.

Insights into the consequence of (Al–Zn) dual-doping on structural, morphological, and optoelectrical properties of CdO thin films

The present study explores the structural, morphological, optical, and electrical properties of spray pyrolyzed (Al–Zn) dual-doped CdO thin films. The un-doped and (Al–Zn) dual-doped CdO thin films have been deposited on glass substrate using spray pyrolysis route at 325 °C. The physical properties of the doped samples were analyzed as a function of Zn concentration (2–5 mol%) with constant Al (3 mol%) concentration. XRD analysis confirms the successful incorporation of (Al–Zn) dual-doping into CdO crystal as well as the polycrystalline nature was evident. No phase transitions were apparent from XRD data while revealing the single cubic structure of all the samples. The surface morphology of the samples studied by SEM. It shows the formation of rock-shaped microstructure and the variation of grain size with doping concentrations. Optical analysis was done using UV–vis spectroscopy within the range of 300–1200 nm. Maximum value of transmittance was attained for 3% (Zn–Al)-doped CdO sample. The dual doping exhibits the broadening of band gap values (2.61–3.84 eV) whereas a decrease in extinction coefficient was noticed as a function of Zn doping concentration. Electrical analysis was done using the four-probe method and a high resistivity was seen for higher Zn concentration. Obtained results and precise comparison with some similar films suggested that 2% Zn and 3% Al co-doping can be a suitable candidate for optoelectronic devices.

Can the construction of a high-speed rail alleviate haze pollution: an empirical analysis based on social networks and dynamic spatial econometric models.

With the increase in haze pollution in Chinese cities, answering the question of whether using a high-speed rail (HSR) as a green and efficient transportation system can alleviate haze pollution in China has become a research hotspot. This study empirically tests the impact of HSR network construction on haze pollution and its spatial spillover effects. (1) The construction of a HSR would have a mitigation effect on haze pollution in node cities and surrounding cities, and the more developed the HSR is, the more significant that this effect would be. (2) Haze pollution persists for a long time, the haze pollution from the previous year may have a positive promoting effect on the haze pollution in the following year. (3) The use of a HSR reduces haze pollution by replacing traditional road transportation and promoting industrial structure upgrading and technological innovation. (4) The inhibitory effect of HSR use on haze pollution varies due to regional differences and variation in city size.

Molecular interactions of acids and salts with polyampholytes.

The Hofmeister series characterizes the ability of salt anions to precipitate polyampholytes/proteins. However, the variation of protein size in the bulk solution of acids and the effect of salts on the same have not been studied well. In this article, the four acids (CH3COOH, HNO3, H2SO4, andHCl) and their effects on the hydrodynamic radius (RH) of gelatin in the bulk solution are investigated. The effects of Na salt with the same anions are also considered to draw a comparison between the interactions of acids and salts with polyampholytes. It is suggested that the interactions of polyampholytes with acids are different from those of salts. The interaction series of polyampholytes with acids with respect to the RH of the polyampholyte is CH3COO->NO3->Cl->SO42- whereas the interaction series with salts is SO42->CH3COO->Cl->NO3-. These different interactions are due to equilibration between acid dissociation and protonation of polyampholytes. Another important factor contributing to the interactions in weak acids is the fact that undissociated acid hinders the movement of dissociated acid. Experiments and simulations were performed to understand these interactions, and the results were identical in terms of the trend in RH (from the experiments) and the radius of gyration (Rg) (from the simulations). It is concluded that the valence of ions and dissociation affect the interaction in the case of acids. However, the interactions are influenced by the kosmotropic and chaotropic effect, hydration, and mobility in the case of salts.

Mechanisms, costs, and carry-over effects of cannibal-induced developmental plasticity in invasive cane toads.

Inducible defences can improve survival in variable environments by allowing individuals to produce defences if they detect predators. These defences are often expressed as inter-related developmental, morphological, and behavioural changes. However, producing defences can incur costs, which may be expressed immediately and/or during subsequent life stages. In Australia, waterborne cues of potentially cannibalistic conspecific tadpoles induce hatchlings of invasive cane toads to accelerate their developmental rate, thereby reducing their window of vulnerability. However, the mechanisms and costs of such accelerated development are poorly understood, and whether cane toad embryos show cannibal-induced plasticity in other traits is unknown. Here, we found no evidence of altered time of hatching for embryos exposed to non-feeding conspecific cannibal tadpole cues. Additionally, hatchling dispersal behaviours were not affected by exposure to these cues. However, developmental acceleration of hatchlings induced by exposure to tadpole cues was accompanied by reduced hatchling growth, indicating a trade-off between these processes. At the conclusion of the hatchling stage, cannibal-exposed individuals were smaller and morphologically distinct from control siblings. This size reduction affected performance during the subsequent tadpole stage: smaller cannibal-exposed individuals were more likely to die, and initial size tended to be positively associated with subsequent tadpole growth and development across treatments (respectively, p = .07 and p = .06). However, even accounting for variation in initial size, there was an additional negative effect of cannibal exposure on tadpole growth and development, demonstrating that the fitness costs associated with developmental acceleration are not entirely attributable to size reductions.

Motor control: Snake neurons speed up

How are motor neurons tuned for very different jobs? Classic work has focused on variations in motor neuron size and their premotor networks. New results in rattlesnakes show that shifting a motor neuron's temporal precision can be as simple as changing its potassium channel conductance.

Predator-induced shape plasticity in Daphnia pulex.

All animals and plants respond to changes in the environment during their life cycle. This flexibility is known as phenotypic plasticity and allows organisms to cope with variable environments. A common source of environmental variation is predation risk, which describes the likelihood of being attacked and killed by a predator. Some species can respond to the level of predation risk by producing morphological defences against predation. A classic example is the production of so-called 'neckteeth' in the water flea, Daphnia pulex, which defend against predation from Chaoborus midge larvae. Previous studies of this defence have focussed on changes in pedestal size and the number of spikes along a gradient of predation risk. Although these studies have provided a model for continuous phenotypic plasticity, they do not capture the whole-organism shape response to predation risk. In contrast, studies in fish and amphibians focus on shape as a complex, multi-faceted trait made up of different variables. In this study, we analyse how multiple aspects of shape change in D. pulex along a gradient of predation risk from Chaoborus flavicans. These changes are dominated by the neckteeth defence, but there are also changes in the size and shape of the head and the body. We detected change in specific modules of the body plan and a level of integration among modules. These results are indicative of a complex, multi-faceted response to predation and provide insight into how predation risk drives variation in shape and size at the level of the whole organism.

Green, charismatic, microendemic, and threatened: breeding biology of the leaf frog Pithecopus rusticus (Anura: Hylidae: Phyllomedusinae)

ABSTRACT Pithecopus rusticus is a small and charismatic leaf frog species known only from the type locality, in the Brazilian Subtropical Highland Grasslands of the Atlantic Forest, southern Brazil. In this study, we describe aspects of the reproductive biology and populational size of P. rusticus, encompassing the characterization of breeding season, microhabitat use for vocalization and spawning, the variation in body size of males and females and operational sex ratio, as well as explore the influence of climate variables on the abundance of individuals. We collected information from 2015 to 2021, mainly in the breeding seasons of 2015/16 and 2017/18. We recorded 91 individuals of P. rusticus, with a recapture rate of 61% in the 2015/16 breeding season and 57% in the 2017/18 breeding season. The estimated population size was 28.9 individuals for the 2015/16 breeding season and 21 individuals for the 2017/18 breeding season. The temporal reproductive pattern was intermediate, being concentrated in spring to early summer months (October to January), and the male calling activity differed throughout the night, increasing from 9pm onwards. The abundance of P. rusticus was significantly related with relative air humidity. We found sexual size dimorphism, with females larger than males, and a male-skewed operational sex ratio. Males and females used Poaceae and Cyperaceae leaves located close to water. Spawns contained 43 ± 5 eggs, with a diameter of 3.26 ± 0.45 mm, and were deposited on leaves of Senecio (Asteraceae) and Eriocaulon (Eriocaulaceae). Information on natural history is essential to support the implementation and success of in situ and ex situ conservation strategies for this endangered species.

Anisotropy of microstructure, mechanical properties and thermal expansion in Invar 36 alloy fabricated via laser powder bed fusion

Invar 36 is a renowned iron-nickel alloy with an ultra-low coefficient of thermal expansion (CTE), which is widely used in aerospace and precision instruments. Laser powder bed fusion (LPBF) as a prevalent metal additive manufacturing technique could break through the limitations of traditional processes, such as low material utilization and difficulties in forming complex structures. In this work, Invar 36 alloy specimens were fabricated via LPBF process in 0° (H0 specimen), 45° (D45 specimen), and 90° (V90 specimen) build orientations. The microstructure, tensile properties, thermal expansion, and magnetic properties of the three orientations specimens were comprehensively investigated, and the anisotropy of microstructure, yield strength and CTE were analyzed. The V90 specimen exhibited the highest elongation (62.70%), while the D45 specimen owned the highest yield strength (496 MPa). The anisotropic mechanical properties can be attributed to variations in dislocation density, grain size, and intrinsic yield strength. The CTE of LPBF-fabricated Invar 36 alloy specimens were all lower than that of traditional manufacturing process at all temperature ranges. Since CTE is more related to magnetic properties, not sensitive to microstructure, the anisotropy of CTE is not significant in three build orientations. This study has significant implications to produce Invar 36 alloy devices with exceptional properties and 3D dimensional stability via the LPBF process.

From imaging to precision: low cost and accurate determination of stereotactic coordinates for brain surgery Sapajus apella using MRI.

The capuchin monkey (Sapajus apella), a New World monkey species, exhibits prominent characteristics that make it an ideal model for neuroscience research. These characteristics include its phylogenetic traits, telencephalization coefficient, anatomical structures and pathways, genetic profile, immune responses, cognitive abilities, and complex behavioral repertoires. Traditionally, methodologies for stereotactic neurosurgery in research models have relied on the use of brain atlases. However, this approach can lead to errors due to the considerable variation in brain size and shape among individual monkeys. To address this issue, we developed a protocol for deriving individual coordinates for each monkey using a straightforward and relatively inexpensive method involving MRI imaging. Our protocol utilizes a specially designed, 3D-printed stereotactic head-holder that is safe to use with an MR magnet, non-invasive placement of fiducial markers, and post-processing with open-source software. This approach enhances MRI data visualization, improves anatomical targeting, and refines the design of neurosurgical experiments. Our technique could also prove beneficial in other areas of neuroscience research that require accurate calculation of stereotaxic coordinates. Furthermore, it could be useful for other nonhuman primate species for which brain atlases are typically unavailable.

Arabidopsis response to copper is mediated by density and root exudates: Evidence that plant density and toxic soils can shape plant communities.

Plants grown at high densities show increased tolerance to heavy metals for reasons that are not clear. A potential explanation is the release of citrate by plant roots, which binds metals and prevents uptake. Thus, pooled exudates at high plant densities might increase tolerance. We tested this exclusion facilitation hypothesis using mutants of Arabidopsis thaliana defective in citrate exudation. Wild type Arabidopsis and two allelic mutants for the Ferric Reductase Defective 3 (FRD3) gene were grown at four densities and watered with copper sulfate at four concentrations. Plants were harvested before bolting and dried. Shoot biomass was measured, and shoot material and soil were digested in nitric acid. Copper contents were determined by atomic absorption. In the highest-copper treatment, density-dependent reduction in toxicity was observed in the wild type but not in FRD3 mutants. For both mutants, copper concentrations per gram biomass were up to seven times higher than for wild type plants, depending on density and copper treatment. In all genotypes, total copper accumulation was greater at higher plant densities. Plant size variation increased with density and copper treatment because of heterogeneous distribution of copper throughout the soil. These results support the hypothesis that citrate exudation is responsible for density-dependent reductions in toxicity of metals. Density-dependent copper uptake and growth in contaminated soils underscores the importance of density in ecotoxicological testing. In soils with a heterogeneous distribution of contaminants, competition for nontoxic soil regions may drive size hierarchies and determine competitive outcomes.

Integrated approach for detection of SARS-CoV-2 and its variant by utilizing LAMP and ARMS-PCR

Global impact of COVID-19 pandemic has heightened the urgency for efficient virus detection and identification of variants such as the Q57H mutation. Early and efficient detection of SARS-CoV-2 among densely populated developing countries is paramount objective. Although RT-PCR assays offer accuracy, however, dependence on expansive kits and availability of allied health resources pose an immense challenge for developing countries. In the current study, RT-LAMP based detection of SARS-Cov-2 with subsequent confirmation of Q57H variant through ARMS-PCR was performed. Among the 212 collected samples, 134 yielded positive results, while 78 tested negative using RT-LAMP. Oropharyngeal swabs of suspected individuals were collected and processed for viral RNA isolation. Isolated viral RNA was processed further by using either commercially available WarmStart Master Mix or our in house developed LAMP master mix separately. Subsequently, the end results of each specimen were evaluated by colorimetry. For LAMP assays, primers targeting three genes (ORF1ab, N and S) were designed using PrimerExplorer software. Interestingly, pooling of these three genes in single reaction tube increased sensitivity (95.5%) and specificity (93.5%) of LAMP assay. SARS-CoV-2 positive specimens were screened further for Q57H mutation using ARMS-PCR. Based on amplicon size variation, later confirmed by sequencing, our data showed 18.5% samples positive for Q57H mutation. Hence, these findings strongly advocate use of RT-LAMP-based assay for SARS-CoV-2 screening within suspected general population. Furthermore, ARMS-PCR also provides an efficient mean to detect prevalent mutations against SARS-Cov-2.

Effect of ecological and anthropogenic factors on grouping patterns in African lions across Kenya.

Social carnivores frequently live in fission-fusion societies, where individuals that share a common territory or home range may be found alone, in subgroups, or altogether. Absolute group size and subgroup size is expected to vary according to resource distribution, but for species that are susceptible to anthropogenic pressures, other factors may be important drivers. African lions (Panthera leo) are the only truly social felid and lion prides are characterized by fission-fusion dynamics with social groups frequently splitting and reforming, and subgroup membership can change continuously and frequently. The number of individuals in a group can be reflective of social, ecological, and anthropogenic conditions. This dynamic behavior makes understanding lion grouping patterns crucial for tailoring conservation measures. The evolution of group living in lions has been the topic of numerous studies, and we drew on these to formulate hypotheses relating to group size and subgroup size variation. Based on data collected from 199 lion groups across eight sites in Kenya, we found that group sizes were smaller when lions were closer to human settlements, suggesting that edge effects are impacting lions at a national scale. Smaller groups were also more likely when they were far from water, and were associated with very low and very high levels of non-tree vegetation. We found significant differences between the study sites, with the Maasai Mara having the largest groups (mean ± SD = 7.7 ± 4.7, range = 1-19), and Amboseli conservation area the smallest (4.3 ± 3.5, range = 1-14). While long-term studies within a single site are well suited to thoroughly differentiate between absolute group size and subgroup size, our study provides unique insight into the correlates of grouping patterns in a vulnerable species at a national scale.

Breaking the Law: Is It Correct to Use the Converse Bergmann Rule in Ceroglossus chilensis? An Overview Using Geometric Morphometrics.

The converse Bergmann's rule is a pattern of body size variation observed in many ectothermic organisms that contradicts the classic Bergmann's rule and suggests that individuals inhabiting warmer climates tend to exhibit larger body sizes compared to those inhabiting colder environments. Due to the thermoregulatory nature of Bergmann's rule, its application among ectotherms might prove to be more complicated, given that these organisms obtain heat by absorbing it from their habitat. The existence of this inverse pattern therefore challenges the prevailing notion that larger body size is universally advantageous in colder climates. Ceroglossus chilensis is a native Chilean beetle that has the largest latitudinal range of any species in the genus, from 34.3° S to 47.8° S. Within Chile, it continuously inhabits regions extending from Maule to Aysen, thriving on both native and non-native forest species. Beyond their remarkable color variation, populations of C. chilensis show minimal morphological disparity, noticeable only through advanced morphological techniques (geometric morphometrics). Based on both (1) the "temperature-size rule", which suggests that body size decreases with increasing temperature, and (2) the reduced resource availability in high-latitude environments that may lead to smaller body sizes, we predict that C. chilensis populations will follow the converse Bergmann's rule. Our results show a clear converse pattern to the normal Bergmann rule, where smaller centroid sizes were found to be measured in the specimens inhabiting the southern areas of Chile. Understanding the prevalence of the converse Bergmann's rule for ectotherm animals and how often this rule is broken is of utmost importance to understand the underlying mechanisms allowing organisms to adapt to different environments and the selective pressures they face.

Modeling Physical and Physiological Processes Reveals the Role of Turbulence in the Prerequisites for Microcystis Blooms

AbstractHarmful algal blooms of Microcystis have become a global problem. Turbulence, a determining factor affecting blooms, not only disperses surface scum but also controls the growth of Microcystis. Numerous studies have analyzed the effects of turbulence on the growth and colony size of Microcystis in laboratories, but the turbulence thresholds for Microcystis growth and colony disaggregation in the field are difficult to determine due to the complex environment. In addition, the quantitative contribution of turbulence‐driven blooms and the intrinsic mechanisms of the spatial distribution responding to turbulence are unclear. In this study, a fully integrated filed scale computational model focusing on turbulence‐driven blooms was developed, which incorporates physical processes (turbulence‐induced vertical mixing, VMT) and physiological processes such as buoyancy‐controlling transport (BCT), turbulence‐induced colony size variation (CSV), and growth rate variation (GRV). We performed model sensitivity analysis and evaluated the effects of turbulence intensity and duration on the biomass and vertical distribution of Microcystis. The results show that the optimal turbulence dissipation rate for Microcystis growth in the field is 1.0 × 10−5 m2/s3 and the critical turbulence dissipation rate for aggregation distribution is 3.81 × 10−6 m2/s3 in shallow lakes. A quantitative comparison of the effects of physical/physiological processes on blooms shows that physiological processes (CSV, GRV, and BCT) are critical for biomass enrichment, and the accumulation of Microcystis at the water surface is dominated by physical processes (VMT). This study reveals the mechanisms of turbulence‐driven Microcystis blooms and provides new insights for algal bloom prediction and control.