Tail Shape Research Articles

Temperature behavior of the velocity autocorrelation function in large MD models of water.

Velocity autocorrelation functions (VACFs) were calculated using the molecular dynamics method in the TIP4P/2005 and SPC/E water models of 157 464 molecules at temperatures ranging from 250 to 370K. The large size of the models and the high accuracy of the calculations allow us to reliably compute the long-time tails of the VACFs, showing that they systematically change shape from hydrodynamic (argon-like) at high temperatures to that typical of supercooled liquids at low temperatures. These tails in the range of 2-10ps can be well fitted by a combination of two power functions: At-3/2 - Bt-β (A, B > 0, β ≈ 2). It is found that the amplitude of the hydrodynamic asymptote, A, approaches zero as the temperature decreases, thereby rendering the negative power-law decay,-Bt-2, the dominant term within the specified time interval. The presence of a negative -Bt-2 decay in the time interval of 2-10ps determines the specific shape of the VACF long-time tail of water, distinguishing it from ordinary simple liquids. The amplitude B, which is always non-zero, demonstrates a slight increase with rising temperature. At medium temperatures, weak but well-defined damped oscillations are observed on the VACF in the 0.5-2ps interval.

P-154 Structural changes of the human sperm tail during the early post-fertilization

Abstract Study question What happens to the sperm tails that are no longer needed after the goal of fertilization has been achieved? Summary answer The sperm tail lost its fibrous sheath and changed to a coiled morphology with a whisker root-like structure at the tip during the early post-fertilization. What is known already The sperm tail has been thought to play only a role in allowing the head and neck to reach the oocyte. The flagellum is found in the mammalian sperm tail and consists of a middle, main, and terminal part. It also contains an axon composed of two central microtubules surrounded by nine peripheral microtubule doublets (9d + 2s microtubule pattern) surrounded by an accessory structure called the fibrous sheath (FS), but few studies have been conducted on the post-fertilization fate of the mammalian sperm tail. Study design, size, duration To investigate sperm tail structure from the pronuclear stage to the second cleavage, we used abnormally fertilized oocytes derived from either conventional in vitro fertilization (cIVF, n = 41) or intracytoplasmic sperm injection (ICSI, n = 11). In this study, abnormally fertilized oocytes were collected between March 2022 and November 2023 and subjected to immunofluorescence analysis and field emission scanning electron microscopy (FE-SEM) analysis. Participants/materials, setting, methods Under ethical approval, abnormally fertilized oocytes were donated by infertile couples undergoing cIVF or ICSI cycles at the Yamashita Shonan Yume Clinic in Japan. Informed consent was obtained from all participants. Immunofluorescence assay was performed to analyze sperm tail morphology using antibodies against H3K27me3, α-tubulin, and AKAP4. FE-SEM analysis was performed to detect the 9d + 2s structure characteristic of the sperm tail axon. Main results and the role of chance Tri-pronuclear zygotes derived from conventional in vitro fertilization (cIVF-derived 3PN) had two male pronuclei, whereas those derived from intracytoplasmic sperm injection (ICSI-derived 3PN) had one. Each zygote had the same number of coiled microtubule structures as the male pronucleus, and the 9d + 2s structure characteristic of the axon was identified, suggesting a sperm tail. No difference in sperm tail shape was observed between ICSI-derived 3PN and cIVF-derived 3PN. AKAP4, which is specifically localized in the FS associated with the principal piece of the flagellum, was observed in sperm tails attached to the zona pellucida but not in those in the oocyte, suggesting that the FS of the flagellum is lost before the pronuclear stage, leaving the microtubules of the axonemes exposed. The sperm tail was attached to one of the spindle poles during the first cleavage of abnormally fertilized oocytes, but no differences in the structure of the spindle pole with or without the sperm tail were observed. The tip of the sperm tail was branched like a “whisker root”, suggesting that the sperm tail was degraded from the end, but the degree of tip branching did not differ from the pronuclear stage to the second cleavage. Limitations, reasons for caution Normal fertilized oocytes were not used in this study because they are used for clinical treatment. The cell biological significance of sperm tail branching is currently unknown and requires further experimentation. Wider implications of the findings These findings shed light on the processes that occur during human fertilization, suggest new roles for the sperm tail, and may have implications for assisted fertilization approaches in the future. Trial registration number not applicable

Body shape divergence of paradise thread fish (Polynemus paradiseus) collected from different coastal habitats of southern Bangladesh: A multivariate approach for population discrimination

The paradise thread fish (Polynemus paradiseus) is a commercially and ecologically important euryhaline fish that primarily lives in diversified coastal and estuarine habitats. A comprehensive understanding of the divergence in body shape and discrimination in population parameters related to habitats is crucial for fisheries management and conservation endeavours. To test whether significant morphological differences exist between P. paradiseus populations inhabiting different coastal environments, a total of 366 individuals (198 male and 168 female) were collected from five distant places over three zones- Cox's Bazar (Bakkhali River) and Chattogram (Karnaphuli River) in the southeast coastal regions, Noakhali (lower Meghna River) in the southcentral zone, and Khulna (Shibsa River) and Borguna (Bishkhali River) in the southwest zones adjacent to the Bay of Bengal, Bangladesh in November 2022. The truss networking and geometric morphometric analysis (GMA) indicated variations in body shape among P. paradiseus individuals induced by sexual dimorphism. Wireframe graphs demonstrated that female individuals had wider dorsal-abdominal parts than males. Using the truss networking dataset for five coastal habitats, multivariate analyses revealed two overlapping clusters: southwest (Borguna and Khulna) populations in one cluster, while central (Noakhali) and southeast (Chattogram and Cox's Bazar) populations form separate clusters. The GMA also illustrated that the Khulna-Borguna population was located near the opposite end of the Chattogram-Cox's Bazar population axis, and the Noakhali populations were somewhat in the middle, with a high degree of overlap. Wireframe graphs displayed a significant body shape variations among populations, mainly in the snout shape, the width of the dorsal-abdominal part, the tail shape, and the head shape. The Discriminant Function Analysis revealed that there were pronounced variations in body shape between two populations located in distant regions, while there were minimum variations between two populations located close to each other. This study underscores the effectiveness of landmark-based truss networking and geometric morphometrics in discerning morphological variations across different habitats. These variations likely hold adaptive significance and are critical for informed population management and conservation strategies in the population structure of euryhaline P. paradisus.

A High-gain omnidirectional conformal antenna on the aerial vehicle

Abstract A series-fed conformal microstrip antenna with the tail wing of a UAV(Unmanned Aerial Vehicle)is proposed and implemented in this paper. In the target frequency band, the antenna has a nice performance of omnidirectional radiation and high gain, which easily conforms with the tail wing structure, achieving good wind resistance characteristics and meeting the strict aerodynamic requirements of the UAV. The antenna radiator is etched onto a printed board with a dielectric constant of 2.2 and a size of 644mm×112mm×4mm. In addition, the radiator is fixed with PMI form and formed a tail shape with surrounding glass fiber cloth, which has strong rigidity as a whole and has passed the flight test. The test results show that the antenna achieves a gain of more than 4.2 dBi at 564-676 MHz, a gain of more than 5.6 dBi at 600-650 MHz, and a gain of less than 3dB at 564-676MHz. This proposed antenna has a reasonable structure and good performance, which is verified by engineering experiments and is suitable for harsh environment requirements. It is expected that this antenna has wide applications in high-speed UAV communication.

Evaluation of Morphological Variants of Soft Palate in Individuals with Different Skeletal Patterns Using Digital Lateral Cephalometric Images

Background and Objectives The soft palate has morphological variations in lateral cephalometric images. Several studies are available on the analysis of the dimensions of the soft palate, but few have investigated the morphology of the soft palate. The aim of this study is to investigate the relationship between morphological variations of the soft palate and types of malocclusion in Ahvaz, southwest of Iran. Subjects and Methods In this descriptive-analytical study, the lateral cephalometric images of 162 patients with abnormal skeletal pattern available in the archive of the Radiology Department of Jundishapur School of Dentistry in Ahvaz were used. The radiographs were divided into 6 groups (leaf shape, rat tail shape, butt like, straight line, distorted soft palate, and crook shape) under the supervision of a radiologist. The data were analyzed to determine the relationship between soft palate morphology and skeletal pattern . Results The results showed that 51.2% of the patients’ skeletal pattern were class two, 37% were class one, and 11.8% were class three . The most prevalent soft palate morphology observed in this study was the "rat tail" shape, accounting for 61.7% of all participants. This morphology was consistently the most common across all investigated skeletal classifications. The "leaf" shape followed in prevalence, representing 18.5% of the sample. The least frequent morphology, identified in only 2.5% of participants, was the "S-shaped" type. This pattern of prevalence held true within each individual skeletal pattern as well. Conclusion Rat tail shape of soft palate was by far the most common morphology while distorted soft palate or S-shaped soft palate was the rarest form of soft palate in patients. There is no relationship between the skeletal pattern of the jaw and the morphology of the soft palate in the studied population .

Data on four species of Longidorus Micoletzky, 1922 (Nematoda: Longidoridae) from southern and southeastern Iran, including description of a new species.

Four species of the genus Longidorus were recovered from southern (Bushehr province) and southeastern (Southern Khorasan province) Iran. The first species, L. paratabrizicus n. sp. represents a new member to the genus and is characterised by 4.8-5.6 mm long females with anteriorly flattened lip region separated from the rest of the body by depression, amphidial fovea pocket-shaped without lobes, tail conical, dorsally convex, ventrally almost straight with bluntly rounded tip and males in population. By having similar lip region and tail shape, the new species most closely resembles five species viz. L. artemisiae, L. globulicauda, L. patuxentensis, L. sturhani, and L. tabrizicus. It represents the cryptic form of the last species. The second species belongs to L. mirus, recovered in both southern and southeastern Iran, representing the first record of the species after its original description. As an update to the characteristics of this species, it's all juvenile developmental stages were recovered and described. The criteria to separate L. mirus from two closely related species, L. auratus and L. africanus, are discussed. The third species belongs to L. persicus, a new record in southern Iran. The fourth species, L. orientalis was recovered in high population density in association with date palm trees in Bushehr province. The phylogenetic relationships of the new species and recovered populations of L. mirus and L. persicus were reconstructed using two ribosomal markers and the resulted topologies were discussed.

Further studies on the diversity of Cylicospirura Vevers, 1922 (Nematoda: Spirocercidae) in African carnivores, with description of a new species.

Cylicospirura Vevers, 1922 is a genus of gastrointestinal spirurid nematodes parasitizing mainly felid but also canid, hyaenid and dasyurid hosts. Presently, 11 species are recognized worldwide, of which 4, Cylicospirura subaequalis, Cylicospirura felinea, Cylicospirura crocutae and Cylicospirura pardalis, have been recorded from African carnivores. In the present study, we describe Cylicospirura phiri n. sp. from hyaenas, namely Crocuta crocuta (type host) in Zimbabwe and Hyaena hyaena in Cameroon. The new species is the second species in the genus with bicuspid teeth. Furthermore, it can be distinguished from its congeners by a combination of characters, such as the absence of accessory teeth, the length and shape of the muscular oesophagus, position of the nerve ring, deirids and excretory pore in relation to the muscular oesophagus, the position of the vulva, spicule length and the shape of the female tail. Additionally, based on new material, detailed morphological descriptions are provided for C. crocutae and C. pardalis whose original descriptions were based on fragmented material. The material from Felis lybica, currently deposited as C. subaequalis, is described as C. felinea. First-time scanning electron micrographs are presented for the 4 species confirmed in African carnivores.

Bursaphelenchus glaucae n. sp. isolated from larval faeces of a longhorn beetle, Aeolesthes chrysothrix chrysothrix (Bates), in its pupal chamber constructed in the dead wood of Quercus glauca Thunb. from Japan

Summary A Bursaphelenchus species belonging to the hofmanni group (corneolus subgroup) was isolated from a small piece of larval faeces of the longhorn beetle Aeolesthes chrysothrix chrysothrix in its pupal chamber. The chamber was constructed in a dead wood section of Quercus glauca obtained from a live tree. The material was obtained during a management procedure of a garden tree to remove the dead part from live tree. The species is typologically characterised by its three-lined lateral field, the position of its secretory-excretory pore overlapping with the metacorpus anterior half, a very small spicule with distinctive broad and rounded condyles, a flattened trapezoid-shaped rostrum and small flattened cucullus, the presence of seven (P1, P2 and P3 papilliform and P5 gland) male genital papillae, a female vulva with a side flap and female tail forming an elongate conoid with a strongly ventrally curved posterior half and narrowly rounded or digitate tip. The species is typologically close to B. corneolus, sharing a small cucullus and female tail shape, but can be distinguished from the other species by the position of the secretory-excretory pore and the spicule rostrum shape. Phylogenetically, the new species forms a well-supported clade with B. corneolus, but can be distinguished by its clearly separable phylogenetic status inferred from SSU and D2-D3 LSU sequences and the difference in the ITS sequence. The new species is described as B. glaucae n. sp. Although the nematode was isolated from the larval faeces of A. c. chrysothrix, it has not been directly isolated from the insect body to date, thus, the carrier insect of the nematode has not been determined.

Optimization Design of Automotive Rear Tails for Enhancing the Downforce and Grip Effect during High Speed

Vehicle motion control and safety have always been key research directions in the field of automotive engineering. However, the traditional rear tail design has limitations in providing downforce, which cannot adequately meet the needs of high-speed driving. In this study, a computational fluid dynamics (CFD) simulation technique combined with an optimization algorithm was used to systematically investigate the influence of rear tail shape and layout on vehicle downforce. By introducing a parametric rear fin design into the CFD model and applying a multi-objective optimization algorithm, various design options can be systematically explored to improve the downforce performance. It was found that with the optimized tail fin design, the car was able to achieve higher downforce and provide better grip and stability during high speed. Specifically, downforce gains of up to 20% were observed, leading to significant improvements in vehicle handling and stability compared to conventional designs. The results of this research are not only of great significance to the field of automotive engineering but also of substantial help to improve the motion performance and safety of vehicles. optimizing the rear tail design can effectively improve the grip of the car in the process of high speed, provide a safer and more stable driving experience for the driver, and is also expected to play an important role in motorsport and other fields.

Description of Pauronemoides siddiqii n. gen., n. sp. (Tylenchomorpha, Paurodontidae), a morphological and molecular phylogenetic study

Summary Three populations of Pauronemoides siddiqii n. gen., n. sp. were recovered from three different locations in northwestern and northern Iran from bark and soil samples. The new genus was described and illustrated based upon morphological and molecular characteristics. Pauronemoides n. gen. belongs to the family Paurodontidae and is characterised by the medium-sized body, asymmetrical knobs in stylet base, stem-like extension into intestine, post-vulval uterine sac (PUS) absent or rudimentary, different tail tip shape between sexes, and bursa enveloping tail or reaching to the tail end. The type species, Pauronemoides siddiqii n. gen., n. sp., is mainly characterised by 752-1281 μm body length in females and 660-1085 μm in males, six equally-sized lips, stylet 9-11 μm long with asymmetrical knobs, six incisures in lateral fields forming five bands, three of which (two outers and one central) are wider, and variably lengthened stem-like extension projecting into the intestine. Vulva situated posteriorly (V = 87.7-91.7%), PUS absent. Conical tail with widely rounded end, having a small mucron at tip in females, males with conical tail ending to a narrower tip and bursa enveloping tail completely. The type species of the new genus was compared with all known species of the genera Prothallonema, Paurodontus, Paurodontoides and Paurodontella. Pauronemoides siddiqii n. gen., n. sp. resembles Prothallonema macrocellum and P. mucronatum by having the bulb extension penetrating into the intestine, dimorphism in tail shape of both sexes and bursa enveloping tail, and Paurodontella iranica by tail shape dimorphism between sexes and bursa ending near tail tip. Therefore, the above-mentioned species are transferred to the new genus as Pauronemoides macrocellus n. gen., n. comb. (= Prothallonema macrocellum), P. mucronatus n. gen., n. comb. (= Prothallonema mucronatum) and P. iranicus n. gen., n. comb. (= Paurodontella iranica). In addition to morphological comparisons, molecular phylogenetic analyses were performed using two sequences of small subunit (SSU), and three partial sequences of D2-D3 expansion segments of the large subunit (LSU) rDNA, and the resulting topologies were discussed.

Morphological Characterization of Kage and Baruwal Sheep (Ovis aries Linnaeus, 1758) Breeds in Nepal

Sheep farming in Nepal is closely linked to its agricultural heritage and contributes to livelihoods and the socio-economic fabric. This study synthesizes the morphological characterization of Kage and Baruwal (Ovis aries Linnaeus, 1758) sheep, highlighting their genetic and functional attributes, including body size, conformation, coat color, horn morphology, and reproductive parameters. This study synthesizes the morphological characterization of Kage and Baruwal (O. aries) sheep, highlighting their genetic and functional attributes, including body size, conformation, coat color, horn morphology, and reproductive parameters. The analysis revealed a significant difference (P ≤ 0.01**) in quantitative traits between the two breeds. The Baruwal sheep exhibited higher mean values for tail length (12.96 ± 0.47 cm), ear length (10.67±0.20 cm), neck length (21.75±0.38 cm), chest girth (67.14±0.50), height at hip bone (64.78±0.44 cm), body weight (33.04±0.65 Kg), and height below withers (67.10±0.56). Additionally, correlation analysis of different quantitative traits was found to be significant at the 0.01 level on a two-tailed test. The study's results indicate significant quantitative variations, which suggest genetic adaptations and selective pressures. The analysis of qualitative traits highlights differences in horn presence, shape, fleece, head color, neckline, and tail shape, providing insights into genetic diversity and functional adaptations. The study concludes that comprehending such phenotypic traits helps with breed management, conservation, and sustainable agriculture. The preservation of genetic diversity and adaptability is underscored by indigenous sheep breeds, which requires further research to elucidate the genetic mechanisms underlying these traits.

Identification of Candidate Genes for Red-Eyed (Albinism) Domestic Guppies Using Genomic and Transcriptomic Analyses.

Guppies are small tropical fish with brightly colored bodies and variable tail shapes. There are two phenotypes of domestic guppy eye color: red and black. The wild type is black-eyed. The main object of this study was to identify candidate genes for the red-eyed phenotype in domestic guppies. We hope to provide molecular genetic information for the development of new domestic guppy strains. Additionally, the results also contribute to basic research concerning guppies. In this study, 121 domestic guppies were used for genomic analysis (GWAS), and 44 genes were identified. Furthermore, 21 domestic guppies were used for transcriptomic analysis, and 874 differentially expressed genes (DEGs) were identified, including 357 upregulated and 517 downregulated genes. Through GO and KEGG enrichment, we identified some important terms or pathways mainly related to melanin biosynthesis and ion transport. qRT-PCR was also performed to verify the differential expression levels of four important candidate genes (TYR, OCA2, SLC45A2, and SLC24A5) between red-eyed and black-eyed guppies. Based on the results of genomic and transcriptomic analyses, we propose that OCA2 is the most important candidate gene for the red-eyed phenotype in guppies.

Exterior characteristics of male Sakub sheep in the different ages and types

This study aims to determine the exterior characteristics of male Sakub sheep with different ages and types. The study was conducted on Sakub sheep contest in the Pandansari village, Brebes. A total of 134 heads of male Sakub sheep with horns (SSWH: 95 heads) and Sakub sheep without horns (SSNH; 39 heads) were collected. Both consist of two categories of rams (aged 12 month-36 months) and young rams (aged 0-11 months). Four exterior characters (skin color-SC; horn shape-HS; tail shape-TS; face shape-FS) and 3 quantitative characteristics of the shape (body weight-BW; body length-BL; and height shoulder-HS) were scored. The descriptive analysis was used to examine the data. The result showed that ram SSWH has BW=67.23 ± 15.59 kg; BL= 75.75± 6.23 cm; HS= 75.22 ± 5.17cm. The Ram SSNH has BW =62.72 ± 14.50kg; BL = 76.11 ± 5.91cm; HS= 72.39 ± 4.54cm. Qualitative results such as CS, SH, ST and SF both of them have specifications for each other. Additionally, ram Sakub sheep with horns (SSWH) has higher score compare to SSNH for height shoulder. In young ram HS, BW and BL showing not different each other’s. The correlation value between body weight with the other measurements has a positive correlation. Qualitative results explained for us SSWH and SSNH have dominant trait. They are color of skin is white, big horn and back curved, shape of face is convex and shape of tail is long and hang straight. In conclusion, the exterior characteristics of Sakub Sheep with horn and without horn have different performances in both quantitative and qualitative traits.

STUDY OF SOFT PALATE DIMENSION AND NASOPHARYNGEAL DEPTH (NEED’S RATIO) USING LATERAL CEPHALOMETRICS X- RAY

Background: Soft palate is a tissue mass that hangs behind the hard palate mainly to seal the pharyngeal airway. The length of the soft palate should be adequate to close the pharyngeal depth. Failure to completely seal leads to velopharyngeal insufficiency while longer palatal length leads to obstructive sleep apnea. This study aimed to find the need’s ratio among the general Nepalese population. Methods: Lateral cephalograms of 591 of 17 years and above cases without any history of palatal surgery, orthodontic treatment or congenital defect were studied. The length of the soft palate, pharyngeal depth and thickness of the palatal tissue was measured using VLX computer program in lateral cephalograms obtained from gendex orthoralix 9200. The ratio of palatal length pharyngeal depth was calculated as Need’s ratio. Results: Soft palate length was 33.27 + 7.74 and 24.82 + 4.53 respectively. The Need’s ratio calculated is 0.75. The rat tail shape of soft palate was highly prevalent 173 (28.3%) while S shape was least 51 (8.6%) . Crook type of soft palate has highest Need’s ratio. Conclusions: The mean Need’s ratio of Nepalese population is 0.75. Need’s ratio also varies from shape of the soft palate.

Development of the bioinspired propulsion system for a robotic fish

Biomimetic robots aim to replicate the movement principles of living creatures, which have been continuously perfected by nature to ensure survival. Technically, survival comprises two factors: optimizing movement efficacy, such as speed, distance traveled, or acceleration, and minimizing energy consumption during movement. Researchers have made several attempts to develop a biomimetic fish robot [1–3]. Tunas are a group of fish with numerous evolutionary adaptations that make them exceptional swimmers, including tail shape, lateral peduncle keels, pectoral fin shape, and finlets. Thunniform locomotion is characterized by limited undulation, typically restricted to the rear one-third of the body, with maximal amplitude reached at the end of the tail peduncle. A bioinspired propulsion system was developed for a robotic fish model. It is based on the combination of an elastic cord with a tail fin that is firmly attached to the cord. Two symmetric movable thrusts that simulate muscle contractions connect the tail fin to a servomotor. The propulsion system provides oscillatory tail movement that can be controlled for amplitude and frequency. This movement translates to the movement of the robotic fish, which executes the thunniform principle of locomotion. The body and tail fin of the robotic fish were designed using a computational model that simulates a virtual body in water. Subsequently, we constructed a prototype of the robotic fish and tested it under experimental conditions. Experiments were conducted to investigate the relationship between the robot’s kinematics and the dynamic parameters of the propulsion system. The results showed that increasing the frequency of tail fin oscillations led to an increase in the robot’s speed. At fixed frequencies, there was an interval of energetically efficient travel speeds up to a threshold velocity. Movement at higher speeds was achievable; however, it was accompanied by greater power consumption. The conclusion aligns with the data from COT studies on living tunas, indicating qualitative agreement. However, the robot’s values were quantitatively higher. Our robotic fish reached a maximum speed of approximately 0.4 BL/s, exceeding speeds in other works where a simplified tail section was used (0.22 BL/s [4], 0.254 BL/s [5]). Our study demonstrated a correlation between the efficiency of robot swimming and amplitude, which was previously unexplored in addition to previous findings on the relationship between tail beat frequency and swimming speed, as well as the dependence of frequency and swimming speed. The results showed that increasing the oscillation amplitude of the propulsion system, at a fixed frequency, only led to a rise in swimming speed up to a certain threshold. However, further increases in amplitude resulted in minimal speed increases at higher energy costs. An evaluation of energy efficiency was conducted, assessing its dependence on dynamic parameters of tail oscillation. The results show that the transport cost rises as the tail amplitude rises beyond the threshold. Furthermore, it was found that for a fixed frequency, an interval of energetic preferred speeds up to a threshold exists. Although moving at a higher speed is possible, it consumes more power. In general, it is preferable to increase caudal fin oscillation frequency rather than amplitude to increase swimming speed. These findings are in qualitative accordance with the outcomes of the numerical simulation of thunniform swimming.

New generalized extreme value distribution with applications to extreme temperature data

AbstractA new generalization of the extreme value distribution is presented with its density function, having a wide variety of density and tail shapes for modeling extreme value data. This generalized extreme value distribution will be referred to as the odd generalized extreme value distribution. It is derived by considering the distributions of the odds of the generalized extreme value distribution. Consequently, the new distribution is enlightened by not only having all six families of extreme value distributions; Gumbel, Fréchet, Weibull, reverse‐Gumbel, reverse‐Fréchet, and reverse‐Weibull as submodels but also convenient for modeling bimodal extreme value data that are frequently found in environmental sciences. Basic properties of the distribution, including tail behavior and tail heaviness, are studied. Also, quantile‐based aliases of the new distribution are illustrated using Galton's skewness and Moor's kurtosis plane. The adequacy of the new distribution is illustrated using well‐known goodness‐of‐fit measures. A simulation is performed to validate the estimated risk measures due to repeated data points frequently found in temperature data. The Grand Rapids and well‐known Wooster temperature data sets are analyzed and compared to nine different extreme value distributions to illustrate the new distribution's bimodality, flexibility, and overall fitness.

Adaptive tails? Parallel evolution of expanded tails in monsoonal tropics lineages of an Australian gecko radiation (Oedura)

Abstract Ecological drivers of variation in the morphology of the lizard tail are understudied despite its important and varied functions in defence, locomotion, balance, climbing, and resource storage. We quantified variation in original tail shape and surface area-to-volume ratio (SA : V) in an Australian gecko clade (Oedura) and tested whether environmental variables are predictors of this variation. To use museum specimens, we developed an approach to straighten deformed preserved tails for accurate shape analysis. Tail shape varied from a relatively ‘typical lizard’ tail—long, tapered, and circular in cross-section—to a distinctive expanded, wide, and flat shape. Extreme versions of the latter shape seem to have evolved in parallel in two distantly related lineages. Wide tails and low SA : V ratio values occur in the Australian Monsoonal Tropics, while arid zone species all had a narrow, tapered tail with high SA : V. These data suggest expanded or bulbous tails may be analogous to succulence in plants and an adaptation for resource storage in environments with predictable peaks (wet season) and dearths (dry season) of resource availability. However, limited replicated evolution of bulbous tails precludes statistical significance in this case, and more analyses of tail anatomy in Oedura and other lizard clades are required to test this hypothesis further.

Fault-displacement models for aggregate and principal displacements

New fault-displacement models (FDMs) are developed for the aggregate and principal net surface displacement using the database developed by the Fault Displacement Hazard Initiative Project. An FDM for the aggregate displacement is developed, which is then partitioned into principal and distributed displacements. The model for the aggregate displacement is first formulated in the wavenumber domain to incorporate seismology-based constraints for the extrapolation of the magnitude scaling of median displacements to large-magnitude events. The results from the wavenumber-domain model are then adjusted to fit the empirical moderate-magnitude scaling (M < 7) and the shape of the displacement profile at the ends of the rupture. Segments are used in the model development to better capture the complexity of the variability of the surface-displacement profile along strike, including regions with zero displacements. For applications in which segments cannot be identified, simplified FDMs without segments are developed that treat the number, lengths, and locations of the segments as aleatory variability. The principal-displacement FDM is then developed as an adjustment to the aggregate-displacement FDM. The segmentation and the magnitude dependence of the taper length of individual segments lead to non-self-similar scaling of the median profile along the entire rupture that can have a significant impact on probabilistic fault-displacement hazard analysis (PFDHA) for sites near the ends of faults. A key feature of the new FDMs is the use of a power-normal [Formula: see text] distribution for the aleatory variability, which leads to narrower distributions of the displacement for large-magnitude earthquakes compared to the commonly used lognormal distribution. For large-magnitude earthquakes, the expected maximum displacements computed using the power-normal distribution of the FDM are consistent with the observed maximum displacements along strike, supporting the narrower shape of the upper tail of the power-normal distribution for large-magnitude events.

Analysis of the first coronagraphic multi-band observations of a sungrazing comet

Context. Between 24 and 25 December 2021 a sungrazing comet (SOHO-4341) approached the Sun, being observed by “classical” visible light (VL) coronagraphs on board the SOHO and STEREO missions, and also by the innovative Metis coronagraph on board the ESA-NASA Solar Orbiter mission in the VL and ultraviolet (UV H I Lyman-α) band. Aims. We show how VL data acquired by the Metis coronagraph can be combined with those provided by other space-based coronagraphs to reconstruct the comet orbit, but also to provide information on the dust composition from the polarized VL emission. Moreover, we show how the UV emission can be employed to measure local plasma parameters of the ambient solar wind. Methods. By using the comet positions tracked with VL Metis images (with spatial resolution that is four times better than UV), the UV images (with a time cadence that is five times faster than VL) have been coaligned to maximize the signal-to-noise ratio in the UV band. The local electron density ne was measured from the observed exponential decay of the UV Lyman-α intensity along the tail, while the solar wind speed vwind was measured from the UV Lyman-α tail inclination with respect to the cometary orbital path deprojected in 3D. Moreover, the proton kinetic temperature Tk was also obtained by the aperture angle of the UV Lyman-α tail. Results. When the comet was at an average heliocentric distance of 14.3 R⊙, the comet had a radial speed of 155 km s−1 and a tangential speed of 59 km s−1. The comet had a UV Lyman-α tail extending in the anti-solar direction over more than 1.5 R⊙. From the analysis of the tail shape in UV we obtained the local solar wind speed (vwind = 190 km s−1), electron density (ne = 1.5 × 104 cm−3), and proton temperature (Tk = 1.2 × 106 K). Moreover, theoretical analysis of the measured UV Lyman-α intensity allowed us to estimate the radius of the cometary nucleus (Rcom = 65 m) and the water outgassing rate (QH2O = 4.8 × 1028 molec s−1). Conclusions. These results show that sungrazing comets are unique “local probes” for the ambient coronal plasma, providing measurements that are not as affected by the line-of-sight integration effects as those provided by remote sensing instruments, in regions of the Heliosphere that are not explored in situ by the ongoing space missions.

Habitat salinity and source-induced variation in body shape of euryhaline long whiskers catfish (Mystus gulio)

The study was carried out to investigate the body shape variation of the Mystus gulio collected from three different salinity gradient habitats (high-salinity brackish water, low-salinity brackish water, and freshwater) and two different sources (wild and hatchery) using linear morphometric distances, landmark-based truss-networking and geometric morphometrics. A total of 436 individuals of M. gulio were collected from the high-salinity (8–15 ppt), low-salinity (2–6 ppt), and freshwater bodies (0 ppt). For wild versus hatchery sources body shape variation, 430 individuals of M. gulio were collected from various coastal rivers and hatcheries. M. gulio from different salinity gradient habitats and sources exhibited negligible sexual dimorphism. Principal component analysis (PCA) indicated that high and low salinity populations appeared to form overlapping clusters with the freshwater populations, but other multivariate analyses discriminated both populations from brackishwater habitats from the freshwater counterparts. The geometric morphometrics displayed that the body shape variation of M. gulio from salinity gradient habitats was mainly visible in the width of the dorsal-ventral part, the snout shape, the tail shape, the head region, and the eye diameter. PCA demonstrated that multivariate spaces of both the wild and captive populations overlapped each other, although many individuals of the wild population were discriminated from the culture populations. Our results showed that truss networking and geometric morphometric methods provide consistent outcomes for body shape discrimination in the M. gulio populations.