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The present study compares a single‐band chorus wave against a banded chorus wave observed by Van Allen Probes at adjacent times, and demonstrates that the single‐band chorus wave is associated with an anisotropic electron population over a broad energy range, while the banded chorus wave is accompanied by an electron phase space density plateau and an electron anisotropy reduction around Landau resonant energies. We further compare banded chorus waves with different spectral gap widths, and show that a wider spectral gap is associated with electron isotropization extending to higher energies with respect to the equatorial Landau resonant energy. We suggest that early generated chorus waves isotropize electrons via Landau resonant acceleration, and the waves that propagate to higher latitudes isotropize electrons at higher energies. The isotropization extending to higher energies leads to a larger spectral gap of new chorus waves after electrons bounce back to the equator. Plain Language Summary: Naturally occurring chorus waves in the Earth's magnetosphere typically consist of two frequency bands. The present study aims to explain what controls the bandwidth of the chorus frequency gap that separates chorus waves into two bands. We first compare a single‐band chorus wave against a banded chorus wave observed by a Van Allen Probe satellite at adjacent times. The banded chorus wave is accompanied by an electron phase space density plateau and an electron anisotropy reduction due to Landau resonance, while this phenomenon is not clearly seen in association with the single‐band chorus wave. We further compare banded chorus waves with different gap widths. Satellite observations indicate that a wider frequency gap is associated with electron isotropization extending to higher energies. We suggest that Landau resonant acceleration extending to high latitudes isotropizes electron distribution at high energies, leading to new chorus waves with a large frequency gap. In contrast, Landau resonance that stops at a relatively lower latitude (due to waves being damped) leads to new chorus waves with a smaller frequency gap. Key Points: Freshly injected anisotropic electron population without a PSD plateau generates single band chorus wavesBanded chorus waves are more common because electrons usually have already undergone isotropization at Landau resonant energies along the drift pathLandau acceleration extending to higher energies occurring at higher latitudes leads to more pronounced electron isotropization and larger chorus spectral gaps [ABSTRACT FROM AUTHOR]

Purpose Setting Design Methods Results Conclusions To report the 2‐year efficacy and safety of penetrating canaloplasty versus ab externo canaloplasty for the treatment of primary open‐angle glaucoma (POAG).A single surgical site in China.This was a prospective, randomized controlled trial. POAG patients were randomly assigned to the penetrating canaloplasty or ab externo canaloplasty group.This study enrolled POAG patients who underwent penetrating canaloplasty or ab externo canaloplasty randomly. Surgical success, intraocular pressure (IOP), number of glaucoma medications, and surgical complications were evaluated until 24 months post‐operatively. Surgical success was defined as 6 mmHg ≤ IOP ≤21 mmHg with an IOP reduction ≥20%, which included qualified success (with or without medications) and complete success (without medications).A total of 52 eyes (45 patients) were randomly assigned to one of two groups: the penetrating canaloplasty group (PCP, n = 26) or the ab externo canaloplasty group (CP, n = 26). The probabilities of qualified success and complete success were 92.3% and 76.9%, respectively, in the PCP group and 64.1% and 52.1%, respectively, in the CP group at 24 months (p = 0.013, p = 0.042, log‐rank test). The mean IOP decreased from 30.8 ± 10.7 and 28.6 ± 11.8 mmHg to 14.1 ± 3.3 mmHg in the PCP group and 22.1 ± 13.6 mmHg in the CP group at year two (p = 0.007). The PCP group also received fewer medications (0.2 ± 0.5) than did the CP group (0.7 ± 1.2) at year two (p = 0.038). Post‐operative complications were similar, and the most common complications were transient IOP elevation and hyphema in the PCP group (42.3%, 46.2%) and the CP group (38.5%, 23.1%) (p > 0.05).Compared to ab externo canaloplasty, penetrating canaloplasty had a greater surgical success rate and better IOP reduction with a comparable rate of complications. [ABSTRACT FROM AUTHOR]

Circular synthetic aperture radar (CSAR) has attracted a lot of interest, recently, for its excellent performance in civilian and military applications. However, in CSAR imaging, the result is to be defocused when the height of an object deviates from a reference height. Existing approaches for this problem rely on digital elevation models (DEMs) for error compensation. It is difficult and costly to collect DEM using specific equipment, while the inversion of DEM based on echo is computationally intensive, and the accuracy of results is unsatisfactory. Inspired by multi-focus image fusion in optical images, a spatial-domain fusion method is proposed based on the sum of modified Laplacian (SML) and guided filter. After obtaining CSAR images in a stack of different reference heights, an all-in-focus image can be computed by the proposed method. First, the SMLs of all source images are calculated. Second, take the rule of selecting the maximum value of SML pixel by pixel to acquire initial decision maps. Secondly, a guided filter is utilized to correct the initial decision maps. Finally, fuse the source images and decision maps to obtain the result. A comparative experiment has been processed to verify the exceptional performance of the proposed method. The final processing result of real-measured CSAR data demonstrated that the proposed method is effective and practical. [ABSTRACT FROM AUTHOR]

Background: Gastric cancer (GC) is the fourth leading cause of cancer‐related death worldwide. Minichromsome maintenance proteins family member 8 (MCM8) assists DNA repair and DNA replication. MCM8 exerts tumor promotor function in multiple digestive system tumors. MCM8 is also considered as a potential cancer therapeutic target. Methods: Bioinformatics methods were used to analyze MCM8 expression and clinicopathological significance. MCM8 expression was detected by immunohistochemistry (IHC) staining and qRT‐PCR. MCM8 functions in GC cell were explored by Celigo cell counting, colony formation, wound‐healing, transwell, and annexin V‐APC staining assays. The target of MCM8 was determined by human gene expression profile microarray. Human phospho‐kinase array kit evaluated changes in key proteins after ribosomal protein S15A (RPS15A) knockdown. MCM8 functions were reassessed in xenograft mouse model. IHC detected related proteins expression in mouse tumor sections. Results: MCM8 was significantly upregulated and predicted poor prognosis in GC. High expression of MCM8 was positively correlated with lymph node positive (p < 0.001), grade (p < 0.05), AJCC Stage (p < 0.001), pathologic T (p < 0.01), and pathologic N (p < 0.001). MCM8 knockdown inhibited proliferation, migration, and invasion while promoting apoptosis. RPS15A expression decreased significantly after MCM8 knockdown. It was also the only candidate target, which ranked among the top 10 downregulated differentially expressed genes (DEGs) in sh‐MCM8 group. RPS15A was identified as the target of MCM8 in GC. MCM8/RPS15A promoted phosphorylation of P38α, LYN, and p70S6K. Moreover, MCM8 knockdown inhibited tumor growth, RPS15A expression, and phosphorylation of P38α, LYN, and p70S6K in vivo. Conclusions: MCM8 is an oncogene and predicts poor prognosis in GC. MCM8/RPS15A facilitates GC progression. [ABSTRACT FROM AUTHOR]

Simple Summary: Rumination behavior is a crucial indicator of cattle health and welfare. The timely monitoring and analysis of this behavior can provide valuable insights into the physiological status of the animals. Distinguishing from manual observation and wearable devices, this study proposes a method using video technology for monitoring cattle rumination behavior. This method aims to track physiological indicators during rumination, including chewing count, rumination duration, and chewing frequency. This approach can help livestock managers promptly understand the health status of cattle. Furthermore, this research method offers a new perspective for the construction of smart farming, providing technical support for the intelligent transformation of the livestock industry. Cattle rumination behavior is strongly correlated with its health. Current methods often rely on manual observation or wearable devices to monitor ruminating behavior. However, the manual monitoring of cattle rumination is labor-intensive, and wearable devices often harm animals. Therefore, this study proposes a non-contact method for monitoring cattle rumination behavior, utilizing an improved YOLOv8-pose keypoint detection algorithm combined with multi-condition threshold peak detection to automatically identify chewing counts. First, we tracked and recorded the cattle's rumination behavior to build a dataset. Next, we used the improved model to capture keypoint information on the cattle. By constructing the rumination motion curve from the keypoint information and applying multi-condition threshold peak detection, we counted the chewing instances. Finally, we designed a comprehensive cattle rumination detection framework to track various rumination indicators, including chewing counts, rumination duration, and chewing frequency. In keypoint detection, our modified YOLOv8-pose achieved a 96% mAP, an improvement of 2.8%, with precision and recall increasing by 4.5% and 4.2%, enabling the more accurate capture of keypoint information. For rumination analysis, we tested ten video clips and compared the results with actual data. The experimental results showed an average chewing count error of 5.6% and a standard error of 2.23%, verifying the feasibility and effectiveness of using keypoint detection technology to analyze cattle rumination behavior. These physiological indicators of rumination behavior allow for the quicker detection of abnormalities in cattle's rumination activities, helping managers make informed decisions. Ultimately, the proposed method not only accurately monitors cattle rumination behavior but also provides technical support for precision management in animal husbandry, promoting the development of modern livestock farming. [ABSTRACT FROM AUTHOR]

The ring current is an important component of the Earth's near‐space environment, as its variations are the direct driver of geomagnetic storms that can disrupt power grids, satellite communications, and navigation systems, thereby impacting a wide range of technological and human activities. Oxygen ions (O+) are one of the major components of the ring current and play a significant role in both the enhancement and depletion of the ring current during geomagnetic storms. Although a standard statistical study can provide average global distributions of ring current ions, it can't offer insight into the short‐term dynamic variations of the global distribution. Therefore, we employed the Artificial Neural Network technique to construct a global ring current O+ ion model based on the Van Allen Probes observations. Through optimization of the combination of input geomagnetic indices and their respective time history lengths, the model can well reproduce the spatiotemporal variation of the oxygen ion flux distributions and demonstrates remarkable accuracy and minimal errors. Additionally, the model effectively reconstructs the temporal variation of ring current O+ ions for non‐training set data. Furthermore, the model provides a comprehensive and dynamic representation of global ring current O+ ion distribution. It accurately captures the dynamics of O+ ions during a geomagnetic storm with the oxygen ion fluxes enhancement and decay, and reveals distinct characteristics for different energy levels, such as injection from the plasma sheet, outflow from the ionosphere, and magnetic local time asymmetry. Plain Language Summary: The ring current, a significant part of Earth's space environment, is closely linked to geomagnetic disturbances that can disrupt power grids, satellite communications, and navigation systems, affecting our daily lives. Oxygen ions (O+) are a key component of the ring current during geomagnetic active time. In our study, we use a powerful tool called Artificial Neural Networks to create a model for ring current O+ behavior. This model only requires F10.7 and geomagnetic indices as inputs. By carefully selecting the best combination of the geomagnetic indices and their time history, we built a model that can accurately mimic the behavior of oxygen ions observed by satellites. Our model demonstrates that the levels of O+ ion fluxes rise and fall at various locations during geomagnetic disturbance, which is consistent with previous observational trend. The model also helps us to understand the global distribution of O+ ions in real time. During a test case of a geomagnetic storm, the model revealed details about energy‐dependent O+ ion flux enhancement and decay. Key Points: An artificial neural network model was built to reconstruct ring current oxygen ions using geomagnetic indices as inputThe model shows high accuracy in predicting non‐training set data and successfully captures the enhancement and decay of oxygen ion fluxesThe model successfully reproduces the variation of global distribution for oxygen ions of different energies during geomagnetic storms [ABSTRACT FROM AUTHOR]

Polyurethane (PU) is a traditional chemical known for its chemical stability and mechanical performance. Inspired by the similarity between the formation and breakage of chemical coordination bonds and the energy storage and release of muscle fibers, muscle‐like electrostatically spun fibers with acid‐responsive energy storage and release were prepared by introducing bio‐inspired elastic energy storage groups and bio‐active degradation groups (PU‐BPY‐Fe) in the main chain of PU, taking advantage of the good mechanical properties of PU. The fabricated electrospinning film PU‐BPY‐Fe can respond to external stimulation, which generated high strain (32 MPa), stretch of 206%, outperforming the nanofiber membrane before stimulation, similar and even higher than the biological muscles. The variable mechanical properties and elastic energy storage capacity of PU‐BPY‐Fe were attributed to the reversible hydrogen bonding and the destabilization of metal coordination bonds (Fe3+ to Fe2+) within the material under acidic stimulation. Cytotoxicity testing of the synthesized fibers indicated a degree of biocompatibility, suggesting potential for in vivo applications. This method of storing and releasing elastic energy was demonstrated and has endowed the PU‐BPY‐Fe with stimuli‐responsibility and muscle‐like mechanical properties, which may inspire the design of soft muscles materials for robots and tissue engineering applications. [ABSTRACT FROM AUTHOR]

This article studies deep unsupervised hashing, which has attracted increasing attention in large-scale image retrieval. The majority of recent approaches usually reconstruct semantic similarity information, which then guides the hash code learning. However, they still fail to achieve satisfactory performance in reality for two reasons. On the one hand, without accurate supervised information, these methods usually fail to produce independent and robust hash codes with semantics information well preserved, which may hinder effective image retrieval. On the other hand, due to discrete constraints, how to effectively optimize the hashing network in an end-to-end manner with small quantization errors remains a problem. To address these difficulties, we propose a novel unsupervised hashing method called HARR to learn discriminative and high-quality hash codes. To comprehensively explore semantic similarity structure, HARR adopts the Winner-Take-All hash to model the similarity structure. Then similarity-preserving hash codes are learned under the reliable guidance of the reconstructed similarity structure. Additionally, we improve the quality of hash codes by a bit correlation reduction module, which forces the cross-correlation matrix between a batch of hash codes under different augmentations to approach the identity matrix. In this way, the generated hash bits are expected to be invariant to disturbances with minimal redundancy, which can be further interpreted as an instantiation of the information bottleneck principle. Finally, for effective hashing network training, we minimize the cosine distances between real-value network outputs and their binary codes for small quantization errors. Extensive experiments demonstrate the effectiveness of our proposed HARR. [ABSTRACT FROM AUTHOR]

Multifunctional metasurfaces have demonstrated extensive potential in various fields. During the design of metasurfaces, optimization of components for polarization, amplitude distribution, phase distribution, and other factors is necessary. This process typically demands expert involvement and is time‐consuming. In this paper, a metasurface inverse design method is introduced that combines a high‐precision ultra‐wideband spectrum forward prediction utilizing a neural network and a genetic algorithm. A neural network is constructed and trained to accurately predict the amplitude and phase of a 16 × 16 discrete grid structure with high degrees of freedom in the frequency range of 0.5–2 THz. Leveraging the neural network's ultra‐fast spectrum prediction capabilities (producing approximately 1000 spectra per second), the average optimization time for a single component is reduced to 1.5 min. Finally, the effectiveness of this inverse design method is validated through the design and simulation of multifunctional reflective deflection metasurfaces with two sets of 3‐bit frequency multiplexing and polarization multiplexing. The proposed metasurface inverse design method offers a new approach for the rapid design of components in complex application scenarios and holds significant reference value for metasurface designers. [ABSTRACT FROM AUTHOR]

The present study uncovers the fine structures of magnetosonic waves by investigating the EFW waveforms measured by Van Allen Probes. We show that each harmonic of the magnetosonic wave may consist of a series of elementary rising‐tone emissions, implying a nonlinear mechanism for the wave generation. By investigating an elementary rising‐tone magnetosonic wave that spans a wide frequency range, we show that the frequency sweep rate is likely proportional to the wave frequency. We studied compound rising‐tone magnetosonic waves, and found that they typically consist of multiple harmonics in the source region, and may gradually become continuous in frequency as they propagate away from source. Both elementary and compound rising‐tone magnetosonic waves last for ∼1 min which is close to the bounce period of the ring proton distribution, but their relation is not fully understood. Plain Language Summary: Naturally occurring magnetosonic waves are a kind of electromagnetic wave in the Earth's magnetized space. Their frequency spectra typically exhibit a harmonic structure. Sometimes they exhibit a rising‐tone feature, that is, the wave starts at a low pitch and gradually increases its frequency to a high pitch. Using the high‐resolution data measured by Van Allen Probe satellites, the present study uncovers that each harmonic of a magnetosonic wave may have a fine structure: they consist of a series of elementary rising‐tone emissions. The traditionally known rising‐tone magnetosonic waves consist of multiple harmonics, and we name them "compound rising‐tone magnetosonic waves". The compound rising‐tone waves may gradually become continuous in spectrum as they propagate away from source. These findings give new insights to the generation of magnetosonic waves and their impact on space environment. Key Points: Each harmonic of a magnetosonic wave may consist of a series of elementary rising‐tone emissionsThe frequency sweep rate of elementary magnetosonic waves is likely proportional to the frequencyCompound rising‐tone magnetosonic waves consist of harmonics at the source, and gradually develop a continuous spectrum during propagation [ABSTRACT FROM AUTHOR]

The fluid ferroelectrics, called ferroelectric nematics (NF), have recently become available by incorporating strong polarity into rod-shaped liquid crystal molecules. Its unprecedented electro-optic properties have created significant excitement in soft matter research. The further progression from the NF phase to the antiferroelectric smectic Z (SmZA) phase, and ultimately to the ferroelectric Smectic A (SmAF) phase, represents a remarkable journey in emerging polar liquid crystal states. Nevertheless, the limitation of NF liquid crystal materials remains one of the prominent obstacles to physical property optimization and optoelectronic device development. In this work, we synthesized a series of fluorinated liquid crystal molecules with large dipole moments and systematically investigated their phase behavior. We designed them with a similar fluorinated aromatic skeleton and varied the structures of the terminal group and bridging bond. We found that the dipole moment density and shape anisotropy significantly affect the phase behavior. Notably, diverse polar liquid crystal phases, including NF, SmZA, and SmAF were observed. Through a multi-component mixing strategy, we successfully achieved a much-expanded temperature window and improved low-temperature stability not only in the NF phase but also in the SmZA and SmAF phases. [ABSTRACT FROM AUTHOR]

The discovery of polar liquid crystals, such as ferroelectric and helielectric liquid crystals, provides fascinating platforms for designing and modulating polarisation structures that generate strong second harmonic generation. Here, we report that the helielectric nematics, i.e. the polar cholesteric liquid crystals, realise an unprecedented phase-matching condition for the second harmonic generation in the photonic bandgap. Like the circular dichroism in the linear optical regime, the phase-matched second harmonic generation generated in a helielectric nematic medium exhibits a circular polarisation selectivity in the nonlinear optical regime. The maximum g-factor for the second harmonic generation is over ~ 1.95. [ABSTRACT FROM AUTHOR]

This article discusses the importance of multi-sensor imaging and fusion technology in various fields such as medical imaging, engineering construction, and object detection. It presents different research studies related to multi-sensor imaging and fusion, including methods for imaging detection, feature extraction, and fusion, as well as objective evaluation methods. The research results demonstrate the effectiveness and potential applications of multi-sensor imaging and fusion technology in different areas. The document also provides a summary of various research topics related to the specific applications of multi-sensor technology in engineering problems, such as metal corrosion depth estimation, tunnel management, sentiment analysis, highway vehicle speed detection, road surface detection, and brainstem hematoma puncture and drainage surgery. The authors hope that this research will inspire further advancements in multi-sensor imaging and fusion. [Extracted from the article]

Probiotics and synbiotics can mitigate the negative health consequences of early-life antibiotic exposure. This study aimed to determine whether supplementation with Bifidobacterium longum ssp. infantis 79 (B79) or synbiotics composed of B79 and 2'-fucosyllactose (2'-FL) could mitigate the negative impact of ceftriaxone exposure in early-life. We found that antibiotic-treated mice exhibited lower body weight, crypt depth, short-chain fatty acid content, and α-diversity indices at weaning, while they increased the relative abundance of opportunistic pathogens (such as Enterococcus and Staphylococcus) and decreased the relative abundance of intestinal commensal bacteria. Supplementation with B79 and 2'-FL revived these antibiotic-induced negative effects and reduced the mRNA expression of IL-6, IL-12p40, and TNF-α in the spleen at weaning. Moreover, B79 and 2'-FL supplementation persistently improved crypt depth, propionic acid synthesis, and IgG and sIgA production and revived the gut microbiota structure and composition in adulthood. In conclusion, our study suggests that early-life supplementation with B79 alone or in combination with 2'-FL can mitigate ceftriaxone-induced negative effects on the gut microbiota and intestinal and immune development of mice, and these improvements can partially last into adulthood., (© 2025, The Authors. Published by Elsevier Inc. on behalf of the American Dairy Science Association®. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).)

Glioblastoma multiforme (GBM) is the most frequent primary brain malignancy in adults. Despite improvements in imaging and therapy, the prognosis remains poor. To evaluate and compare the impact of combining bevacizumab with temozolomide and radiotherapy on progression-free survival (PFS) and overall survival (OS) in patients diagnosed with GBM. A comprehensive search was conducted across multiple databases, including PubMed, Embase, Scopus, and The Cochrane Library, covering the period from their inception to December 2022. The collected data underwent analysis employing appropriate statistical methods. Six articles were included in this systematic review and meta-analysis. The addition of bevacizumab to the combination of temozolomide/radiotherapy did not increase the OS in GBM patients. The pooled odds ratio (OR) was 0.843 (95% CI: 0.615-1.156, P = 0.290). The addition of bevacizumab to radiotherapy/temozolomide did not increase the PFS in patients with GBM. The pooled OR was 0.829 (95% CI: 0.561-1.224, P = 0.346). The funnel plot demonstrated the absence of the alleged pleiotropic effects by showing no evidence of observable variability across the estimations. This study does not support the benefit of the addition of bevacizumab to temozolomide and radiotherapy in improving OS and PFS in GBM patients., (Copyright © 2024 Copyright: © 2024 Neurology India, Neurological Society of India.)

Despite the fact that there is a remarkable achievement on multifocus image fusion, most of the existing methods only generate a low-resolution image if the given source images suffer from low resolution. Obviously, a naive strategy is to independently conduct image fusion and image super-resolution. However, this two-step approach would inevitably introduce and enlarge artifacts in the final result if the result from the first step meets artifacts. To address this problem, in this article, we propose a novel method to simultaneously achieve image fusion and super-resolution in one framework, avoiding step-by-step processing of fusion and super-resolution. Since a small receptive field can discriminate the focusing characteristics of pixels in detailed regions, while a large receptive field is more robust to pixels in smooth regions, a subnetwork is first proposed to compute the affinity of features under different types of receptive fields, efficiently increasing the discriminability of focused pixels. Simultaneously, in order to prevent from distortion, a gradient embedding-based super-resolution subnetwork is also proposed, in which the features from the shallow layer, the deep layer, and the gradient map are jointly taken into account, allowing us to get an upsampled image with high resolution. Compared with the existing methods, which implemented fusion and super-resolution independently, our proposed method directly achieves these two tasks in a parallel way, avoiding artifacts caused by the inferior output of image fusion or super-resolution. Experiments conducted on the real-world dataset substantiate the superiority of our proposed method compared with state of the arts.

Objective: To compare the differences in gut microbiome composition between children with good neurodevelopment and those with delayed neurodevelopment, and to analyze the relationship between gut microbiome and the neurodevelopment status of infants in early life., Methods: The mothers were included at the Second West China Hospital from November 2020 to April 2021. Their infant stools were collected on day 0 and day 90 after birth, and the follow-up questionnaires at the corresponding time points were completed. Additionally, the Ages and Stages Questionnaires-Third Edition(ASQ-3) were completed by mothers at 12 months of age. The structure and diversity of gut microbiota were examined by 16S rRNA sequencing, and the relationship between gut microbiome and ASQ-3 questionnaire scores in early life was analyzed., Results: According to the ASQ-3 scores, mothers and infants into neurodevelopment good group(G group, n=18) and neurodevelopmental delay group(D group, n=10). Compared with the D group, the relative abundance of the Firmicutes was significantly higher in the G group at day 0(P&lt;0.05), while the level of the Proteobacteria was lower(P&lt;0.05). At day 90 after birth, the relative abundance of the Actinobacteria, Bifidobacteriaceae and Enterococcaceae was significantly higher in the G group(P&lt;0.05). In addition, alpha diversity was not statistically different between the two groups. Spearman&apos;s correlation analysis showed that Clostridiaceae of the postnatal day 0 infants was positively correlated with the communication domain score, but negatively associated with gross motor domain score in children at 12 months of age, whereas the relative abundance of Proteobacteria and Enterobacteriaceae of children at postnatal day 90 was negatively associated with communication development, while the relative abundance of Erysipelatoclostridiaceae showed a negative correlation with gross motor domain scores., Conclusion: The structure of the gut microbiome in early life between neurodevelopment good and delayed infants, and were associated with the development of communication and gross motor domain in infants at 12 months of age, suggesting that gut microbiome in early life may be related to the level of neurodevelopment in infants.

Learned 360° image compression methods using equirectangular projection (ERP) often confront a non-uniform sampling issue, inherent to sphere-to-rectangle projection. While uniformly or nearly uniformly sampling representations, along with their corresponding convolution operations, have been proposed to mitigate this issue, these methods often concentrate solely on uniform sampling rates, thus neglecting the content of the image. In this paper, we urge that different contents within 360° images have varying significance and advocate for the adoption of a content-adaptive parametric representation in 360° image compression, which takes into account both the content and sampling rate. We first introduce the parametric pseudocylindrical representation and corresponding convolution operation, upon which we build a learned 360° image codec. Then, we model the hyperparameter of the representation as the output of a network, derived from the image's content and its spherical coordinates. We treat the optimization of hyperparameters for different 360° images as distinct compression tasks and propose a meta-learning algorithm to jointly optimize the codec and the metaknowledge, i.e., the hyperparameter estimation network. A significant challenge is the lack of a direct derivative from the compression loss to the hyperparameter network. To address this, we present a novel method to relax the rate-distortion loss as a function of the hyperparameters, enabling gradient-based optimization of the metaknowledge. Experimental results on omnidirectional images demonstrate that our method achieves state-of-the-art performance and superior visual quality.