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"Zheng, Wenxia"
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Symmetry-Aware Transformers for Asymmetric Causal Discovery in Financial Time Series
2025
Financial markets exhibit fundamental asymmetries in temporal causality, where policy interventions create asymmetric transmission patterns that traditional symmetric modeling approaches fail to capture. This work introduces a mathematical framework that exploits the inherent symmetries of transformer architectures while preserving essential asymmetric temporal relationships in financial causal inference. We develop CausalFormer, a symmetry-aware neural architecture that maintains the permutation equivariance properties of self-attention mechanisms while enforcing strict temporal asymmetry constraints for causal discovery. The framework incorporates three mathematically principled components: (1) a symmetric attention matrix construction with asymmetric temporal masking that preserves the mathematical elegance of transformer operations while ensuring causal consistency, (2) a multi-scale convolution module with symmetric kernel initialization but asymmetric temporal receptive fields that captures policy transmission effects across heterogeneous time horizons, and (3) enhanced Nelson–Siegel decomposition that maintains the symmetric factor structure while modeling the evolution dynamics of asymmetric factors. Our mathematical formulation establishes the formal symmetry properties of the attention mechanism under temporal transformations while proving asymmetric convergence behaviors in policy transmission scenarios. The integration of symmetric optimization landscapes with asymmetric causal constraints enables simultaneous achievement of mathematical elegance and economic interpretability. Comprehensive experiments on monetary policy datasets demonstrate that the symmetry-aware design achieves a 15.3% improvement in the accuracy of causal effect estimations and a 12.7% enhancement in the predictive performance compared to those for existing methods while maintaining 91.2% causal consistency scores. The framework successfully identifies asymmetric policy transmission mechanisms, revealing that monetary tightening exhibits 40% faster propagation than easing policies, establishing new mathematical insights into the temporal asymmetries in financial systems. This work demonstrates how principled exploitation of architectural symmetries combined with domain-specific asymmetric constraints opens up new directions for mathematically rigorous yet economically interpretable deep learning in financial econometrics, with broad applications spanning computational finance, economic forecasting, and policy analysis.
Journal Article
Progranulin improves neural development via the PI3K/Akt/GSK-3β pathway in the cerebellum of a VPA-induced rat model of ASD
2022
Autism spectrum disorder (ASD) is a neurodevelopmental disease featuring social interaction deficits and repetitive/stereotyped behaviours; the prevalence of this disorder has continuously increased. Progranulin (PGRN) is a neurotrophic factor that promotes neuronal survival and differentiation. However, there have not been sufficient studies investigating its effect in animal models of autism. This study investigated the effects of PGRN on autistic phenotypes in rats treated with valproic acid (VPA) and assessed the underlying molecular mechanisms. PGRN was significantly downregulated in the cerebellum at postnatal day 14 (PND14) and PND35 in VPA-exposed rats, which simultaneously showed defective social preference, increased repetitive behaviours, and uncoordinated movements. When human recombinant PGRN (r-PGRN) was injected into the cerebellum of newborn ASD model rats (PND10 and PND17), some of the behavioural defects were alleviated. r-PGRN supplementation also reduced cerebellar neuronal apoptosis and rescued synapse formation in ASD rats. Mechanistically, we confirmed that PGRN protects neurodevelopment via the PI3K/Akt/GSK-3β pathway in the cerebellum of a rat ASD model. Moreover, we found that prosaposin (PSAP) promoted the internalisation and neurotrophic activity of PGRN. These results experimentally demonstrate the therapeutic effects of PGRN on a rat model of ASD for the first time and provide a novel therapeutic strategy for autism.
Journal Article
Soft-tissue evidence for homeothermy and crypsis in a Jurassic ichthyosaur
2018
Ichthyosaurs are extinct marine reptiles that display a notable external similarity to modern toothed whales. Here we show that this resemblance is more than skin deep. We apply a multidisciplinary experimental approach to characterize the cellular and molecular composition of integumental tissues in an exceptionally preserved specimen of the Early Jurassic ichthyosaur
Stenopterygius
. Our analyses recovered still-flexible remnants of the original scaleless skin, which comprises morphologically distinct epidermal and dermal layers. These are underlain by insulating blubber that would have augmented streamlining, buoyancy and homeothermy. Additionally, we identify endogenous proteinaceous and lipid constituents, together with keratinocytes and branched melanophores that contain eumelanin pigment. Distributional variation of melanophores across the body suggests countershading, possibly enhanced by physiological adjustments of colour to enable photoprotection, concealment and/or thermoregulation. Convergence of ichthyosaurs with extant marine amniotes thus extends to the ultrastructural and molecular levels, reflecting the omnipresent constraints of their shared adaptation to pelagic life.
The presence of blubber and distribution of melanophores in a countershading pattern in an Early Jurassic ichthyosaur demonstrate that the evolutionary convergence of these reptiles with extant marine amniotes extends to the cellular and molecular levels.
Journal Article
Preservation potential of keratin in deep time
by
Sjövall, Peter
,
Schweitzer, Mary Higby
,
Zheng, Wenxia
in
Animal feathers
,
Animals
,
Antibodies
2018
Multiple fossil discoveries and taphonomic experiments have established the durability of keratin. The utility and specificity of antibodies to identify keratin peptides has also been established, both in extant feathers under varying treatment conditions, and in feathers from extinct organisms. Here, we show localization of feather-keratin antibodies to control and heat-treated feathers, testifying to the repeatability of initial data supporting the preservation potential of keratin. We then show new data at higher resolution that demonstrates the specific response of these antibodies to the feather matrix, we support the presence of protein in heat-treated feathers using ToF-SIMS, and we apply these methods to a fossil feather preserved in the unusual environment of sinter hot springs. We stress the importance of employing realistic conditions such as sediment burial when designing experiments intended as proxies for taphonomic processes occurring in the fossil record. Our data support the hypothesis that keratin, particularly the β-keratin that comprises feathers, has potential to preserve in fossil remains.
Journal Article
Implementing intelligent nursing interventions to enhance self-efficacy and hospital readiness in parents of preterm infants: a randomised controlled trial protocol
by
Lin, Zibin
,
Lin, Niyang
,
Lin, Kang
in
Artificial Intelligence
,
Breastfeeding & lactation
,
Clinical nursing
2025
IntroductionThe discharge readiness of preterm infants and parental self-efficacy are crucial for ensuring high-quality postdischarge care and positive health outcomes. However, many parents face significant challenges, including anxiety, lack of confidence and insufficient support. Research indicates that greater discharge readiness and self-efficacy enhance adherence to care plans, parenting confidence and stress management. Despite this, existing interventions often lack personalisation and real-time support to meet the evolving needs of parents. Intelligent, adaptive interventions may bridge this gap by providing tailored, data-driven guidance.Methods and analysisThis randomised controlled trial will evaluate the effectiveness of an intelligent intervention based on just-in-time adaptive interventions and the Kenner Transition Model in enhancing parental self-efficacy and discharge readiness. A total of 84 parents of preterm infants from a tertiary hospital will be randomly assigned to either a control group that receives routine discharge education or an experimental group that receives additional support through a WeChat program, which includes personalised guidance, real-time feedback and one-on-one online support. Primary outcomes include discharge readiness (measured using the Chinese version of the Readiness for Hospital Discharge Scale-Parent Form), parental self-efficacy (measured using the Chinese Parent Self-Efficacy Scale), breastfeeding rate, rehospitalisation rate and infant growth indicators (eg, body weight). Secondary outcomes include parental anxiety, caregiving ability and satisfaction with continuity of care. Data will be collected at baseline, 24 hours before discharge, and at 1 week, 1 month and 3 months after discharge. Statistical analysis will be performed using SPSS, Python, RStudio and EpiData to evaluate the effectiveness of the intervention.Ethics and disseminationThis study has been approved by the Ethics Review Committee of the First Affiliated Hospital of Shantou University (ID: SDFY-B-2024-185). Informed consent is required from all participants or their guardians. The authors intend to submit their findings for publication in peer-reviewed journals or academic conferences.Trial registration numberNCT06635473.
Journal Article
Periodontopathic Microbiota and Atherosclerosis: Roles of TLR-Mediated Inflammation Response
by
Zheng, Wenxia
,
Deng, Yiting
,
Zhang, Miaoyu
in
Atherosclerosis
,
Bacteria
,
Cerebrovascular disease
2022
Atherosclerosis is a chronic inflammatory disease with a high prevalence worldwide, contributing to a series of adverse cardiovascular and cerebrovascular diseases. Periodontal disease induced by pathogenic periodontal microbiota has been well established as an independent factor of atherosclerosis. Periodontal microorganisms have been detected in atherosclerotic plaques. The high-risk microbiota dwelling in the subgingival pocket can stimulate local and systematic host immune responses and inflammatory cascade reactions through various signaling pathways, resulting in the development and progression of atherosclerosis. One often-discussed pathway is the Toll-like receptor-nuclear factor-κB (TLR-NF-κB) signaling pathway that plays a central role in the transduction of inflammatory mediators and the release of proinflammatory cytokines. This narrative review is aimed at summarizing and updating the latest literature on the association between periodontopathic microbiota and atherosclerosis and providing possible therapeutic ideas for clinicians regarding atherosclerosis prevention and treatment.
Journal Article
Chemistry supports the identification of gender-specific reproductive tissue in Tyrannosaurus rex
2016
Medullary bone (MB), an estrogen-dependent reproductive tissue present in extant gravid birds, is texturally, histologically and compositionally distinct from other bone types. Phylogenetic proximity led to the proposal that MB would be present in non-avian dinosaurs and recent studies have used microscopic, morphological and regional homologies to identify this reproductive tissue in both theropod and ornithischian dinosaurs. Here, we capitalize on the unique chemical and histological fingerprint of MB in birds to characterize, at the molecular level, MB in the non-avian theropod
Tyrannosaurus rex
(MOR 1125) and show that the retention of original molecular components in fossils allows deeper physiological and evolutionary questions to be addressed.
Journal Article
Environmental Factors Affecting Feather Taphonomy
by
Zheng, Wenxia
,
Equall, Nancy
,
Schweitzer, Mary Higby
in
Animal feathers
,
Biodegradation
,
Carbon dioxide
2022
The exceptional preservation of feathers in the fossil record has led to a better understanding of both phylogeny and evolution. Here we address factors that may have contributed to the preservation of feathers in ancient organisms using experimental taphonomy. We show that the atmospheres of the Mesozoic, known to be elevated in both CO2 and with temperatures above present levels, may have contributed to the preservation of these soft tissues by facilitating rapid precipitation of hydroxy- or carbonate hydroxyapatite, thus outpacing natural degradative processes. Data also support that that microbial degradation was enhanced in elevated CO2, but mineral deposition was also enhanced, contributing to preservation by stabilizing the organic components of feathers.
Journal Article
Keratin Durability Has Implications for the Fossil Record: Results from a 10 Year Feather Degradation Experiment
by
Zheng, Wenxia
,
Schweitzer, Mary H.
,
Moyer, Alison E.
in
Animal feathers
,
Animals
,
Antibodies - chemistry
2016
Keratinous 'soft tissue' structures (i.e. epidermally derived and originally non-biomineralized), include feathers, skin, claws, beaks, and hair. Despite their relatively common occurrence in the fossil record (second only to bone and teeth), few studies have addressed natural degradation processes that must occur in all organic material, including those keratinous structures that are incorporated into the rock record as fossils. Because feathers have high preservation potential and strong phylogenetic signal, in the current study we examine feathers subjected to different burial environments for a duration of ~10 years, using transmission electron microscopy (TEM) and in situ immunofluorescence (IF). We use morphology and persistence of specific immunoreactivity as indicators of preservation at the molecular and microstructural levels. We show that feather keratin is durable, demonstrates structural and microstructural integrity, and retains epitopes suitable for specific antibody recognition in even the harshest conditions. These data support the hypothesis that keratin antibody reactivity can be used to identify the nature and composition of epidermal structures in the rock record, and to address evolutionary questions by distinguishing between alpha- (widely distributed) and beta- (limited to sauropsids) keratin.
Journal Article
Testing the Hypothesis of Biofilm as a Source for Soft Tissue and Cell-Like Structures Preserved in Dinosaur Bone
by
Zheng, Wenxia
,
Schweitzer, Mary Higby
,
Moyer, Alison E.
in
Animals
,
Bacillus cereus - physiology
,
Bioaccumulation
2016
Recovery of still-soft tissue structures, including blood vessels and osteocytes, from dinosaur bone after demineralization was reported in 2005 and in subsequent publications. Despite multiple lines of evidence supporting an endogenous source, it was proposed that these structures arose from contamination from biofilm-forming organisms. To test the hypothesis that soft tissue structures result from microbial invasion of the fossil bone, we used two different biofilm-forming microorganisms to inoculate modern bone fragments from which organic components had been removed. We show fundamental morphological, chemical and textural differences between the resultant biofilm structures and those derived from dinosaur bone. The data do not support the hypothesis that biofilm-forming microorganisms are the source of these structures.
Journal Article