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A Systematic Review and Meta-Analysis of Quantum Gravity at the Planck Scale
Get PDFThe unification of general relativity and quantum mechanics remains the most profound and unresolved challenge in modern theoretical physics. This systematic review and meta-analysis examines the current state of quantum gravity research, focusing on phenomena at the Planck scale, where the predictions of existing theories are expected to break down. The review begins by articulating the fundamental conceptual and mathematical incompatibilities between Einstein's theory of a dynamic, geometric spacetime and the fixed-background framework of quantum field theory. It then provides a comprehensive analysis of the two leading theoretical programs: String Theory and Loop Quantum Gravity. String Theory is presented as a "top-down" approach aiming for a unified theory of all forces and matter, postulating that fundamental reality consists of vibrating one-dimensional strings in higher dimensions. Its successes, including the natural incorporation of gravity and a microscopic derivation of black hole entropy, are weighed against its significant challenges, notably the landscape problem and a lack of testable predictions. In contrast, Loop Quantum Gravity is examined as a "bottom-up" approach focused solely on quantizing gravity by applying quantum principles to spacetime geometry itself. Its key predictions, such as the resolution of cosmological and black hole singularities and the quantization of area and volume, are contrasted with its primary difficulty in recovering classical spacetime at macroscopic scales. A comparative synthesis of these frameworks reveals a deep methodological schism in the field. The review then explores emerging paradigms, including Causal Set Theory, Asymptotic Safety, and the concept of emergent spacetime derived from quantum information theory, which suggests that the fabric of reality may be holographic and built from quantum entanglement. Finally, the report surveys the burgeoning field of phenomenological quantum gravity, detailing future observational and experimental avenues—from cosmological probes using gravitational waves and the cosmic microwave background to laboratory-based tests with quantum sensors and atomic clocks. The analysis concludes that while a definitive theory remains elusive, the convergence of theoretical innovation and nascent experimental capabilities heralds a new, data-informed era in the quest for a quantum theory of gravity
The Combination of Fluocinolone Acetonide and Ketocaine Hydrochloride in the Conservative Management of Symptomatic Hemorrhoidal Disease: An Overview of Preclinical and Clinical Data.
Get PDFHemorrhoidal disease (HD) is a prevalent anorectal disorder that affects up to 36% of the general population. It is characterized by symptomatic enlargement and displacement of anal cushions, frequently associated with pain, bleeding, and reduced quality of life. The pathophysiology of HD includes vascular congestion, venous stasis, and vascular dilatation, promoted by increased nitric oxide activity. Inflammatory responses are considered crucial in HD, with NF-κB playing a major role. Treatment strategies for HD vary from conservative approaches to office-based and surgical interventions. Conservative therapies, such as topical agents and flavonoid-based systemic treatments, serve as the mainstay of low-grade HD management, while invasive procedures are reserved for refractory cases. Topical formulations containing fluocinolone acetonide (FLA) and ketocaine hydrochloride (KH) combine anti-inflammatory and anesthetic effects, providing rapid and sustained relief from pain, itching, and inflammation. FLA exerts potent anti-inflammatory effects by inhibiting NF-κB and induces vasoconstrictive activity by reducing nitric oxide levels, while KH provides localized analgesia by blocking sodium channels. Collectively, these agents mitigate vascular congestion, inflammation, and HD symptoms. Clinical evidence supports the efficacy of this combination in alleviating acute symptoms, reducing recurrence, and improving patient outcomes. The FLA/KH formulation provides targeted local action with minimal systemic absorption and predominantly mild and transient adverse events. Treatment with FLA/KH is an effective and well-tolerated option for managing acute HD. Furthermore, its combination with flavonoid-based supplements, which improve venous tone and reduce capillary permeability, may aid in preventing recurrence. This combined approach leverages the rapid symptom relief provided by topical agents and the long-term benefits of systemic therapies, promoting comprehensive HD management and reducing the risk of recurrence
Barriers and facilitators to integrating the friendship bench into non-communicable disease care in Malawi: A qualitative study
Get PDFComorbid depression is common among people living with non-communicable diseases (NCDs) in Malawi and is associated with reduced treatment adherence and increased NCD and depression symptom severity. This bidirectional negative relationship between NCDs and depression necessitates an appropriate intervention for addressing depression in those living with NCDs in low resource settings. To assess barriers and facilitators to implementing the Friendship Bench (FB) for depression management as part of NCD care, a convenience sample of 22 participants involved in the development, delivery, or receipt of the FB intervention were recruited for in-depth interviews from two facilities offering the FB. Participants included 12 NCD patients, 8 FB counsellors, and 2 of the original FB developers. Implementation facilitators included an understanding of emotional distress, positive patient-provider relationships, understanding the purpose and benefits of the FB, accessibility of FB, and positive collaborative relationships amongst providers. Major implementation barriers included a lack of mental health literacy among patients, providers, and institutions, a lack of acceptance of the use of mental health interventions, misinterpretations of the scope of practice of the FB counsellor, and limited institutional support for the integration of FB into NCD care. While FB is a promising intervention for addressing depressive symptoms in people with NCDs in Malawi, major implementation barriers may impact its feasibility and acceptability for this patient population. These findings can inform future research on adapting the FB for feasible and acceptable implementation for NCD patients in low resource settings
Documenting adaptations across the Accelerating Colorectal Cancer Screening and follow-up through Implementation Science research programs: methods and adaptation examples
Get PDFIntroductionAdaptations are common, expected, and often imperative for successful uptake and sustained implementation of clinical or public health programs in real-world practice settings. Understanding which adaptations have been made to evidence-based interventions and subsequent implementation strategies throughout the life cycle of a project can contextualize findings and support future scale-up of the program. Systematic documentation of adaptations is rarely conducted or reported, and little guidance exists on approaches to documenting adaptations.MethodsAccelerating Colorectal Cancer Screening and follow-up through Implementation Science (ACCSIS) is a National Cancer Institute-funded Beau Biden Cancer MoonshotSM Initiative developed to improve colorectal cancer screening, follow-up, and referral for care among underserved groups, including diverse racial and ethnic populations and people living in rural areas. Using an iterative data gathering approach—a survey, data abstraction, and data validation—we compiled information about adaptation documentation and analytic methods and intervention and implementation strategy adaptations from the eight funded ACCSIS research programs. An analytic team representing multiple ACCSIS programs reviewed, coded, and summarized the data using a rapid qualitative analytic approach.ResultsACCSIS programs varied substantially in how they defined and documented adaptations. Nine approaches were used to document adaptations; the most common were periodic reflections and review of meeting minutes and agendas. Nine analytic methods were reported to guide adaptation analysis; the most frequently mentioned were rapid qualitative methods, descriptive statistics, and mixed-methods analysis. A total of 96 adaptations were reported by the eight research programs, most of which occurred during the pre-implementation stage (68%) or were made to the program format (71%). Only 36% of the adaptations were due to the COVID-19 pandemic.ConclusionsOur multi-method, systematic approach allowed us to explore how sites document and analyze adaptations across eight ACCSIS Moonshot programs. Using a systematic approach allowed for comparisons of intervention and strategy adaptations within and across research programs and can inform the science of adaptations, while building a knowledge base of why such adaptations are needed and how they can inform implementation efforts across time. Methods described herein provide a template for similar assessment activities in other large, multi-site research initiatives
Association between food insecurity and intimate partner violence: the role of gendered asset policies
Get PDFIntimate partner violence (IPV) affects an estimated 27% of women globally, with consequences spanning mental, physical and societal well-being. Previous research identifies individual and relational risk factors for IPV, but less is known about wider structural factors. This study examines the association between food insecurity and IPV using nationally-representative data from 156 countries, exploring gendered asset policies as a potential mediator. We used nationally representative survey data on women’s experience of IPV (1993–2019) and the Food and Agriculture Organization data on moderate to severe food insecurity. Multilevel mixed-effects generalised linear models estimated the association between standardised variables for food insecurity and IPV, accounting for country-level clustering and adjusting for gross domestic product (GDP). Mediation analysis estimated the role of gendered asset policies (Women, Business and the Law Index Score). Sensitivity analyses lagged food insecurity by at least 4 years among a subset of 59 countries. We examined data from 219 country-years representing 156 countries globally across the period of 1993–2019. After controlling for national GDP, models estimated an independent cross-sectional association between food insecurity and IPV (b=0.49; 95% CI 0.37 to 0.62). Gendered asset policies mediated 18.9% of the food insecurity-IPV relationship (indirect effect 0.099 (0.044–0.155); total effect 0.526 (0.422–0.631)). In lagged analysis, food insecurity was associated with higher IPV 2 years later (b=0.78; 95% CI 0.48 to 1.06), with a similar mediation effect (21.0%). This study is among the first to harness global data to demonstrate country-level effects of food insecurity on IPV, which countries enacting more equitable asset policies were able to mitigate a substantial proportion of. Future research should prospectively pinpoint how supportive gender policies and asset ownership can amplify the benefits of food security for women’s safety and longevity
Novel species-level database of fish embryos and larvae in New York offshore waters, 2021–2023
Get PDFUnderstanding the population dynamics of fish is vital to maintaining healthy ocean ecosystems and the human communities that depend on them. However, most fish population models lack crucial information about early life stages. Even when fish embryos and larvae (collectively, ichthyoplankton) are sampled, similar morphological features make species-level visual identification difficult, especially for embryos. So, although the Northeast US continental shelf is well-studied, existing ichthyoplankton datasets generally lack species-level information on embryos. Unlike visual methods, DNA barcoding can readily discriminate between morphologically indistinguishable specimens. Thus, our dataset of 2,294 DNA barcoded fish embryos and larvae, collected near New York (USA), contributes valuable insight into local ichthyoplankton assemblages. This dataset contains 50 unique species. Most have previously been documented in our region, but one was novel: we identified an embryo of Bathyanthias mexicanus, a species not known to inhabit or spawn in the sampled area. More broadly, this dataset can be used to address questions about fish habitat across life stages and to help ensure that local fisheries are sustainably managed
Accelerating 2D Kidney Magnetic Resonance Fingerprinting Using Deep Learning Based Tissue Quantification
Get PDFBACKGROUND: Magnetic Resonance Fingerprinting (MRF) is a technique that can provide rapid quantification of multiple tissue properties. Deep learning may potentially contribute to an accelerated acquisition of MRF. PURPOSE: (1) To develop a deep learning method to accelerate the acquisition for kidney MRF; (2) to evaluate its performance in healthy subjects and patients with renal masses. STUDY TYPE: Retrospective and based on internal reference data. SUBJECTS: Development set was 36 healthy subjects and 20 patients with renal masses. The testing set: 4 healthy subjects and 16 patients. FIELD STRENGTH/SEQUENCE: 3T, Steady-State Free Precession (FISP)-based MRF. ASSESSMENT: Quantification accuracy was evaluated in healthy kidneys and renal masses using quantitative metrics including normalized root-mean-square error (NRMSE) calculated based on reference maps generated using the standard template matching approach with all acquired MRF time frames. STATISTICAL TESTS: Paired Student's t-test. p < 0.05 was considered statistically significant. RESULTS: Accurate quantification in both T1 (NRMSE = 0.025 ± 0.003) and T2 (NRMSE = 0.053 ± 0.010) maps was obtained for healthy kidney tissues with a three-fold acceleration (576 time frames, 5 s of scan time), outperforming the template matching approach (T1, NRMSE = 0.057 ± 0.015; T2, NRMSE = 0.143 ± 0.080). For renal masses with T1 and T2 values in close range of healthy kidney tissues, similar performance was achieved with a three-fold acceleration. For renal masses presenting distinct T1 or T2 values, more MRF time frames were required to provide accurate tissue quantification. No significant difference was noticed in tissue/tumor quantification between neural networks trained using only healthy subjects versus a mixed dataset with healthy subjects and patients (p > 0.05). CONCLUSION: A deep learning-based method was developed to accelerate acquisition without compromising the accuracy of relaxation time mapping using kidney MRF. These results demonstrate reliable tissue quantification with at least a two-fold acceleration for both healthy kidneys and renal masses with various subtypes and histopathological grades. EVIDENCE LEVEL: 4. TECHNICAL EFFICACY: Stage 1
Crafted experiments to evaluate feature selection methods for single-cell RNA-seq data
Get PDFWhile numerous methods have been developed for analyzing scRNA-seq data, benchmarking various methods remains challenging. There is a lack of ground truth datasets for evaluating novel gene selection and/or clustering methods. We propose the use of crafted experiments, a new approach based upon perturbing signals in a real dataset for comparing analysis methods. We demonstrate the effectiveness of crafted experiments for evaluating new univariate distribution-oriented suite of feature selection methods, called GOF. We show GOF selects features that robustly identify crafted features and perform well on real non-crafted data sets. Using varying ways of crafting, we also show the context in which each GOF method performs the best. GOF is implemented as an open-source R package and freely available under GPL-2 license at https://github.com/siyao-liu/GOF. Source code, including all functions for constructing crafted experiments and benchmarking feature selection methods, are publicly available at https://github.com/siyao-liu/CraftedExperiment
Polydrug prevalence descriptive statistics in North Carolina in June-November 2023
No full textMeasures of central tendency for substances per sample among North Carolina samples collected from June-November 2023. Includes code and data for replication. Calculated for manuscript in submission, "No judgment, no preaching” – Approaches to Harm Reduction Service Provision for People Who Use Drugs in North Carolina.
Data collected and analyzed by Opioid Data Lab @ UNC-Chapel Hill Injury Prevention Research Center. https://opioiddata.or
Carbohydrates, enzyme activities, and microbial communities across depth gradients in the western North Atlantic Ocean
Get PDFHeterotrophic bacteria process nearly half of the organic matter produced by phytoplankton in the surface ocean. Much of this organic matter consists of high-molecular-weight (HMW) biopolymers such as polysaccharides and proteins, which must initially be hydrolyzed to smaller sizes by structurally specific extracellular enzymes. Few previous studies, however, have investigated the structural complexity of polysaccharides among regions and depths. To simultaneously investigate substrate structure and microbial community composition and function, we concurrently determined carbohydrate abundance and structural complexity, bacterial community composition, and peptidase and polysaccharide hydrolase activities across depth gradients from surface to bottom water at four distinct stations in the western North Atlantic Ocean. Although the monosaccharide constituents of particulate organic matter (POM) were similar among stations, the structural complexity of POM-derived polysaccharides varied by depth and station, as demonstrated by polysaccharide-specific antibody probing. Bacterial community composition and polysaccharide hydrolase activities also varied substantially by depth, suggesting that the structure and function of bacterial communities may be related to substrate structural complexity. Thus, the extent to which bacteria can transform organic matter in the ocean is dependent on both the structural complexity of the organic matter and their enzymatic capabilities in different depths and regions of the ocean