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On the semi-finite vector bundles with connection over Kähler manifolds
No full textLet X be a compact connected Kähler manifold. We consider the category CEC(X) of flat holomorphic connections (E,∇E) over X satisfying the condition that the underlying holomorphic vector bundle E admits a filtration of holomorphic subbundles preserved by the connection ∇E such that the monodromy of the induced connection on each successive quotient has finite image. The category CEC(X), equipped with the neutral fiber functor that sends any object (E,∇E) to the fiber Ex0, where x0∈X is a fixed point, defines a neutral Tannakian category over C. Let ϖEC(X,x0) denote the affine group scheme corresponding to this neutral Tannakian category CEC(X). Let πEN(X,x0) be an extension of the Nori fundamental group scheme over C [8]. We show that πEN(X,x0) is a closed subgroup scheme of ϖEC(X,x0). Finally, we discuss an example illustrating that if X is not Kähler, then the natural homomorphism πEN(X,x0)⟶ϖEC(X,x0) might fail to be an embedding
Char-mander use mbackdoor! a study of cross-lingual backdoor attacks in multilingual LLMs
No full textWe explore Cross-lingual Backdoor ATtacks (X-BAT) in multilingual Large Language Models (mLLMs), revealing how backdoors inserted in one language can automatically transfer to others through shared embedding spaces. Using toxicity classification as a case study, we demonstrate that attackers can compromise multilingual systems by poisoning data in a single language, with rare tokens serving as specific effective triggers. Our findings expose a critical vulnerability in the fundamental architecture that enables cross-lingual transfer in these models. Our code and data are publicly available at this https URL
Dwelling in the Rann: embodied place-making among agariyas (salt cultivators) in the little Rann of Kutch
No full textChemically engineered multifunctional hydrogel for potential use in biomedical applications: A report on synthesis, physicochemical characterizations, and in vitro evaluation
No full textAddressing the limitations of conventional polymeric hydrogels in eradicating bacterial infection and stimulating cell activity within a biological environment presents a significant challenge. However, chemically engineered biopolymers have gained significant attention in designing advanced hydrogel-based platforms due to their flexibility, tunable properties, multiple functionalities, and ability to deliver bioactive agents. In this study, a novel biopolymer conjugate has been synthesized through simple EDC/NHS chemical functionalization methods, where bioactive spermine, a bioamine, was conjugated to the polymeric backbone of gellan gum (GG). Analytical characterization confirmed the successful synthesis of the GG-S conjugate. This conjugate was further engineered into a multifunctional, injectable hydrogel by incorporating oxidized tannic acid (oTA), forming a crosslinked 3D matrix via imine bond formation or Schiff base reaction with superior physicochemical properties. Physicochemical characterization of novel hydrogel shows the desirable injectability profile, microporous morphology, swelling rate, degradation, and drug release profile. In vitro evaluations of hydrogel (GG-S-oTA) exhibit remarkable antibacterial, antioxidant, hemocompatibility, and excellent cytocompatibility, resulting in a twofold increase in cell viability compared to controls. These attributes highlight the potential of the GG–S–oTA hydrogel platform as a multifunctional biomaterial for diverse biomedical applications, effectively addressing challenges related to infection control while also promoting environmental sustainability
DNA and graphene-based nanomaterial applications in stem cell therapeutics and regeneration
No full textMicrowave-Assisted Green Synthesis of Fluorescent Graphene Quantum Dots: Metal Sensing, Antioxidant Properties, and Biocompatibility Insights
No full textGraphene quantum dots (GQDs) are highly valued for their chemical stability, tunable size, and biocompatibility. Utilizing green chemistry, a microwave-assisted synthesis method was employed to produce water-soluble GQDs from Mangifera Indica leaf extract. This approach is efficient, cost-effective, and environmentally friendly, offering reduced reaction times, energy consumption, and uniform particle sizes, and has proven advantageous over other methods. Water-soluble GQDs were synthesized using Mangifera Indica leaf extract, which ranged less than 15 nm in diameter, confirmed by high-resolution transmission electron microscopy with a lattice spacing of 0.34 nm. The GQDs exhibited strong photoluminescence with bright red fluorescence under UV light and excitation-independent emission at 662 nm with excitation wavelengths ranging from 300 to 500 nm, achieving a quantum yield of 10.3%. A peak at 27.2˚ was recorded corresponding to the graphite's (002) plane diffraction peak. Raman spectroscopy confirmed their graphitic nature and sp2 crystallinity, with an intensity ratio of D and G peak ID/IG ratio of 1.12. Biocompatibility assays (MTT and live/dead) showed better results at lower concentrations (1 mg/ml) while higher concentrations (2 mg/ml) showed reduced efficacy. Antioxidant tests revealed increased DPPH scavenging activity with higher GQD concentrations and longer incubation times. The GQDs demonstrated excellent performance as fluorescent biosensors for Ni2⁺ (0.15 ppm) and Fe3⁺ (0.20 ppm), with high selectivity in river water samples, highlighting their potential for environmental and health applications
Eccentric extreme mass-ratio inspirals: a gateway to probe quantum gravity effects
No full textWe examine a loop quantum gravity (LQG) inspired rotating black hole, treating it as a central supermassive black hole (SMBH) in an extreme mass-ratio inspiral (EMRI) system, where an inspiralling object exhibits eccentric motion around the SMBH. With the orbital dynamics, we derive analytical expressions for the rate of change of orbital energy and angular momentum, as well as orbital evolution, and subsequently generate the gravitational waveforms. To evaluate the difference between EMRI waveforms emitted from the Kerr black hole and a spinning black hole in LQG, we compute the dephasing and mismatch using the Laser Interferometer Space Antenna (LISA) observation. Our result indicates that LISA can distinguish the modified effect of LQG with a parameter as small as 2×10-6. The constraint on a parameter in LQG using the Fisher information matrix can be obtained within a fraction error of 10-6
HyCMAx: Power-Efficient Hybrid CMOS-Memristor Based Approximate Dividers for Error-Resilient Applications
No full textApproximate computing is a promising paradigm for improving the performance parameters of electronic systems at the expense of accuracy in error-resilient tasks such as multimedia processing, image multiplication, and neural networks. While approximate circuits utilizing CMOS technology have been extensively studied, integrating approximate computing with emerging technologies like memristors offers further performance enhancements. HyCMAx investigates a hybrid CMOS-memristor approach for designing approximate circuits. In this paper, an approximate subtractor has been proposed, which was subsequently used to implement a restoring divider using the hybrid CMOS-memristor approach. HyCMAx dividers implemented in 28nm CMOS technology node gave up to 43.8% dynamic power reduction and 31.3% transistor count reduction as compared to only-CMOS implementation. Different levels of approximation were introduced in the divider to study the limits of approximation, which would give acceptable results. The proposed designs were then evaluated in the context of neural networks and image processing applications. This study highlights the potential of combining CMOS and memristor technologies to create high-performance, power-efficient approximate circuits suitable for various error-resilient computational tasks
Analysis of shear wave velocity estimation using MASW on sloping grounds
No full textApplying the multichannel analysis of surface waves (MASW) test in sloping ground conditions is of significant interest in the geotechnical investigation when estimating a subsurface shear wave velocity (Vs) profile. The soil stratification in sloping ground violates the assumption of the horizontal soil layer in the vertically heterogeneous medium and results in misinterpretation of the Vs profile in a MASW test. One of the major challenges in this context is to identify an effective frequency range that can be used to invert the dispersion curves. This study presents a methodological framework to address the issues mentioned above. The analysis involves finite element (FE) simulations for a homogeneous sloping soil model and a six-layer sloping soil model, along with the field test validation. The wavefield was recorded for the duration of 0.3 s with a sampling frequency of 4000 Hz. Spectral characteristics of the recorded wavefield, such as attenuation of Fourier amplitudes as a function of offset distance and amplification/de-amplification of the wave amplitude (through different velocity layers), were examined. Moreover, the variation of unwrapped phases and cross power spectrum (CPS) between each pair of receivers was analyzed to identify the effective frequency range of dispersion curves. Finally, the proposed approach was successfully validated using a comparison of the Vs profiles obtained from field MASW and downhole seismic tests