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Impacts of irrigation expansion on moist-heat stress based on IRRMIP results
No full textIrrigation rapidly expanded during the 20th century, affecting climate via water, energy, and biogeochemical changes. Previous assessments of these effects predominantly relied on a single Earth System Model, and therefore suffered from structural model uncertainties. Here we quantify the impacts ofhistorical irrigation expansion on climate by analysing simulation results from six Earth system models participating in the Irrigation Model Intercomparison Project (IRRMIP). Results show that irrigation expansion causes a rapid increase in irrigation waterwithdrawal, which leads to less frequent 2-meter airtemperature heat extremes across heavily irrigated areas (≥4 times less likely). However, due to the irrigation-induced increase in air humidity, the cooling effect of irrigation expansion on moist-heat stress is less pronounced or even reversed, depending on the heat stress metric. In summary, this study indicatesthat irrigation deployment is not an efficient adaptation measure to escalating human heat stress under climate change, calling for carefully dealing with the increased exposure of local people to moist-heat stress
Distributed energy balance, mass balance and climate sensitivity of upper Chandra Basin glaciers, western Himalaya
No full textGlacier and snow melt are the primary sources of water for streams, and rivers in upper Indus region of the western Himalaya. However, the magnitude of runoff from this glacierized basin is expected to vary with the available energy in the catchment. Here, we used a physically based energy balance model to estimate the surface energy and surface mass balance (SMB) of the upper Chandra Basin glaciers for 7 hydrological years from 2015 to 2022. A strong seasonality is observed, with net radiation being the dominant energy flux in the summer, while latent and sensible heat flux dominated in the winter. The estimated mean annual SMB of the upper Chandra Basin glaciers is −0.51 ± 0.28 m w.e. a−1, with a cumulative SMB of −3.54 m w.e during 7 years from 2015 to 2022. We find that the geographical factors like aspect, slope, size and elevation of the glacier contribute towards the spatial variability of SMB within the study region. The findings reveal that a 42% increase in precipitation is necessary to counteract the additional mass loss resulting from a 1°C increase in air temperature for the upper Chandra Basin glaciers
Shape and word parts combine linearly in the Bouba–Kiki effect
No full textLanguages have evolved in part due to cross-modal associations between shape and sound. A famous example is the Bouba–Kiki effect, wherein humans associate words like bouba/kiki to round/angular shapes. How does the Bouba–Kiki effect work for natural words and shapes that contain a mixture of features? If the effect is holistic, the effect for a composite stimulus would not be explainable using the parts. If the effect is compositional, it will be. Here we provide evidence for the latter possibility. In Experiments 1 and 2, we standardized bouba-like and kiki-like shapes and words for use in subsequent experiments. In Experiments 3-5, we created composite shapes/words by combining bouba-like and kiki-like parts. In all experiments, the Bouba–Kiki effect strength for composite shapes/words was predicted remarkably well as a linear sum of the contributions of the constituent parts. Our results greatly simplify our understanding of the Bouba–Kiki effect, leaving little room for holism
An area-bounce exchanging bijection on a large subset of Dyck paths
No full textIt is a longstanding open problem to find a bijection exchanging area and bounce statistics on Dyck paths. We settle this problem for an exponentially large subset of Dyck paths via an explicit bijection. Moreover, we prove that this bijection is natural by showing that it maps what we call bounce-minimal paths to area-minimal paths. As a consequence of the proof ideas, we show combinatorially that a path with area a and bounce b exists if and only if a path with area b and bounce a exists. We finally show that the number of distinct values of the sum of the area and bounce statistics is the number of nonzero coefficients in Johnson’s q-Bell polynomial
Development of bulk wave EMAT sensors with enhanced Lorentz force through magnetic field concentration in eddy current regions
No full textIn this paper, we propose the development of electromagnetic acoustic transducers (EMATs) to generate ultrasonic bulk waves and inspect metallic specimens at elevated temperatures. EMATs play a vital role in the NDE due to their non-contact inspection behavior; however, they are constrained by their low Signal-to-Noise Ratio (SNR), especially under high-temperature conditions. This work addresses the challenges by developing EMAT configurations that enhance the Lorentz force and ultrasonic wave generation by optimizing the magnetic field in the region of eddy current generation. The Finite Element (FE) simulations were performed in aluminum samples to study the eddy current through varying coil widths, liftoffs, and static magnetic field intensity concentration. The FE simulations on eddy current revealed that eddy current intensity is independent of the coil widths. Different EMAT configurations were designed and developed by concentrating the static magnetic field intensity in the region of the eddy current generation by considering the simulation results. Various EMAT configurations were fabricated and tested on 26 mm and 50 mm aluminum samples to measure their SNR. The configuration with the highest SNR was further tested at elevated temperatures under proper insulation techniques. These advancements have the potential to enhance the capabilities of NDE techniques in challenging industrial environments
Defect identification using sampling and outlier analysis in passive guided wave structural health monitoring
No full textPassive Structural Health Monitoring (SHM) systems face a challenge in achieving control over the propagating noise field, thereby limiting their application towards defect identification and localization. To overcome this, an outlier statistical technique based on cross-correlation is developed and implemented here to achieve defect detection under passive loading. The proposed technique is first demonstrated using simulation and then validated using an experimental setup based on an air blower as the noise source imposing on an aluminium plate. The results clearly demonstrate the feasibility of defect detection using the sparse sampling-based outlier analysis in a passive SHM system that can effectively assess the structural health integrity of infrastructures deployed under harsh environmental conditions
Using optical tweezer electrophoresis to investigate clay nanoplatelet adsorption on Latex microspheres in aqueous media
No full textThe adsorption of charged clay nanoplatelets plays an important role in stabilizing emulsions by forming a barrier around the emulsion droplets and preventing coalescence. In this work, the adsorption of charged clay nanoplatelets on a preformed Latex microsphere in an aqueous medium is investigated at high temporal resolution using optical tweezer-based single-colloid electrophoresis. Above a critical clay concentration, charged clay nanoplatelets in an aqueous medium self-assemble gradually to form gel-like networks that become denser with increasing medium salinity. In a previous publication [R. Biswas et. al., Soft Matter, 2023, 19, 24007–2416], some of us had demonstrated that a Latex microsphere, optically trapped in a clay gel medium, is expected to attach to the network strands of the gel. In the present contribution, we show that for different ionic conditions of the suspending medium, the adsorption of clay nanoplatelets increases the effective surface charge on an optically trapped Latex microsphere while also enhancing the drag experienced by the latter. Besides the ubiquitous contribution of non-electrostatic dispersion forces in driving the adsorption process, we demonstrate the presence of an electrostatically-driven adsorption mechanism when the microsphere was optically trapped in a clay gel. These observations are qualitatively verified via cryogenic field emission scanning electron microscopy and are useful in achieving colloidal stabilisation, for example, during the preparation of clay-armoured Latex particles in Pickering emulsion polymerisation
Mitochondrial topoisomerases, nucleoid architecture and mtDNA repair in human disease
No full textDNA topoisomerases are essential for maintaining DNA topology, gene expression and the accurate transmission of genetic information. Mitochondria possess circular DNA (mtDNA), which, unlike nuclear chromosomes, lacks protective histones and exists in nucleoprotein complexes called nucleoids, which are vital for mtDNA stability. Although the mitochondrial genome encodes essential genes involved in ATP production via oxidative phosphorylation, it does not encode crucial mtDNA maintenance genes and depends entirely on nuclear-encoded proteins for mtDNA maintenance. These include nuclear-encoded topoisomerases (i.e. Top1mt, Top2α, Top2β and Top3α), which alleviate topological stress during mtDNA transcription and replication, and mitochondrial transcription factor A (TFAM), are crucial for ensuring proper nucleoid structure and mtDNA packaging. Furthermore, tyrosyl-DNA phosphodiesterase 1 and 2 (TDP1 and TDP2) participate in the repair of mtDNA damage associated with trapped topoisomerase–mtDNA complexes, which can compromise mtDNA integrity and contribute to neurodegeneration, cancer and premature aging. Drugs that stabilize these protein–DNA adducts (PDAs) to induce mtDNA damage and mitochondrial dysfunction are promising new strategies for cancer therapy. This Review explores the essential roles of mitochondrial topoisomerases, overviews mechanisms involved in mtDNA repair and discusses how mitochondrial fission and mitophagy are employed as a survival strategy for clearing damaged mtDNA
(Un)Explained EMIC Waves: Understanding Quiet Time EMIC Wave Drivers
No full textElectromagnetic ion cyclotron (EMIC) waves are known to be generated through cyclotron resonance with the local ion particle population and grow when there is a large enough temperature anisotropy. In general, these temperature anisotropies necessary for wave growth are found to be associated with either solar wind pressure pulses or particle injections during geomagnetic storms or substorms. However, some EMIC events do not show any clear association with these known drivers and appear unexplained. In our analysis of high-amplitude (>1 nT) non-storm time EMIC waves, we find that 24 out of the 223 (
11%) EMIC events with peak amplitude greater than 1 nT were not found to be associated with any clear EMIC wave driver. This raises a compelling question: What magnetospheric or solar wind driver provides the free energy to grow these quiet-time EMIC waves? Here, we examine two EMIC events on 13 April 2017 and 13 February 2014, which were excited during extremely quiet solar wind and geomagnetic conditions. An in-depth analysis of field and particle measurements from multiple data sets, including ground and in situ data for these two events, indicates that extremely weak and otherwise insignificant pressure values and/or very weak substorm injections occurring multiple hours before the event play a significant role in quiet time wave generation
The Surface Energy Balance of a Himalayan Mature Pine (<i>Pinus roxburghii</i>) Ecosystem During Drought Stress Conditions
No full textThis study presents the energy balance dynamics of a mature Pine (Pinus roxburghii) ecosystem of the Indian Himalaya using multiple year (March 2020 to December 2022) eddy covariance-based measurements. Efforts are made to quantify the inter-annual dynamics of surface energy balance at seasonal and annual time scales. The impact of drought conditions, induced by soil moisture and vapor pressure deficit, on energy partitioning of the ecosystem is quantified using Bowen ratio (β) and evaporative fraction (EF). The energy balance closure is assessed for three seasons (i.e., pre-monsoon, monsoon, and post-monsoon) of each observation year. We find that the closure fraction (CF) of the site is more than 80% on an annual scale. Higher CF is observed during pre-monsoon (⁓80%) and monsoon (⁓90%) seasons due to the onset and duration of the growing season. The available energy partitioned into latent heat flux is larger than the sensible heat flux for the ecosystem, signifying that evapotranspiration is one of the dominant components of water and energy budgets. The evaporative cooling at the site takes place during the monsoon season through higher EF; however, the Pine ecosystems sustained the dry pre-monsoon season with higher β values. We find that the soil moisture-induced drought at the site resulted in higher partitioning of the available energy to sensible heat flux, effectively promoting the drought stress condition. However, it is to be noted that a better comprehension could be made for Pine forest behavior under environmental stress if such studies are further replicated