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Global evidence of rapid flash drought recovery by extreme precipitation
No full textFlash drought affects agricultural activities and water availability. However, the rate of flash drought development and termination and their controlling mechanisms remain mostly unexplored. Using climate reanalysis (ERA5) datasets, we examine the flash drought development and recovery rates in seventeen climate regions across the globe during the 1981–2020 period. In most global climate regions, flash drought recovery (25.2 percentile/pentad) is faster than its development rate (17.2 percentile/pentad). The tropical and sub-tropical humid areas, particularly eastern North America, northern South America, South Asia, Southeast Asia, and the Islands groups, are the hotspots of rapid flash drought development and faster recovery rates. In most climate regions, flash drought development and recovery rates have considerably increased during the recent two decades. Pluvial events (heavy-to-extreme precipitation) associated with increased soil moisture and decreased atmospheric aridity vapor pressure deficit are the primary driver of the rapid flash drought recovery. Globally, 10 of 17 regions showed the dominance of extreme precipitation in flash drought recovery, primarily due to an increase in the frequency of extreme precipitation. A fraction of flash droughts terminated by extreme precipitation has increased significantly across the most regions during 1981–2020. Considering the increase in flash drought frequency, development rate, and rapid termination, the compound risk of flash droughts followed by extreme precipitation and flooding has enhanced. The abrupt transition from flash drought to wet conditions makes drought and flood management more challenging, with consequences for agriculture and water resources
Coupled 3D (J ≥ 0) Time-Dependent Wave Packet Calculation for the F + H<sub>2</sub> Reaction on Accurate Ab Initio Multi-State Diabatic Potential Energy Surfaces
No full textWe had calculated adiabatic potential energy surfaces (PESs), nonadiabatic, and spin-orbit (SO) coupling terms among the lowest three electronic states (12 A’, 22A’, and 12A”) of the F + H2 system using the multireference configuration interaction (MRCI) level of theory, and the adiabatic-to-diabatic transformation equations were solved to formulate the diabatic Hamiltonian matrix for the entire region of the nuclear configuration space. The accuracy of such diabatic PESs is explored by performing scattering calculations to evaluate integral cross sections (ICSs) and rate constants. The nonadiabatic and SO effects are studied by utilizing coupled 3D time-dependent wave packet formalism with zero and nonzero total angular momentum on multiple adiabatic/diabatic surfaces calculation. We depict the convergence profiles of reaction probabilities for the reactive as well as nonreactive processes on various electronic states at different collision energies with respect to total angular momentum including all helicity quantum numbers. Finally, total ICSs are calculated as functions of collision energies for the initial rovibrational state (v = 0, j = 0) of the H2 molecule along with the temperature-dependent rate coefficient, where those quantities are compared with previous theoretical and experimental results
Modeling of Gel Controlling Membrane Filtration in Fruit Juice Processing
No full textIn this chapter, mathematical models aimed at describing the physical mass transport phenomena in the clarification of fruit juices with hollow fiber membranes in both laminar and turbulent flow regimes are presented.
The mathematical analysis was based on the first principles using the integral method of solution to compute the developing concentration boundary layer over the gel layer. The analysis was extended for batch mode of filtration, and the profiles of permeate flux were computed for different operating conditions in the predictive mode. The simulated results were also compared with the experimental data of fruit juice processing with hollow fiber membranes
Are Vision xLSTM Embedded UNet More Reliable in Medical 3D Image Segmentation?
No full textThe development of efficient segmentation strategies for medical images has evolved from its initial dependence on Convolutional Neural Networks (CNNs) to the current investigation of hybrid models that combine CNNs with Vision Transformers. There is an increasing focus on creating architectures that are both high-performance and computationally efficient, able to be deployed on remote systems with limited resources. Although transformers can capture global dependencies in the input space, they face challenges from the corresponding high computational and storage expenses involved. This paper investigates the integration of CNNs with Vision Extended Long Short-Term Memory (Vision-xLSTM)s by introducing the novel {\it \textbf{U-VixLSTM}}.
The Vision-xLSTM blocks capture temporal and global relationships within the patches, as extracted from the CNN feature maps. The convolutional feature reconstruction path upsamples the output volume from the Vision-xLSTM blocks, to produce the segmentation output. Our primary objective is to propose that Vision-xLSTM forms an appropriate backbone for medical image segmentation, offering excellent performance with reduced computational costs. The U-VixLSTM exhibits superior performance, compared to the state-of-the-art networks in the publicly available Synapse, ISIC and ACDC datasets
Improving lung nodule segmentation in thoracic CT scans through the ensemble of 3D U-Net models
No full textPurpose
The current study explores the application of 3D U-Net architectures combined with Inception and ResNet modules for precise lung nodule detection through deep learning-based segmentation technique. This investigation is motivated by the objective of developing a Computer-Aided Diagnosis (CAD) system for effective diagnosis and prognostication of lung nodules in clinical settings.
Methods
The proposed method trained four different 3D U-Net models on the retrospective dataset obtained from AIIMS Delhi. To augment the training dataset, affine transformations and intensity transforms were utilized. Preprocessing steps included CT scan voxel resampling, intensity normalization, and lung parenchyma segmentation. Model optimization utilized a hybrid loss function that combined Dice Loss and Focal Loss. The model performance of all four 3D U-Nets was evaluated patient-wise using dice coefficient and Jaccard coefficient, then averaged to obtain the average volumetric dice coefficient (DSCavg) and average Jaccard coefficient (IoUavg) on a test dataset comprising 53 CT scans. Additionally, an ensemble approach (Model-V) was utilized featuring 3D U-Net (Model-I), ResNet (Model-II), and Inception (Model-III) 3D U-Net architectures, combined with two distinct patch sizes for further investigation.
Results
The ensemble of models obtained the highest DSCavg of 0.84 ± 0.05 and IoUavg of 0.74 ± 0.06 on the test dataset, compared against individual models. It mitigated false positives, overestimations, and underestimations observed in individual U-Net models. Moreover, the ensemble of models reduced average false positives per scan in the test dataset (1.57 nodules/scan) compared to individual models (2.69–3.39 nodules/scan).
Conclusions
The suggested ensemble approach presents a strong and effective strategy for automatically detecting and delineating lung nodules, potentially aiding CAD systems in clinical settings. This approach could assist radiologists in laborious and meticulous lung nodule detection tasks in CT scans, improving lung cancer diagnosis and treatment planning
Identification of CT Features to Differentiate Pulmonary Sarcoma from Carcinoma
No full textBackground Primary lung sarcoma (PLS) differs in management protocols and prognosis from the more common primary lung carcinoma (PLC). It becomes imperative to raise a high index of suspicion on radiological and pathological features.
Purpose The aim of this study is to highlight the variable imaging appearances of PLS compared with PLC, which impacts radiologic - pathologic correlation.
Materials and Methods A retrospective observational study of 68 patients with biopsy-proven lung tumors who underwent baseline imaging at our tertiary care cancer hospital was conducted between January 2018 and March 2022. The patient details and imaging parameters of the mass on contrast-enhanced computed tomography (CECT) were recorded and analyzed for patients with PLS and compared with PLC. Follow-up imaging was available in 9/12 PLS and 52/56 PLC patients.
Results Among 12 patients with PLS, 5 patients had synovial sarcoma on histopathology. PLS was seen in patients with a mean age of 40.8 years; the mass showed a mean size of 13.2 cm, lower lobe (75%), parahilar (75%), hilar involvement (41.7%), oval shape (41.7%), circumscribed (25%) or lobulated (75%) margins, lower mean postcontrast attenuation of 57.3 HU, fissural extension (50%), calcification (50%), and no organ metastasis other than to the lung. PLC (56 patients) was seen in the elderly with a mean age of 54.8 years; the mass showed a mean size of 5.7 cm, irregular shape (83.9%), spiculated margins (73.2%), higher mean postcontrast attenuation (77.3 HU), chest wall infiltration (30.4%), and distant metastasis (58.9%) at baseline imaging. A statistically significant difference (p < 0.05) was seen between sarcoma and carcinoma in the mean age, size, site, shape, margins, postcontrast attenuation, presence of calcifications, fissural extension, and distant metastasis.
Conclusion The distinct imaging features of sarcoma help in differentiating it from carcinoma. This can also be used to corroborate with histopathology to achieve concordance and guide clinicians on further approach
Saturation throughput analysis of hybrid access mac protocol in ieee 802.11ax wlans
No full textCurrent generation wireless local area networks (WLANs) based on the IEEE 802.11ax standard employ a novel hybrid medium access control (MAC) protocol, which combines contention-based random access (UORA) and contention-free scheduled access (SA) transmissions over orthogonal resource units (RUs). We present a novel fixed-point analysis of the saturation throughput of IEEE 802.11ax that accounts for hybrid access, discrete rate adaptation, and schedulers. Our analysis captures the dynamic flow of users between UORA and SA in hybrid access. The variability in the number of users, which depends on the number of RUs allocated to UORA and the MAC contention protocol, affects the performance of the scheduler. Our approach differs from the literature, which models either UORA or SA (but not both) or assumes a fixed number of SA users. Our results verify the accuracy of the analysis despite its simplicity and reveal that the conventional approaches can overestimate the UORA and SA throughputs
Tuning the acidity and textural properties of polyethyleneimine-supported adsorbents for enhanced economical CO<sub>2</sub> capture
No full textCO2 capture using amine-based porous solids is a promising field that has received tremendous research interest. Owing to high CO2 capture performance, fast uptake kinetics and easy regeneration, CO2 capture using amine-based sorbents has extensively been studied. Herein, polyethyleneimine (PEI)-based sorbents were developed using pseudoboehmite (PSB) and gamma alumina (γ-Al2O3) as supports, represented as PEI@PSB and PEI@γ-Al2O3, respectively. The dispersion, morphology and dynamics of PEI on a porous support play key roles in the CO2 capture performance of an adsorbent. The dispersion of PEI in an adsorbent is tuned by varying the nature of acidity of the supports. The acid-base interaction between PEI and a support enhances its dispersion in the adsorbent. It was observed that PEI@PSB with enhanced Brønsted acidic sites showed excellent PEI dispersion and consequently showed superior CO2 uptake performance compared to PEI@γ-Al2O3. In situ IR analysis majorly shows the formation of ammonium carbamates and negligible carbamic acid, confirming well-dispersed PEI on the PSB support. Among the series of adsorbents, 25% PEI@PSB exhibited the highest CO2 uptake performance of 4.9 mmol CO2 per g of the sorbent. Nitrogen sorption analysis revealed that 25 wt% of PEI is the loading optimum to retain the porosity of the material, facilitating better CO2 uptake. The long-term stability and regeneration studies confirmed that the PEI@PSB adsorbent was robust and could retain a similar adsorbent capacity of up to 100 recycles. Finally, life-cycle assessment (LCA) depicted a decrease of 19-21-fold in all the environmental impact categories per ton of carbon capture with renewable energy input, indicating the potential for decarbonizing hard-to-abate industrial emissions and achieving net-zero climate targets
The host and pathogen <i>myo</i> ‐inositol‐1‐phosphate synthases are required for <i>Rhizoctonia solani</i> <scp>AG1‐IA</scp> infection in tomato
No full textThe myo-inositol-1-phosphate synthase (MIPS) catalyses the biosynthesis of myo-inositol, an important sugar that regulates various physiological and biochemical processes in plants. Here, we provide evidence that host (SlMIPS1) and pathogen (Rs_MIPS) myo-inositol-1-phosphate synthase (MIPS) genes are required for successful infection of Rhizoctonia solani, a devastating necrotrophic fungal pathogen, in tomato. Silencing of either SlMIPS1 or Rs_MIPS prevented disease, whereas an exogenous spray of myo-inositol enhanced disease severity. SlMIPS1 was upregulated upon R. solani infection, and potentially promoted source-to-sink transition, induced SWEET gene expression, and facilitated sugar availability in the infected tissues. In addition, salicylic acid (SA)-jasmonic acid homeostasis was altered and SA-mediated defence was suppressed; therefore, disease was promoted. On the other hand, silencing of SlMIPS1 limited sugar availability and induced SA-mediated defence to prevent R. solani infection. Virus-induced gene silencing of NPR1, a key gene in SA signalling, rendered SlMIPS1-silenced tomato lines susceptible to infection. These analyses suggest that induction of SA-mediated defence imparts disease tolerance in SlMIPS1-silenced tomato lines. In addition, we present evidence that SlMIPS1 and SA negatively regulate each other to modulate the defence response. SA treatment reduced SlMIPS1 expression and myo-inositol content in tomato, whereas myo-inositol treatment prevented SA-mediated defence. We emphasize that downregulation of host/pathogen MIPS can be an important strategy for controlling diseases caused by R. solani in agriculturally important crops
Seasonal plasticity in sympatric <i>Bicyclus</i> butterflies in a tropical forest where temperature does not predict rainfall
No full textWhile variation in temperature appears to be the main environmental cue for plasticity in adult traits in many species of Mycalesina, relying on temperature would result in a mismatch between adult phenotype and environment in some regions. We measured phenotypes of six species of Bicyclus butterflies (Nymphalidae: Satyrinae: Mycalesina) in a humid tropical forest with two rainy seasons per year and modest unimodal seasonal temperature variation, such that temperature does not predict rainfall and butterflies can reproduce year-round. The butterflies showed subtle temporal variation in body size and relative eyespot size, while relative androconia length was robust to temporal environmental variation. After higher temperatures, body size tended be smaller, and relative eyespot size was larger for some species-eyespot combinations. This indicates that these butterflies follow the “hotter is smaller” rule, and show developmental plasticity in eyespot size that is typical in this clade. Eyespot sizes tended to be correlated with each other, except Cu1 in B. auricruda and some eyespots that always remained very small. Androconia length was not related to eyespot size. This pattern of correlations suggests conserved cue-use and shared mechanisms for eyespot size using both temperature and rainfall-related cues, with some exceptions