bluuebunny/crossref_metadata_2025_split huggingface dataset:
Strong turbulent flow in the sub-auroral region in the Antarctic can deteriorate satellite-based navigation signals
Authors: Kotova Daria , Sinevich Aleksandr , Chernyshov Alexander , Chugunin Dmitrii , Jin Yaqi , Miloch Wojciech 
Published: October 2024

Abstract

In the subauroral zone at the boundary of the auroral oval in the evening and night hours during geomagnetic disturbances, a narrow (about 1º-2º) and extended structure (several hours in longitude) is formed. It is known as a polarization jet (PJ) or the sub-auroral ion drift (SAID). The PJ/SAID is a fast westward ion drift and is one of the main signatures of a geomagnetic disturbance in the subauroral ionosphere at the altitudes of the F-layer, when the geomagnetic AE index reaches more than 500 nT. Plasma speed in the PJ/SAID can reach several kilometres per second, and the size of plasma irregularities inside it can reach scales from tens of meters to several hundred meters. Such high velocities and structured plasma can affect trans-ionospheric radio signals and lead to scintillations in the received signal. We show that at the moment of auroral activity intensification, an increase in the magnitude of phase scintillation index (σϕ) as well as loss of satellite signals lock were observed in the region of the PJ/SAID equatorward of the auroral oval over Dronning Maud Land (Queen Maud Land) in Antarctica. We find that fluctuations inside the PJ/SAID can lead to serious deterioration of radio communication or navigational services. We emphasize the importance of considering the geometry of the beam passing from the GNSS satellite to the receiver on the ground. We highlight the mutual contribution of the PJ/SAID and the diffuse aurora boundary, which are almost impossible to separate in practice. Our results demonstrate the importance of considering the subauroral zone, where very dynamic plasma formations can occur with a strong flow and various-scale irregularities inside that lead to serious interference in satellite communications.
Preparation of ZnAl layered double hydroxides supported by silica for the treatment of Cr(VI) and Cu(II) in aqueous solution
Authors: Zhang Fengrong , Liu Luxing , Zhang Cuilan , Shang Dawei , Wu Lishun 
Published: October 2024

Abstract

A novel adsorbent (ZA/SiO2) was prepared by blending urea mixture of ZnSO4 and Al2(SO4)3 while using SiO2 as a support form. The adsorption properties of ZA/SiO2 for the removal of toxic metal ions (Cu(II) and Cr(VI))from water were evaluated. By batch experiment method to investigate the ZA/SiO2 adsorption of Cu(II) and Cr(VI) solution treatment effect. The sorption kinetics curves of Cu(II) and Cr(VI) on ZA/SiO2 were L-shaped. What's more, the solid concentration effect was found in the process of sorption kinetics. Langmuir and Freundlich sorption isotherm models were used to analyze the adsorption data. The results showed that the adsorption conforms to Langmuir and Freundlich adsorption isotherm models. However, the adsorption capacity of ZA/SiO2 compounds for Cu(II) and Cr(VI) is greatly improved. The adsorption capacity of Cu(II) is 158 mg·g− 1 and of Cr(VI) is 176 mg·g− 1, which were 3.6 and 1.8 times of ZA, respectively. Density functional theory (DFT) was utilized for the analysis of intrinsic mechanism and specific pathways. It primarily involved isomorphic substitution of Cr(VI) and Zn(II) and the intercalation of Cr2O72−, with the exception of Cr(OH)3 precipitation. Conversely, Cu(II) removal's primary mechanism in water was isomorphic substitution, except for Cu(OH)2 precipitation.
Cathinone from Khat (Catha edulis) Leaves Induces Testicular Dysfunction in Male Vervet Monkeys through Dose-dependent Regulation of Testicular Steroidogenesis-associated Genes and Hormone Synthesis
Authors: Nyongesa Albert Wafula , Muge Edward , Nyaboga Evans 
Published: October 2024

Abstract

Background Consumption of fresh khat (Catha edulis Forssk.) leaves has been shown to affect reproductive health, especially with regards to impaired male reproductive function. (-)-cathinone, the principal alkaloid in khat plant is known for its euphoric and psychostimulatory effects. Additionally, high dose and chronicity of exposure to khat extract and (-)-cathinone has been associated with impaired reproductive hormone synthesis in experimental animal models. It is currently not known whether the expression of genes encoding for specific testicular enzymes along sex steroid biosynthetic pathway are involved in this impairment. The present study aimed to examine the effects of (-)-cathinone from fresh khat leaves on mRNA expression of steroidogenesis-associated genes (3b hydroxy steroid dehydrogenase [3b-HSD] type I and 17b hydroxy- steroid dehydrogenase [17b-HSD] type I) and intra-testicular hormone production in vervet monkey testis.
Methods Eight male animals were divided into 4 groups, with treatment subjects being administered (-)-cathinone at 0.8, 3.2 and 6.4 mg/kg body weight, respectively while control group was administered normal saline. The mRNA expression of steroidogenesis-associated genes using semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) and real-time quantitative RT-PCR as well as ex vivo studies for measurement of intracellular progesterone, androstenedione and testosterone levels of interstitial cells were investigated.
Results Results showed that (-)-cathinone at 3.2 and 6.4 mg/kg body weight (medium and high doses, respectively) significantly (P< 0.05) increased mRNA expression of 3b-HSD type I and 17b- HSD type I compared to the control group whereas the changes in 3b-HSD type I and 17b- HSD type I expression were not significant for (-)-cathinone at 0.8 mg/kg body weight. There was an increased intra-testicular progesterone, androstenedione and testosterone in cultured interstitial cells exposed to luteinizing hormone but which was significantly suppressed when co-treated with (-)-cathinone at 100 µl of 6.4 mg/kg body weight.
Conclusion In conclusion, the results demonstrated that (-)-cathinone at high doses has the potential to affect steroidogenesis and thus directly or indirectly influence spermatogenic processes and general reproductive function in the habitual male (-)-cathinone/khat user.
A Replicating RNA Vaccine confers Durable Immunity against Lethal Crimean Congo Hemorrhagic Fever Virus Challenge in Mice
Authors: Leventhal Shanna S , Shaia Carl , Rao Deepashri , Lewis Matthew , Meade-White Kimberly , Erasmus Jesse H. , Feldmann Heinz , Hawman David W 
Published: October 2024

Abstract

Spread by Hyalomma genus ticks, Crimean-Congo Hemorrhagic Fever Virus (CCHFV) causes a severe hemorrhagic disease endemic throughout Southern and Eastern Europe, Asia, and Africa. To date, there are no widely approved vaccines for CCHFV and treatment for disease is largely supportive. Due to this lack of intervention, the WHO lists CCHFV as a high priority pathogen. Recently, we described a highly efficacious self-replicating RNA vaccine which is protective against CCHFV disease in mice and non-human primates (NHP). This vaccine induces high titers of non-neutralizing anti-nucleoprotein antibodies and a robust T-cell response against the viral glycoprotein. Here, we assess the durability of this vaccine in mice by monitoring the immunogenicity and efficacy of this vaccine up to one year post vaccination. We found that while GPC-specific T-cell responses and anti-NP antibody titers waned over time, mice remained protected against lethal CCHFV challenge for at least one year post vaccination.
Estimation on Groundwater Drawdown Due to Subsurface Horizontal Drains for Large- scale Landslides
Authors: Lin Der-Guey , Huang Yu-Po , Chen I-Hui 
Published: October 2024

Abstract

This study performed a series of steady state drainage analyses under a constant groundwater recharge rate and drawdown for the subsurface drainage of horizontal drains in a large-scale landslide area using 3D numerical and empirical methods. The changes in groundwater level drawdown determined by the numerical method are similar to those calculated using past empirical methods. A normalized groundwater recharge rate is the most crucial parameter which dominates the drawdown pattern of groundwater levels. The recharge rate is related to the spacing of horizontal drains and the boundary constant groundwater head at upper slope. The higher spacing of horizontal drains results in higher values of the area and volumetric flow rate of draining influence for a single horizontal drain. Also, there are more significant groundwater flow-through effects in the higher spacing between two adjacent horizontal drains. Nevertheless, the horizontal drains could discharge a larger drainage intensity to keep a safe depth of groundwater drawdown with a smaller spacing and installed at a permeable layer of large-scale landslide. Finally, the 3D numerical method is more computational efficiency for the influence range of drainage field and the geometric curve of groundwater drawdown using simulation analysis of complex geological conditions and horizontal drains.
Evolving Drought Dynamics in Barcelona: Leveraging a Bayesian Ensemble Algorithm for Insightful Analysis and a Bidirectional Long Short-Term Memory Network for Predictive Modeling
Authors: Granata Francesco , Nunno Fabio Di 
Published: October 2024

Abstract

In recent times, the growing influence of climate change has emphasized the significance of examining hydrological patterns for efficient planning and management of water resources. This study proposes an investigation of the Standard Precipitation Index (SPI) trends and abrupt changes, at time scales of 12 and 24 months, for the municipality of Barcelona, Spain. The overall trend of SPI was assessed based on the seasonal Mann-Kendall (MK) test. The severity and duration of drought events, considering the entire time series and twenty-year intervals from 1820–1840 to 2000–2020, were also evaluated. Then, the Bayesian Changepoint Detection and Time Series Decomposition (BEAST) algorithm was employed to identify abrupt changes in trend along the SPI time series. The seasonal MK analysis reveals a rising trend, indicating a positive shift in precipitation patterns over time. On the other hand, the BEAST analysis presents a more intricate scenario, where recent decades demonstrate a simultaneous presence of short-term positive shifts alongside prolonged negative trends, indicating a shift toward drought conditions. Furthermore, the effectiveness of a Bi-LSTM-based model in forecasting the SPI with a temporal horizon of up to 6 months was evaluated. The forecasting model displayed a decline in performance as the forecasting horizon extended, with the most precise predictions achieved for a 1-month lead time, with R2 up to 0.899 for SPI-24.
Comparative Analysis of the Nutrient Composition of Caulerpa lentillifera from Various Cultivation Sites
Authors: Zhou Wenchuan , Wang Yun , Xu Rui , Tian Jialin , Li Ting , Chen Suwen 
Published: October 2024

Abstract

The nutrient, amino acid and fatty acid compositions of Caulerpa lentillifera from various aquaculture regions were assessed to analyze their nutritional characteristics and potential for aquaculture development. The nutrient composition of C. lentillifera was determined according to standard national nutrient determination methods, and the following data were revealed. 1) The basic nutritional components of C. lentillifera were relatively more abundant in the three aquaculture areas in Guangdong Province. The crude protein content was significantly greater in C. lentillifera from the Dapeng and Daya areas of Guangdong Province than those from the Beihai, Dongshan and Nha Trang areas (P < 0.05). Additionally, the crude lipid content of C. lentillifera from the Daya population was significantly greater than those in the samples from the Beihai, Dongshan, and Nha Trang areas (P < 0.05). Furthermore, the total sugar contents in the Daya and Shanwei populations were significantly greater (P < 0.05) than those in the other four populations. 2) The total amino acid (TAA) content of C. lentillifera ranged from 7.05–12.37%, with notable concentrations of the fresh amino acids aspartic acid (Asp) and glutamic acid (Glu). Significant variations in the TAA and essential amino acid (EAA) levels were observed among the cultivation regions (P < 0.05), with the Shanwei population exhibiting the highest TAA content of 12.37% and EAA content of 4.65%, surpassing all other populations except for Guangdong Province (P < 0.05). 3) The fatty acid composition analysis revealed that the total fatty acid (TFA) and unsaturated fatty acid (UFA) levels in the long-stemmed grape fern alga from Daya were 2.400% and 1.048%, respectively, and significantly greater than those in the other populations except for Dapeng (P < 0.05). These results imply that the nutritional quality of the Daya population of C. lentillifera is relatively high.
Adaptive Robust Sensorless Control for PMSM Based on Super-Twisting Algorithm Back EMF Observer and Extended State Observer
Authors: Sun Hongbo , Zhang Xiaoyu , Liu Xiangbin , Xiong Shuiping 
Published: October 2024

Abstract

The estimation of the back electromotive force (EMF) signal of the permanent magnet synchronous motor (PMSM) using sliding mode observer (SMO) has a large number of high-frequency chattering, which cannot be directly applied to the sensorless control system of PMSM. This article proposes a robust sensorless control scheme based on an improved back EMF observer (BEO) and an extended state observer (ESO). First, a super-twisting algorithm back EMF observer (STABEO) is proposed by combining the back EMF model and the super twisting algorithm, in which the equivalent signal of the back EMF is estimated through the traditional SMO. The STABEO takes into account the uncertainty and unmodelled dynamics in the back EMF model, which leads to smaller chattering, better estimation, and faster convergence. Then, an ESO is constructed to calculate the rotor position, the rotor speed, and the total interference, and after that, a robust speed controller is designed. In addition, the stability is proved through the Lyapunov stability theory. Finally, the effectiveness and feasibility of the proposed control scheme were verified through experiments. The proposed robust sensorless control scheme has the characteristics of strong anti-interference ability, faster convergence, smaller high-frequency chattering, and without losing its robustness.
Tackling deforestation with deep-learning-based cattle counts on satellite images
Authors: Hodel Leonie , Wegner Jan , Garnot Vivien Sainte Fare , Rocha-Gomes Francisco , Valentim Judson , Garrett Rachael 
Published: October 2024

Abstract

Cattle ranching and linked tropical deforestation remain intractable global sustainability challenges with large implications for climate security and rural wellbeing. Despite the large area devoted to cattle in the tropics, cattle numbers have hitherto been estimated by downscaling from course data or limited to sparse case studies. In this study, we estimate cattle numbers using deep learning and 30 cm resolution satellite imagery, focusing on the case of the Brazilian Amazon. Our cattle dataset covering a total of 12’100 km2 is integrated with land cover maps and property-level data to assess cattle density. The analysis reveals low cattle intensity of 0.5-0.9 animals per hectare across Amazonian states, with lower intensity on properties with higher recent deforestation. Promisingly, we find evidence that combined policies for conservation (zero-deforestation commitments) and intensification (low carbon agriculture incentives) are linked to cattle intensification. Our method opens new avenues for monitoring and researching cattle practices.
Mapping of catecholaminergic denervation, neurodegeneration, and inflammation in 6-OHDA-treated Parkinson's disease mice
Authors: Santoro Matteo , Lam Rachel K. , Blumenfeld Sarah E. , Tan Weiqi , Ciari Peter , Chu Emily K. , Saw Nay L. , Rijsketic Daniel Ryskamp , Lin Jennifer S. , Heifets Boris D. , Shamloo Mehrdad 
Published: October 2024

Abstract

Efforts to develop disease-modifying treatments for Parkinson's disease (PD) have been hindered by the lack of animal models replicating all hallmarks of PD and the insufficient attention to extra-nigrostriatal regions pathologically critical for the prodromal appearance of non-motor symptoms. Among PD models, 6-hydroxydopamine (6-OHDA) infusion in mice has gained prominence since 2012, primarily focusing on the nigrostriatal region. This study characterized widespread tyrosine hydroxylase-positive neuron and fiber loss across the brain following a unilateral 6-OHDA (20 µg) infusion into the dorsal striatum. Our analysis integrates immunolabeling, brain clearing (iDISCO+), light sheet microscopy, and computational methods, including fMRI and machine learning tools. We also examined sex differences, disease progression, neuroinflammatory responses, and pro-apoptotic signaling in nigrostriatal regions of C57BL/6 mice exposed to varying 6-OHDA dosages (5, 10, or 20 µg). This comprehensive, spatiotemporal analysis of 6-OHDA-induced pathology may guide the future design of experimental PD studies and neurotherapeutic development.
Tris and Trehalose based modified cryopreservation dilutor in block freezing improves cryo-survivability and functionality of Sahiwal bull semen
Authors: Sethi Manisha , Mohanty Tushar Kumar , Shah Nadeem , Bhakat Mukesh , Swain Dilip Kumar , Yadav Dileep Kumar , Kumar Nishant , Baithalu Rubina Kumari 
Published: October 2024

Abstract

Our study aimed to enhance cryoprotection and improve post-thaw sperm quality by using a new freezing protocolthat combines trehalose and glycerol.The semen ejaculate from each bull was collected and split into three aliquots.Split one was the control group (C), in which semen was extended in a tris fructose egg yolk glycerol (TFEG) extender and underwent the conventional freezing protocol.In split two (T1) and split three (T2) groups, the semen was diluted in tris fructose egg yolk extender containing 25% trehalose, with glycerol 5% in both groups. Split two (T1) underwent conventional freezing, whereas split three (T2) underwent aluminium block freezing.After freezing-thawing, the progressive sperm motility,viability, acrosome integrity, sperm velocity and path parameters were significantly (p ≤ 0.05) improved in T2 among groups. Additionally, the degree of oxidative stress was substantially lower in T2 among groups.The present study's findings revealed the promising role of trehalose (25%) and glycerol (5%) in tris-based extender in achieving aluminium block freezing, as it significantly improved the post-thaw sperm survivability, and this method can suitably be used for quality frozen semen production.
Immobilization of Bacillus-Derived Pectinase on Agarose Beads for Improved Catalytic Performance
Authors: Rehman Haneef Ur , Aziz Shanaz , Shamim Haleema , Rahim Mir Chakar , Ali Wajid , Bahram Sana 
Published: October 2024

Abstract

Pectinase catalyzes the depolymerization of pectin polymer into galacturonic acid and is utilized in various industrial applications. In the current study, pectinase from Bacillus species was encapsulated in agarose beads using the entrapment technique to enhance its operational stability against harsh industrial processes. The impact of agarose concentrations on pectinase encapsulation was investigated and the highest immobilization yield (89%) was achieved at 1.5% of agarose concentration. Agarose bead encapsulation increased the optimal temperature activity of pectinase from 45°C to 50°C, and the reaction time extended from 5 to 15 minutes compared to the soluble enzyme. The optimum pH of pectinase was increased after encapsulation and the encapsulated pectinase showed maximum activity at pH 8.0 as compared to pH 7.0 for free pectinase. The Km value of pectinase slightly changed from 1.12 to 1.32, and the Vmax decreased from 12200 to 9400 µM/min after encapsulation. The encapsulated pectinase retained complete activity after 120 hours at both 30°C and 40°C. Additionally, the encapsulated pectinase maintained its initial activity through 10 cycles and retained more than 70% of its activity after 10 cycles.
Unravelling water anomalies using a percolation approach
Authors: Hasmy Anwar , Hehlen Bernard , Paredes Ricardo 
Published: October 2024

Abstract

Water’s density maximum at 277 K and compressibility peak at 228 K, among other anomalies, arise from competing low- and high-density molecular populations[1]. However, linking water anomalies to phase separation is challenging without a theoretical framework that relates these phenomena to the underlying structural and thermodynamic changes[1,2]. Here, using a realistic water model and percolation approach, we show that these anomalies outline phase separation stages upon cooling. At maximum density temperature, a cluster of low-density connected populations emerges and percolates, coexisting within a dominant high-density connected network. In deep supercooling, the scale-invariant percolation quantities of the low- and high-density liquid networks exhibit a crossover at the peak compressibility temperature, sharing similar structures. Cooling further, the high-density liquid network collapses near the density minimum, yielding total dominance to the low-density phase. These trends persist across the pressure-temperature range where maximum density and Widom lines extend to positive pressures[3]. Below the hypothetical liquid-liquid critical point[4,5], the emanating spinodal, identifying the metastable limit of a compressed low-density liquid, align with its percolation limit, emphasising the close connection between percolation and spinodal decomposition[6]. The results show that phase separation occurs when the density increases sharply with rising pressure or temperature. Integrating our findings with insights from percolation studies on supercritical water [7,8], and metallic and oxide glasses[9,10], highlights the broad applicability of the percolation approach to unveil anomalies in pure substances.
Promising climate progress: How close do net-zero ambitions take us towards the Paris Agreement goals?
Authors: Tagomori Isabela S. , Diuana Fabio , Baptista Luiz Bernardo , Bertram Christoph , Dafnomilis Ioannis , Drouet Laurent , Fosse Florian , Fragkiadakis Dimitris , Fricko Oliver , Hooijschuur Elena , Iyer Gokul , Kikstra Jarmo , Krey Volker , Luderer Gunnar , Ou Yang , Reis Lara Aleluia , Richters Oliver , Rochedo Pedro , Vrontisi Zoi , Weitzel Matthias , Zwerling Matthew , Ruijven Bastiaan van , Schaeffer Roberto , Vuuren Detlef van 
Published: October 2024

Abstract

The Paris Agreement aims to limit the increase of global mean temperature to well-below 2°C and preferably 1.5°C. This study provides a multi-model analysis of global projections of current policies and pledges, and climate pathways to implement the Paris Agreement’s overall goals. In this exercise, current policies and NDCs scenarios are updated. Additionally, three main scenarios are analysed: i) a long-term strategies (LTS) scenario, which assumes the full implementation of the NDCs and the announced net-zero pledges from COP26 (in Glasgow, 2021); ii) an Expanded LTS scenario, which expands the net-zero pledges to all countries/regions; and iii) an Accelerated LTS scenario, which sees climate targets being brought forward by 5–10 years. Our findings indicate that the current net-zero pledges bring the world close to a well-below 2°C pathway, but a gap remains. Increasing ambition proves crucial to dealing with the climate challenge: expanding the global coverage of net-zero pledges and speeding up action increases consistency with the Paris goals (1.5 to 2.0°C range in model mean, 50th percentile). However, reaching the 1.5°C goal without overshoot seems increasingly unlikely, and dedicated policies are needed to reduce the reliance on fossil fuels and increase renewable energy capacity.