bluuebunny/crossref_metadata_2025_split huggingface dataset:
Boost Systems for Helicopter Gas Turbines
Authors: Morley A W 
Published: October 2023

The CHAIRMAN, in introducing the Author, said that Dr Morley had been for 16 years on the scientific staff of the Engine Department of the Royal Aircraft Establishment and, at the end of the war, was Deputy Head of the Gas Dynamics Division which subsequently became the Supersonics Division Three years after that he was senior lecturer of aircraft propulsion at Cranfield In his present position as Forward Projects Engineer for the Napier Company he was engaged on technical investigations into developments in aeronauticsThe recent years have seen a tremendous increase in the importance of the helicopter both as a defence aircraft, for anti mine, anti submarine and assault purposes and as a civil transport between busy centres, and it has been overwhelmingly successful in a multitude of special duties from rescue work to crop spraying, some impossible with fixed wing aircraft The wider application of the helicopter in these many roles has directed increased attention towards the enhanced engine performance possible with the gas turbine, and to the more difficult problems of coupling the greater potential output of this form of engine with the inherent safety features of the aircraft
Some Design Aspects of Tandem Rotor Helicopters
Authors: Sibley J D , Jones C H 
Published: October 2023

The Chairman, in opening the meeting, said that the first part of the Paper would be presented by Mr J D Sibley, who for the past 10 years had been Chief Aerodynamicist at the Helicopter Division, Bristol Aircraft Ltd, Weston-Super-Mare Mr Sibley would discuss the aerodynamic aspects The second part, relating to the dynamical aspects, would be presented by Mr C H Jones, who had been Dynamics Engineer at the Helicopter Division, Bristol Aircraft Ltd, since 1955 Afterwards there would be a short filmThe paper discusses a number of aerodynamic aspects which have appeared during the development of the Bristol Helicopters I have deliberately avoided excessive comparisons of the advantages and disadvantages of tandem helicopters versus the single main rotor helicopters, as this subject has been covered by numerous authorsThe subject matter covers information on performance, control and stability, which has been obtained in the course of development work on Bristol Tandem Helicopters Some of this information is directly applicable to other types of helicopter
Assessing Multi‐Dimensional Impacts of Achieving Sustainability Goals by Projecting the Sustainable Agriculture Matrix Into the Future
Authors: Kyle Page , Ollenburger Mary , Zhang Xin , Niazi Hassan , Durga Siddarth , Ou Yang 
Published: October 2023

AbstractThe concept of sustainability inherently spans multiple spatial scales, sectors, variables, and time horizons. This study links a recently developed method of assessing present‐day agricultural sustainability across environmental, economic, and social dimensions with a process‐based integrated assessment model, in order to allow forward‐looking analysis of sustainability by region and scenario. The sustainable agriculture matrix estimates present‐day agricultural sustainability at the national level using 18 indicator variables, of which this study estimates nine to the year 2100, using an enhanced version of the Global Change Analysis Model. Scenarios include a reference scenario, and scenarios that apply the following measures, both individually and in combination, that are thought to improve sustainability: yield intensification, transition toward more plant‐based (“flexitarian”) diets, and economy‐wide greenhouse gas emissions mitigation. The scenarios illustrate considerable complexity and tradeoffs inherent to efforts to improve agricultural sustainability in all regions globally. For example, yield intensification typically increases nitrogen pollution, flexitarian diets can reduce agricultural output, and greenhouse gas mitigation efforts may either increase deforestation or crowd out crop and livestock production due to consequent bioenergy demands. However, there is considerable inter‐regional heterogeneity in the responses, and the importance of such secondary responses also differs by region. The analysis and post‐processing methods developed in this study allow quantification and visualization of the absolute and relative magnitude of the tradeoffs between agricultural sustainability indicator variables across regions, time periods, and scenarios.
Efficient Optimization of a Regional Water Elevation Model With an Automatically Generated Adjoint
Authors: Kärnä Tuomas , Wallwork Joseph G. , Kramer Stephan C. 
Published: October 2023

AbstractCalibration of unknown model parameters is a common task in many ocean model applications. We present an adjoint‐based optimization of an unstructured mesh shallow water model for the Baltic Sea. Spatially varying bottom friction parameter is tuned to minimize the misfit with respect to tide gauge sea surface height (SSH) observations. A key benefit of adjoint‐based optimization is that computational cost does not depend on the number of unknown variables. Adjoint models are, however, typically very laborious to implement. In this work, we leverage a domain specific language framework in which the discrete adjoint model can be obtained automatically. The adjoint model is both exactly compatible with the discrete forward model and computationally efficient. A gradient‐based quasi‐Newton method is used to minimize the misfit. Optimizing spatially‐variable parameters is typically an under‐determined problem and can lead to over‐fitting. We employ Hessian‐based regularization to penalize the spatial curvature of the friction field to overcome this problem. The SSH dynamics in the Baltic Sea are simulated for a 3‐month period. Optimization of the bottom friction parameter results in significant improvement of the model performance. The results are especially encouraging in the complex Danish Straits region, highlighting the benefit of unstructured meshes. Domain specific language frameworks enable automated model analysis and provide easy access to adjoint modeling. Our application shows that this capability can be enabled with few efforts, and the optimization procedure is robust and computationally efficient.
Macroecology Differentiation Between Bacteria and Fungi in Topsoil Across the United States
Authors: He Liyuan , Viovy Nicolas , Xu Xiaofeng 
Published: October 2023

AbstractBacteria and fungi possess distinct physiological traits. Their macroecology is vital for ecosystem functioning such as carbon cycling. However, bacterial and fungal biogeography and underlying mechanisms remain elusive. In this study, we investigated bacterial versus fungal macroecology by integrating a microbial‐explicit model—CLM‐Microbe—with measured fungal (FBC) and bacterial biomass carbon (BBC) from 34 NEON sites. The distribution of FBC, BBC, and FBC: BBC (F:B) ratio was well simulated across sites, with variations in 99% (P < 0.001), 97% (P < 0.001), and 99% (P < 0.001) being explained by the CLM‐Microbe model, respectively. We found stronger biogeographic patterns of FBC relative to BBC across the United States. Fungal and bacterial turnover rates showed similar trends along latitude. However, latitudinal trends of their component fluxes (carbon assimilation, respiration, and necromass production) were distinct between bacteria and fungi, with those latitudinal trends following inverse unimodal patterns for fungi and showing exponential declining responses for bacteria. Carbon assimilation was dominated by vegetation productivity, and respiration was dominated by mean annual temperature for bacteria and fungi. The dominant factor for their necromass production differs, with edaphic factors controlling fungal and mean annual temperature controlling bacterial processes. The understanding of fungal and bacterial macroecology is an important step toward linking microbial metabolism and soil biogeochemical processes. Distinct fungal and bacterial macroecology contributes to the microbial ecology, particularly on microbial community structure and its association with ecosystem carbon cycling across space.
Revisiting a Constraint on Equilibrium Climate Sensitivity From a Last Millennium Perspective
Authors: Cropper S. , Thackeray C. W. , Emile‐Geay J. 
Published: October 2023

AbstractDespite decades of effort to constrain equilibrium climate sensitivity (ECS), current best estimates still exhibit a large spread. Past studies have sought to reduce ECS uncertainty through a variety of methods including emergent constraints. One example uses global temperature variability over the past century to constrain ECS. While this method shows promise, it has been criticized for its susceptibility to the influence of anthropogenic forcing and the limited length of the instrumental record used to compute temperature variability. Here, we investigate the emergent relationship between ECS and two metrics of global temperature variability using model simulations and paleoclimate reconstructions over the last millennium (850–1999). We find empirical evidence in support of these emergent relationships. Observational constraints suggest a central ECS estimate of 2.5–2.7 K, consistent with the Intergovernmental Panel on Climate Change's consensus estimate of 3K. Moreover, they suggest ECS “likely” ranges of 1.7–3.3 K and 1.9–3.5 K.
Ionospheric and Atmospheric Response to Extremely Severe Cyclonic Storm Nida of 29 July–02 August 2016
Authors: Kumar Sanjay , Chen Wu , Louis Osei‐Poku 
Published: October 2023

AbstractTropical cyclones are one of the biggest threats to life and property. During cyclone period storm surge, flooding, extreme winds, tornadoes and lighting cause significant impacts on life and property and hence affects life of human being to a great extent. Nida was the third tropical cyclone requiring the issuance of tropical cyclone warning signals by the Hong Kong Observatory in 2016 and maximum hourly mean winds of 158 km/hr was recorded in Hong Kong. It affected many cities of China and about 500,000 people, more than 300 houses collapsed and made economic loss of about 500 million RMB. Investigation of lightning discharges around the cyclone track line revealed that the strong lightning activity is noticed during the cyclone period with a super lightning maxima on 30 July and 01 August. The effect of this typhoon on the ionosphere is studied using the TEC data from GPS measurements taken around the cyclone track and satellite based COSMIC measurements. Strong convective activity which is driver for the thunderstorm and gravity waves activity noticed from the negative cloud top temperature as low as −50°C observed from AIRS satellite during the cyclone period. Significant enhancement is atmospheric ozone is observed during the cyclone period which could be attributed to thunderstorm activity present during the cyclone period. The analysis found decrease in GPS‐TEC data at stations around Hong Kong region during the landfall of the cyclone. The magnitude of perturbation in TEC is found larger at stations lying toward right/eastward of the cyclone track as compared to those in the left/westward from the cyclone track. In addition, periodic signatures in ionospheric TEC data were also detected. Continuous wavelet transform to DTEC data has been made to estimate period and found the periodic structure in ionospheric TEC belongs to AGWs with period 9–20 min and frequency 1–2 mHz. Strong scintillation activity as high as S4‐index 1.35 from GPS measurements has been noticed at Sanya station during cyclone period on 02 August which is further confirmed by satellite based measurements from COSMIC. Both measurements show maximum scintillation activity during 1400–1600 UT. The strong scintillation activity as compared to normal days observed during the cyclone period is attributed to lightning induced electric filed as well as generation of AGWs due to deep convection which could act as seed perturbation for generation of ionospheric irregularities by Rayleigh‐Taylor instability mechanism.
Plagioclase Lherzolite Melting: Experimental Constraints on a Primary, High‐Alumina MORB From the Southwest Indian Ridge
Authors: Beaudry Patrick , Krein Stephanie B. , Grove Timothy L. 
Published: October 2023

AbstractWe experimentally investigated the phase relations of a primary basaltic glass erupted on the 10–15°E ultraslow spreading (∼0.4 cm/yr) oblique amagmatic segment of the Southwest Indian Ridge (SWIR). Piston‐cylinder experiments were conducted at 9–13 kbar and 1270–1310°C, in accordance with the predicted pressure and temperature (9.5 ± 0.8 kbar and 1290 ± 12°C) of saturation with a mantle lherzolite assemblage using the recently developed multiphase reverse fractional crystallization model ReversePetrogen (RevPet, Krein et al., 2021, https://doi.org/10.1029/2020JB021292). The experiments were multiply saturated with a plagioclase lherzolite assemblage (olivine + augite + orthopyroxene + plagioclase) at 10 kbar and 1290°C, within the uncertainty of the RevPet prediction. We use the forward model Petrogen (Krein et al., 2020, https://doi.org/10.1029/2020JB019612) to find the best fitting mantle composition and melting conditions that could produce glass KN162‐9 48‐21. This model independently finds a melting pressure and temperature of 9.5 kbar and 1285°C, which agree remarkably well with the RevPet predictions and our experiments. This sample is also significantly more depleted in incompatible trace elements than other glasses from the same ridge segment, suggesting its mantle source experienced prior episodes of depletion. This is consistent with previous work suggesting that ultraslow spreading at the SWIR preserves heterogeneities on a local scale. The variability of erupted compositions largely reflects aggregation and mixing of heterogeneous near‐fractional melts produced in the spinel and plagioclase stability fields along similar melting paths and their fractional crystallization products. More generally, plagioclase‐field mantle melting does occur at mid‐ocean ridges and is preserved in some melting environments.
Impact of Updating Vegetation Information on Land Surface Model Performance
Authors: Ruiz‐Vásquez Melissa , O Sungmin , Arduini Gabriele , Boussetta Souhail , Brenning Alexander , Bastos Ana , Koirala Sujan , Balsamo Gianpaolo , Reichstein Markus , Orth René 
Published: October 2023

AbstractVegetation plays a fundamental role in modulating the exchange of water, energy, and carbon fluxes between the land and the atmosphere. These exchanges are modeled by Land Surface Models (LSMs), which are an essential part of numerical weather prediction and data assimilation. However, most current LSMs implemented specifically in weather forecasting systems use climatological vegetation indices, and land use/land cover data sets in these models are often outdated. In this study, we update land surface data in the European Centre for Medium‐range Weather Forecast (ECMWF) land surface modeling system (ECLand) using Earth observation‐based time varying leaf area index and land use/land cover data, and evaluate the impact of vegetation dynamics on model performance. The performance of the simulated latent heat flux and soil moisture is then evaluated against global gridded observation‐based data sets. Updating the vegetation information does not always yield better model performances because the model's parameters are adapted to the previously employed land surface information. Therefore we recalibrate key soil and vegetation‐related parameters at individual grid cells to adjust the model parameterizations to the new land surface information. This substantially improves model performance and demonstrates the benefits of updated vegetation information. Interestingly, we find that a regional parameter calibration outperforms a globally uniform adjustment of parameters, indicating that parameters should sufficiently reflect spatial variability in the land surface. Our results highlight that newly available Earth‐observation products of vegetation dynamics and land cover changes can improve land surface model performances, which in turn can contribute to more accurate weather forecasts.
Glycobiology in osteoclast differentiation and function
Authors: Yang Shufa , He Ziyi , Wu Tuo , Wang Shunlei , Dai Hui 
Published: October 2023

AbstractGlycans, either alone or in complex with glycan-binding proteins, are essential structures that can regulate cell biology by mediating protein stability or receptor dimerization under physiological and pathological conditions. Certain glycans are ligands for lectins, which are carbohydrate-specific receptors. Bone is a complex tissue that provides mechanical support for muscles and joints, and the regulation of bone mass in mammals is governed by complex interplay between bone-forming cells, called osteoblasts, and bone-resorbing cells, called osteoclasts. Bone erosion occurs when bone resorption notably exceeds bone formation. Osteoclasts may be activated during cancer, leading to a range of symptoms, including bone pain, fracture, and spinal cord compression. Our understanding of the role of protein glycosylation in cells and tissues involved in osteoclastogenesis suggests that glycosylation-based treatments can be used in the management of diseases. The aims of this review are to clarify the process of bone resorption and investigate the signaling pathways mediated by glycosylation and their roles in osteoclast biology. Moreover, we aim to outline how the lessons learned about these approaches are paving the way for future glycobiology-focused therapeutics.
Genetic interactions between polycystin-1 and Wwtr1 in osteoblasts define a novel mechanosensing mechanism regulating bone formation in mice
Authors: Xiao Zhousheng , Cao Li , Smith Micholas Dean , Li Hanxuan , Li Wei , Smith Jeremy C. , Quarles Leigh Darryl 
Published: October 2023

AbstractMolecular mechanisms transducing physical forces in the bone microenvironment to regulate bone mass are poorly understood. Here, we used mouse genetics, mechanical loading, and pharmacological approaches to test the possibility that polycystin-1 and Wwtr1 have interdependent mechanosensing functions in osteoblasts. We created and compared the skeletal phenotypes of control Pkd1flox/+;Wwtr1flox/+, Pkd1Oc-cKO, Wwtr1Oc-cKO, and Pkd1/Wwtr1Oc-cKO mice to investigate genetic interactions. Consistent with an interaction between polycystins and Wwtr1 in bone in vivo, Pkd1/Wwtr1Oc-cKO mice exhibited greater reductions of BMD and periosteal MAR than either Wwtr1Oc-cKO or Pkd1Oc-cKO mice. Micro-CT 3D image analysis indicated that the reduction in bone mass was due to greater loss in both trabecular bone volume and cortical bone thickness in Pkd1/Wwtr1Oc-cKO mice compared to either Pkd1Oc-cKO or Wwtr1Oc-cKO mice. Pkd1/Wwtr1Oc-cKO mice also displayed additive reductions in mechanosensing and osteogenic gene expression profiles in bone compared to Pkd1Oc-cKO or Wwtr1Oc-cKO mice. Moreover, we found that Pkd1/Wwtr1Oc-cKO mice exhibited impaired responses to tibia mechanical loading in vivo and attenuation of load-induced mechanosensing gene expression compared to control mice. Finally, control mice treated with a small molecule mechanomimetic, MS2 that activates the polycystin complex resulted in marked increases in femoral BMD and periosteal MAR compared to vehicle control. In contrast, Pkd1/Wwtr1Oc-cKO mice were resistant to the anabolic effects of MS2. These findings suggest that PC1 and Wwtr1 form an anabolic mechanotransduction signaling complex that mediates mechanical loading responses and serves as a potential novel therapeutic target for treating osteoporosis.
Trim21 depletion alleviates bone loss in osteoporosis via activation of YAP1/β-catenin signaling
Authors: Liu Ri-Xu , Gu Rong-He , Li Zhi-Peng , Hao Zhi-Quan , Hu Qin-Xiao , Li Zhen-Yan , Wang Xiao-Gang , Tang Wang , Wang Xiao-He , Zeng Yu-Kai , Li Zhen-Wei , Dong Qiu , Zhu Xiao-Feng , Chen Di , Zhao Ke-Wei , Zhang Rong-Hua , Zha Zhen-Gang , Zhang Huan-Tian 
Published: October 2023

AbstractDespite the diverse roles of tripartite motif (Trim)-containing proteins in the regulation of autophagy, the innate immune response, and cell differentiation, their roles in skeletal diseases are largely unknown. We recently demonstrated that Trim21 plays a crucial role in regulating osteoblast (OB) differentiation in osteosarcoma. However, how Trim21 contributes to skeletal degenerative disorders, including osteoporosis, remains unknown. First, human and mouse bone specimens were evaluated, and the results showed that Trim21 expression was significantly elevated in bone tissues obtained from osteoporosis patients. Next, we found that global knockout of the Trim21 gene (KO, Trim21−/−) resulted in higher bone mass compared to that of the control littermates. We further demonstrated that loss of Trim21 promoted bone formation by enhancing the osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) and elevating the activity of OBs; moreover, Trim21 depletion suppressed osteoclast (OC) formation of RAW264.7 cells. In addition, the differentiation of OCs from bone marrow-derived macrophages (BMMs) isolated from Trim21−/− and Ctsk-cre; Trim21f/f mice was largely compromised compared to that of the littermate control mice. Mechanistically, YAP1/β-catenin signaling was identified and demonstrated to be required for the Trim21-mediated osteogenic differentiation of BMSCs. More importantly, the loss of Trim21 prevented ovariectomy (OVX)- and lipopolysaccharide (LPS)-induced bone loss in vivo by orchestrating the coupling of OBs and OCs through YAP1 signaling. Our current study demonstrated that Trim21 is crucial for regulating OB-mediated bone formation and OC-mediated bone resorption, thereby providing a basis for exploring Trim21 as a novel dual-targeting approach for treating osteoporosis and pathological bone loss.
Urban land patterns can moderate population exposures to climate extremes over the 21st century
Authors: Gao Jing , Bukovsky Melissa S. 
Published: October 2023

AbstractClimate change and global urbanization have often been anticipated to increase future population exposure (frequency and intensity) to extreme weather over the coming decades. Here we examine how changes in urban land extent, population, and climate will respectively and collectively affect spatial patterns of future population exposures to climate extremes (including hot days, cold days, heavy rainfalls, and severe thunderstorm environments) across the continental U.S. at the end of the 21st century. Different from common impressions, we find that urban land patterns can sometimes reduce rather than increase population exposures to climate extremes, even heat extremes, and that spatial patterns instead of total quantities of urban land are more influential to population exposures. Our findings lead to preliminary suggestions for embedding long-term climate resilience in urban and regional land-use system designs, and strongly motivate searches for optimal spatial urban land patterns that can robustly moderate population exposures to climate extremes throughout the 21st century.