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Masambuka-Kanchewa, Fallys, Mary Rodriguez, Emily Buck, Jera Niewoehner-Green, and Alexa Lamm. "Impact of Agricultural Communication Interventions on Improving Agricultural Productivity in Malawi." Journal of International Agricultural and Extension Education 27, no. 3 (August 19, 2020): 116–31. http://dx.doi.org/10.5191/jiaee.2020.273116.
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Agricultural communication (AGCOM) has been known to aid in disseminating research-based agricultural information among Malawian farmers. In 1958 the Malawi Government, via the Ministry of Agriculture, established the Agricultural Communications Branch (ACB) in an attempt to increase access to and adoption of scientifically-proven technologies among farmers. Moreover, in 2000 the Malawi Government started implementing an agricultural extension policy that promoted pluralistic demand-driven extension, which led to the increased availability of non-governmental organizations providing AGCOM services to farmers. However, after several decades of using different communication tools to promote new technologies, low productivity in most small holder farms remains a challenge, with limited adoption of improved technology as one of the contributing factors. In this exploratory, convergent, mixed methods study, 30 Malawian farmers and six AGCOM officers who were selected using convenient and snow ball sampling respectively participated in key informant interviews. In addition, 64 AGCOM officers who were selected using simple random sampling were involved in a survey. The findings of the study revealed that information delivered to farmers does not address farmer needs in most cases. Specifically, existing policies, source and availability of funding, and the agricultural calendar influenced choice of information that was disseminated. For example, the existing policy does not allow AGCOM officers to disseminate local and innovative farmer practices unless they are tested and approved by scientists. Such policies, perpetuates a mindset among farmers that innovations originate from outside their communities, thereby making it hard for them to share their local, indigenous ideas with their colleagues. Moreover, it has contributed to the inability of AGCOM to be used as an innovation creation tool, hence AGCOMs’ limited impact. Keywords: adoption, improved technologies, agricultural communication, increased productivity, information dissemination
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Verdier-Bonchut, Virginie. "Regulation of the Audiovisual and Telecommunications Sector in Italy: From Community Challenge to National Issue." International Review of Administrative Sciences 69, no. 2 (June 2003): 271–83. http://dx.doi.org/10.1177/0020852303069002010.
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Regulation of the telecommunications and audiovisual sector is a legal, economic and even political necessity. While its exercise by an allegedly independent (administrative) authority is recognized by the Community institutions and all member states, its role and powers differ from country to country. From this point of view, Italy is an atypical case. The authority for guarantees in communication, Agcom, which was a result of Community demands, is the only structure (within the member states) that incorporates the principle of convergence. However, while this is, undeniably, a legal process and, above all, complies with the wishes of the Community, Agcom must face up to many criticisms and these once again give rise to a discussion of the role of the independent (administrative) authorities within the administration.
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Marrazzo, Francesco. "Italian communication professionals: a comparison among public and private sector ones in search of sediments of innovation." SOCIOLOGIA DELLA COMUNICAZIONE, no. 61 (July 2021): 149–58. http://dx.doi.org/10.3280/sc2021-061010.
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The Covid-19 emergency has made evident the need for a new approach to public communication and, consequently, the update of the public sector commu-nicators skills. Starting from the analysis of the differences between professional condition, education, digital competence level and, especially, working activities carried out by public sector and private sector communicators who have partici-pated in an Italian media regulatory authority (AGCOM) survey, the goal of these contribution is to identify those elements of innovation in private sector communi-cators job that could be useful in shaping a new professional figure suitable for the evolution of the public communication role in a increasingly disintermediated in-formation environment.
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da Empoli, Stefano. "The Regulatory Management in the Energy and Electronic Communications Sectors: Towards Institutional Convergence?" Journal of Public Finance and Public Choice 23, no. 1 (April 1, 2005): 87–97. http://dx.doi.org/10.1332/251569205x15664514109184.
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Abstract Regulatory authorities in the energy and electronic communications sectors have followed a parallel pattern due to the liberalization process that has interested the two sectors during the last decade in Europe. The reason can be partly traced back to a same legislative origin (EU directives promoted by the European Commission). In some European countries, a single authority is envisioned as a conclusion to such a common institutional path. This article inquires if institutional convergence may be justified by similar regulatory needs. Based on several critical factors, it is argued, however, that a different institutional design for the two regulatory authorities would be a more efficient solution.These findings are then applied to the Italian case, where the Energy Authority (AEEG) and the Communications Authority (AGCOM) were set up during the late 90s. In this case, no particular convergence can be found. However, differences reflect a heavily inefficient institutional design.
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Nguyen, Ngoc-Thang, and Thi-Lan-Huong Vo. "Fabrication of Silver Nanoparticles Using Cordyline fruticosa L. Leave Extract Endowing Silk Fibroin Modified Viscose Fabric with Durable Antibacterial Property." Polymers 14, no. 12 (June 14, 2022): 2409. http://dx.doi.org/10.3390/polym14122409.
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The current work presented a green synthetic route for the fabrication of silver nanoparticles obtained from aqueous solutions of silver nitrate using Cordyline fruticosa L. leaf extract (Col) as a reducing and capping agent for the first time. The bio-synthesized silver nanoparticles (AgCol) were investigated using UV–visible spectroscopy (UV–vis), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and thermal gravimetric analysis (TGA). The obtained data demonstrated that AgCol in spherical shape with an average size of 28.5 nm were highly crystalline and well capped by phytocompounds from the Col extract. Moreover, the bio-synthesized AgCol also exhibited the effective antibacterial activities against six pathogenic bacteria, including Escherichia coli (E. coli), Pseudomonas aeruginosa (P. aeruginosa), Salmonella enterica (S. enterica), Staphylococcus aureus (S. aureus), Bacillus cereus (B. cereus) and Enterococcus faecalis (E. faecalis). The AgCol were applied as an antibacterial finishing agent for viscose fabric using a pad-dry curing technique. The AgCol-treated viscose fabrics exhibited a good synergistic antimicrobial activity against E. coli and S. aureus bacteria. Furthermore, the silk fibroin regenerated from Bombyx mori cocoon waste was utilized as an ecofriendly binder for the immobilization of AgCol on the viscose fabric. Thus, the antimicrobial efficacy of the AgCol and fibroin modified viscose fabric still reached 99.99% against the tested bacteria, even after 30 washing cycles. The colorimetric property, morphology, elemental composition, and distribution of AgCol on the treated fabrics were investigated using several analysis tools, including colorimetry, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), atomic absorption spectroscopy (AAS), Kjeldahl, and FTIR. Because of the excellent antimicrobial efficiency and laundering durability, as well as the green synthesis method, the AgCol and fibroin modified viscose fabric could be utilized as an antibacterial material in sportswear and medical textile applications.
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Olsen, Doug, Changyong Dou, Xiaodong Zhang, Lianbo Hu, Hojin Kim, and Edward Hildum. "Radiometric Calibration for AgCam." Remote Sensing 2, no. 2 (February 1, 2010): 464–77. http://dx.doi.org/10.3390/rs2020464.
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Dänzer, Dieter. "Zoff bei Agco." agrarzeitung 76, no. 13 (2021): 9. http://dx.doi.org/10.51202/1869-9707-2021-13-009.
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Frankfurt a.M. Im Vorfeld der Hauptversammlung des Landtechnik-Anbieters Agco am 22. April im US-amerikanischen Duluth reicht ein Großaktionär Erklärungen bei der US-Börsenaufsicht ein. Darin fordert der Investor eine Ämtertrennung an der Spitze und wirft dem Konzern strategische Fehler vor.
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Dias, Cássia Gabriele, Michelle Simões Reboita, Lívia Márcia M. Dutra, and Rosmeri Porfírio Da Rocha. "Destreza de dois modelos climáticos globais em prever a circulação geral da atmosfera (Skill of two global climate models in forecasting the general circulation of the atmosphere)." Revista Brasileira de Geografia Física 10, no. 4 (July 13, 2017): 1090. http://dx.doi.org/10.26848/rbgf.v10.4.p1090-1099.
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O presente estudo avaliou a destreza de dois modelos climáticos globais (CFSv2 e AGCM-CPTEC) em prever a circulação atmosférica sazonal sobre a América do Sul (AS). As previsões entre os anos de 2013 e início de 2014 foram comparadas com os dados da reanálise ERA-Interim. No nível de 250 hPa, o CFSv2 previu o jato subtropical mais fraco do que o observado na reanálise, enquanto o AGCM-CPTEC o previu mais intenso durante o inverno e primavera. Nos meses de Setembro, Outubro e Novembro (SON) de 2013, a Alta da Bolívia (AB) esteve bem configurada no AGCM-CPTEC, concordando com a reanálise. No entanto, com o modelo CFSv2 a AB não se configurou. Já entre os meses de Janeiro, Fevereiro e Março (JFM) de 2014, os modelos deslocaram a AB para sudoeste de sua posição climatológica. No nível de 850 hPa, os jatos de baixos níveis a leste dos Andes foram subestimados nos meses de Março, Abril e Maio (MAM) com o AGCM-CPTEC e em SON/JFM por ambos os modelos. Em MAM, o CFSv2 previu os ventos alísios de sudeste mais similar à reanálise do que o AGCM-CPTEC. O Anticiclone Subtropical do Atlântico Sul (ASAS) foi previsto em ambos os modelos, entretanto, o AGCM-CPTEC previu a intensidade e a posição desse sistema com mais acurácia. Embora os modelos CFSv2 e AGCM-CPTEC apresentem vieses na intensidade do vento e, às vezes, na direção, pode-se afirmar que esses representaram as principais características da circulação atmosférica na AS. A B S T R A C TThe present study evaluated the ability of two global climate models (CFSv2 and AGCM-CPTEC) in predicting the seasonal atmospheric circulation over South America (SA). Predictions between the years 2013 and early 2014 were compared with ERA-Interim reanalysis. At 250 hPa level, CFSv2 predicted the subtropical jet weaker than observed in the reanalysis, while AGCM-CPTEC predicted it more intense during winter and spring. In the months of September, October and November (SON) of 2013, the Bolivian High (BH) was well configured in the AGCM-CPTEC, and this was in agreement with the reanalysis. However, with the CFSv2 the BH was not predicted. Between the months of January, February and March (JFM) of 2014, the models displaced the BH to the southwest of its climatologic position. At the 850 hPa level, the low level jet eastern of the Andes was underestimated in the months of March, April and May (MAM) by AGCM-CPTEC and in SON/JFM by both models. In MAM, CFSv2 predicted better the southeast trade winds than AGCM-CPTEC. The South Atlantic Subtropical Anticyclone (SASA) was predicted by both models, however, the AGCM-CPTEC predicted the intensity and position of this system more accurately. Although the models show biases in the wind intensity and, sometimes, in the direction, it can be affirmed that in general the CFSv2 and AGCM-CPTEC models represented the main characteristics of the atmospheric circulation in the AS.Keywords: AGCM-CPTEC. CFSv2. General circulation of the atmosphere. Seasonal forecast. South America.
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Lee, You-Kyung. "The Relationship between Green Country Image, Green Trust, and Purchase Intention of Korean Products: Focusing on Vietnamese Gen Z Consumers." Sustainability 12, no. 12 (June 23, 2020): 5098. http://dx.doi.org/10.3390/su12125098.
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This study aims to extend the stream of country image research through an empirical test primarily focusing on the relationship between the green country image of Korea, as well as the green trust and purchase intention of Korean products considering Vietnamese Generation Z (hereafter Gen Z) consumers. Data were collected in November 2019 through an online survey, and 440 data samples were identified and used for conducting the data analysis. The sample was divided into Vietnamese consumers residing in Korea and Vietnam. Firstly, an examination of the variance revealed that Vietnamese Gen Z consumers residing in Vietnam (VZV) displayed less positive perceptions of the constructs measured compared to Vietnamese Gen Z consumers residing in Korea (VZK), including cognitive green country image (CGCoI), affective green country image (AGCoI) of Korea, and also green trust (GT) and purchase intention (PI) of Korean products. Second, results from the structural equation model of VZV showed that CGCoI had a significant impact on the PI, while AGCoI had a significant impact on GT. Conversely, for VZK, it was found that CGCoI had a significant impact on PI, and that AGCoI had a significant impact on both GT and PI. Thirdly, the results of comparing the path coefficient between VZV and VZK showed that the impact of CGCoI and AGCoI on PI were stronger for VZK, whereas the impact of AGCoI on GT was stronger for VZV. Based on these findings, the study discusses practical and theoretical implications for future green marketing practices in Vietnam.
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Jamil, Muhammad, Salman Shahzad, Shahbaz Hussain, Hamza Ali Bukhari, and Anwar Ul Huda. "Comparison of Manual Mode With Automatic Gas Control Mode for Sevoflurane Consumption in Maquet Flow-I Anesthesia Machine." Pakistan Journal of Medical and Health Sciences 16, no. 10 (October 30, 2022): 15–17. http://dx.doi.org/10.53350/pjmhs22161015.
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Background: Inhalational anesthetic agents used for general anesthesia can have adverse effects on operation theater staff and environment. The innovative automated gas controller reduces inhalational anesthesia agent consumption. Aim: To compare sevoflurane consumption in manual mode versus automatic gas control (AGCTM) mode on Maquet Flow-i anesthesia machine in adult laparoscopic surgeries. Methods: This study was a randomized control trail conducted at Department of anesthesia, Security Forces Hospital Riyadh, Saudi Arabia and Pakistan Kidney and Liver Institute and Research Center, Lahore, Pakistan from December 2019 till December 2020. Sixty patients were randomly divided into two Groups A (Automatic Gas Control, AGCTM) and Group B (Manual Mode). Sevoflurane consumption and sevoflurane consumption rate was calculated in both groups. Data was analyzed using SPSS V.20. Results: Two groups were comparable in term of age, gender, and comorbidities. The mean sevoflurane consumption rate in group A was 23.92+4.6 as compared to 40.23+4.4 in group B (P=0.001). Similarly sevoflurane consumption rate is also statistically significant. (0.28 + 0.04 ml/min vs 0.47 + 0.02 ml/min, p=0.001) Conclusion: Sevoflurane consumption and sevoflurane consumption rate is lower in AGCTM mode as compared to manual mode of Maquet Flow-I anesthesia machine. Keywords: Sevoflurane, Maquet Flow-i, Automatic Gas Controller (AGCTM), Laparoscopic Surgeries
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Boßmann, Florian, and Jianwei Ma. "Asymmetric chirplet transform — Part 2: Phase, frequency, and chirp rate." GEOPHYSICS 81, no. 6 (November 2016): V425—V439. http://dx.doi.org/10.1190/geo2015-0696.1.
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An asymmetric chirplet transform, also called the asymmetric Gaussian chirplet model (AGCM), was recently introduced for fast and accurate extraction of important information from seismic signals. Unlike Fourier or wavelet transforms with fixed base functions, the AGCM is an adaptive sparse representation based on the physical parameters of the given data. The atoms of AGCM, so-called chirplets, display asymmetric oscillation-attenuation properties. The AGCM decomposes seismic signals into nonstationary compressed plane waves. The waves or atoms consist of two parts with seven physical parameters: the envelope and frequency parts. We have determined how to reconstruct the envelope part (e.g., envelope amplitude and arrival time) of the seismic data. We concentrate on the frequency part that involves three parameters: phase, frequency, and chirp rate. A Newton method with a step-size choice is established to deal with the highly oscillating frequency part of AGCM. The model parameters or coefficients in the transform domain may not only provide explicit physical interpretation (e.g., local phase of signal), but they can also be potentially used for feature extraction and other applications. Numerical results indicate excellent approximation results with good runtime performance. Physically reasonable parameter interpretation is demonstrated.
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Gurrola, Manuel, and Ruxandra Mihaela Botez. "Improved Local Scale Generic Cycle Model for Aerothermodynamic Simulations of Gas Turbine Engines for Propulsion." Designs 6, no. 5 (October 3, 2022): 91. http://dx.doi.org/10.3390/designs6050091.
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A local scale Aerothermodynamic Generic Cycle Model (AGCM) is proposed. The AGCM accounts for several improvements not considered in similar models, such as compressor bleed extraction for aircraft Environmental Control System (ECS), parasitic shaft power extraction, and the enthalpy of the fuel entering the combustor. The AGCM is intended for steady-state Design Point (DP) and Off-Design (OD) performance analyses. The underlying physics is presented for the DP model. The turbomachinery component maps scaling and the system of nonlinear equations necessary to define the OD model are thoroughly discussed. The AGCM is compared with an equivalent model developed in the Numerical Propulsion System Simulation (NPSS). The comparisons were performed considering a DP envisioned to approximate a General Electric CF34-8C5B1 engine. The average errors found in these comparisons for the Specific Fuel Consumption (SFC) and net thrust were −0.111% and 0.193%, respectively. Finally, the predictions of the absolute levels of performance intended for the -8C5B1 engine are compared with empirical correlations derived from a comprehensive turbofan engine database. It was found that the predictions of the AGCM are in agreement with the empirical correlations; the errors found in SFC and net thrust at cruise flight condition were −0.43% and 2.06%, respectively.
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Fedosyuk, V. M., O. I. Kasyutich, and W. Schwarzacher. "Granular AgCo and AgCuCo nanowires." Journal of Magnetism and Magnetic Materials 198-199 (June 1999): 246–47. http://dx.doi.org/10.1016/s0304-8853(98)01099-3.
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Ismail, Alshimaa H., Germien G. Sedhom, and Zainab H. Ali. "Enhanced Active Queue Management‑Based Green Cloud Model for 5G system using K-Means." International Journal of Wireless and Ad Hoc Communication 6, no. 2 (2023): 65–72. http://dx.doi.org/10.54216/ijwac.060206.
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The most unique and important design considerations in 5G cloud computing are the delay, energy consumption, and throughput. Therefore, most recent studies focused on boosting delay and energy consumption, and throughput using edge computing. The active queue management-based green cloud model (AGCM) is one of the most recent green cloud models that decreases the delay and sustains a stable throughput. Also, Mobile edge computing (MEC) is an essential cloud computing model for mobile users to meet the continuous growth of data requests. Thus, we offer a handoff scenario between the AGCM and MEC to assess the possible benefits of such collaboration and enhance its effects on the fundamental cloud restrictions such as delay and throughput. Accordingly, the proposed algorithm is named Enhanced Active queue management-based green cloud model (EAGCM). The proposed EAGCM regards incorporation between Kmeans and AGCM. The simulation results indicate that the proposed EAGCM serves mobile users efficiently, enhances the throughput, and reduces latency compared to AGCM and the cloud for 5G systems.
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Yamagishi, Takateru, Ayako Abe-Ouchi, Fuyuki Saito, Tomonori Segawa, and Teruyuki Nishimura. "Re-evaluation of paleo-accumulation parameterization over Northern Hemisphere ice sheets during the ice age examined with a high-resolution AGCM and a 3-D ice-sheet model." Annals of Glaciology 42 (2005): 433–40. http://dx.doi.org/10.3189/172756405781813032.
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AbstractSimulations of the Northern Hemisphere ice sheet at the Last Glacial Maximum (LGM; 21 kyr BP) are performed using a high-resolution atmospheric general circulation model (AGCM) in order to re-evaluate the conventional surface temperature- or elevation-based parameterization. The influence of precipitation change on the steady-state topography of the Laurentide ice sheet at the LGM is estimated using an AGCM with a horizontal resolution of ∼1° and a three-dimensional thermomechanically coupled ice-sheet model. The ice volume estimated by the AGCM simulation is much larger than that indicated by the conventional parameterization. Through sensitivity analysis of the AGCM and ice-sheet model, it is found that the rate of precipitation change depends on the location of the ice sheet, and that the rate of precipitation change due to surface elevation change is higher than the rate unrelated to surface elevation change on the Laurentide ice sheet. The rate of precipitation is also shown to exhibit seasonality and regionality due to effects such as interior desertification and the concentration of storm tracks.
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Baalousha, Mohammed, Kamelia Afshinnia, and Laodong Guo. "Natural organic matter composition determines the molecular nature of silver nanomaterial-NOM corona." Environmental Science: Nano 5, no. 4 (2018): 868–81. http://dx.doi.org/10.1039/c8en00018b.
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Sun, Liqiang, David Ferran Moncunill, Huilan Li, Antonio Divino Moura, and Franciscode Assisde Souza Filho. "Climate Downscaling over Nordeste, Brazil, Using the NCEP RSM97." Journal of Climate 18, no. 4 (February 15, 2005): 551–67. http://dx.doi.org/10.1175/jcli-3266.1.
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Abstract The NCEP Regional Spectral Model (RSM), with horizontal resolution of 60 km, was used to downscale the ECHAM4.5 AGCM (T42) simulations forced with observed SSTs over northeast Brazil. An ensemble of 10 runs for the period January–June 1971–2000 was used in this study. The RSM can resolve the spatial patterns of observed seasonal precipitation and capture the interannual variability of observed seasonal precipitation as well. The AGCM bias in displacement of the Atlantic ITCZ is partially corrected in the RSM. The RSM probability distribution function of seasonal precipitation anomalies is in better agreement with observations than that of the driving AGCM. Good potential prediction skills are demonstrated by the RSM in predicting the interannual variability of regional seasonal precipitation. The RSM can also capture the interannual variability of observed precipitation at intraseasonal time scales, such as precipitation intensity distribution and dry spells. A drought index and a flooding index were adopted to indicate the severity of drought and flooding conditions, and their interannual variability was reproduced by the RSM. The overall RSM performance in the downscaled climate of the ECHAM4.5 AGCM is satisfactory over Nordeste. The primary deficiency is a systematic dry bias for precipitation simulation.
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Koster, Randal D., Yehui Chang, Hailan Wang, and Siegfried D. Schubert. "Impacts of Local Soil Moisture Anomalies on the Atmospheric Circulation and on Remote Surface Meteorological Fields during Boreal Summer: A Comprehensive Analysis over North America." Journal of Climate 29, no. 20 (September 27, 2016): 7345–64. http://dx.doi.org/10.1175/jcli-d-16-0192.1.
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Abstract A series of stationary wave model (SWM) experiments are performed in which the boreal summer atmosphere is forced, over a number of locations in the continental United States, with an idealized diabatic heating anomaly that mimics the atmospheric heating associated with a dry land surface. For localized heating within a large portion of the continental interior, regardless of the specific location of this heating, the spatial pattern of the forced atmospheric circulation anomaly (in terms of 250-hPa eddy streamfunction) is largely the same: a high anomaly forms over west-central North America and a low anomaly forms to the east. In supplemental atmospheric general circulation model (AGCM) experiments, similar results are found; imposing soil moisture dryness in the AGCM in different locations within the U.S. interior tends to produce the aforementioned pattern, along with an associated near-surface warming and precipitation deficit in the center of the continent. The SWM-based and AGCM-based patterns generally agree with composites generated using reanalysis and precipitation gauge data. The AGCM experiments also suggest that dry anomalies imposed in the lower Mississippi River valley have remote surface impacts of particularly large spatial extent, and a region along the eastern half of the U.S.–Canadian border is particularly sensitive to dry anomalies in a number of remote areas. Overall, the SWM and AGCM experiments support the idea of a positive feedback loop operating over the continent: dry surface conditions in many interior locations lead to changes in atmospheric circulation that act to enhance further the overall dryness of the continental interior.
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Nappi, Lucia, Marisa Thi, Amy Lum, David Huntsman, Bernie J. Eigl, Christopher Martin, Brock O’Neil, et al. "Developing a Highly Specific Biomarker for Germ Cell Malignancies: Plasma miR371 Expression Across the Germ Cell Malignancy Spectrum." Journal of Clinical Oncology 37, no. 33 (November 20, 2019): 3090–98. http://dx.doi.org/10.1200/jco.18.02057.
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PURPOSE Our objective was to evaluate operating characteristics, particularly specificity and positive predictive value (PPV), by mapping plasma miR371 expression to actual clinical events in patients with a history of germ cell tumor. PATIENTS AND METHODS One hundred eleven male patients with a history of or newly diagnosed germ cell tumors were evaluable. Biospecimens obtained before confirmed clinical events were analyzed for miR371 expression with blinding of providers and laboratory personnel to analytic results or clinical status, respectively. Cases (patients with clinically confirmed active germ cell malignancy [aGCM]) and controls (patients with no clinically confirmed aGCM) were assigned over the course of the management. Patients were assigned risk status (high, low, or moderate) based on the composite clinical picture at time points in management. RESULTS Considering all cases and controls and results of prospectively obtained biosamples analyzed for miR371 expression, 46 (35%) of 132 samples had clinically confirmed aGCM over the course of management; 44 (96%) of these 46 patients had plasma miR371 expression (true positives) with no false positives. Two (4%) of 46 patients had no miRNA expression despite pathologic confirmation of aGCM (false negatives). Plasma miR371 expression in confirmed aGCM had a specificity, sensitivity, positive predictive value, and negative predictive value of 100%, 96%, 100%, and 98%, respectively. Interpretation of sensitivity and negative predictive value is limited by modest follow-up. Specificity and sensitivity were 100% and 98%, 100% and 92%, and 100% and 97% in the low-, moderate-, and high-risk groups, respectively, with a median follow-up time of 15 months. CONCLUSION Plasma miR371 expression predicts aGCM with high specificity and positive predictive value. Although other operating characteristics of miR371 await longer follow-up for more complete definition, the findings of a highly specific liquid biopsy strongly support moving forward with large-scale, real-world clinical trials to further define full operating characteristics and to identify clinical utility and areas of patient benefit.
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Koster, R. D., S. D. Schubert, and M. J. Suarez. "Analyzing the Concurrence of Meteorological Droughts and Warm Periods, with Implications for the Determination of Evaporative Regime." Journal of Climate 22, no. 12 (June 15, 2009): 3331–41. http://dx.doi.org/10.1175/2008jcli2718.1.
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Abstract The hydroclimatic conditions under which a seasonal meteorological drought (below-normal seasonal rainfall) can induce an increase in seasonal air temperature are investigated, first with an atmospheric general circulation model (AGCM) and then with observations. Geographical differences in the dryness–warmth connection abound in the AGCM; in the United States, for example, identified evaporative controls tend to tie meteorological droughts to warmer temperatures in the South but not in the Northeast. The strong agreement between AGCM and observations-based geographical patterns of drought-induced warming supports the idea that the same evaporative controls are also present in nature. A powerful side benefit of the analysis of drought-induced warming is a Northern Hemisphere map, derived solely from observations, showing where total boreal summer evaporation is controlled by soil moisture, energy availability, or both.
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Nasluzov, Vladimir A., Elena A. Ivanova-Shor, Aleksey M. Shor, Svetlana S. Laletina, and Konstantin M. Neyman. "Adsorption and Oxidation of CO on Ceria Nanoparticles Exposing Single-Atom Pd and Ag: A DFT Modelling." Materials 14, no. 22 (November 15, 2021): 6888. http://dx.doi.org/10.3390/ma14226888.
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Various COx species formed upon the adsorption and oxidation of CO on palladium and silver single atoms supported on a model ceria nanoparticle (NP) have been studied using density functional calculations. For both metals M, the ceria-supported MCOx moieties are found to be stabilised in the order MCO < MCO2 < MCO3, similar to the trend for COx species adsorbed on M-free ceria NP. Nevertheless, the characteristics of the palladium and silver intermediates are different. Very weak CO adsorption and the small exothermicity of the CO to CO2 transformation are found for O4Pd site of the Pd/Ce21O42 model featuring a square-planar coordination of the Pd2+ cation. The removal of one O atom and formation of the O3Pd site resulted in a notable strengthening of CO adsorption and increased the exothermicity of the CO to CO2 reaction. For the analogous ceria models with atomic Ag instead of atomic Pd, these two energies became twice as small in magnitude and basically independent of the presence of an O vacancy near the Ag atom. CO2-species are strongly bound in palladium carboxylate complexes, whereas the CO2 molecule easily desorbs from oxide-supported AgCO2 moieties. Opposite to metal-free ceria particle, the formation of neither PdCO3 nor AgCO3 carbonate intermediates before CO2 desorption is predicted. Overall, CO oxidation is concluded to be more favourable at Ag centres atomically dispersed on ceria nanostructures than at the corresponding Pd centres. Calculated vibrational fingerprints of surface COx moieties allow us to distinguish between CO adsorption on bare ceria NP (blue frequency shifts) and ceria-supported metal atoms (red frequency shifts). However, discrimination between the CO2 and CO32− species anchored to M-containing and bare ceria particles based solely on vibrational spectroscopy seems problematic. This computational modelling study provides guidance for the knowledge-driven design of more efficient ceria-based single-atom catalysts for the environmentally important CO oxidation reaction.
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Schultz, Olaf. "Agco startet stark in die Saison." agrarzeitung 76, no. 18 (2021): 8. http://dx.doi.org/10.51202/1869-9707-2021-18-008-2.
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Grimm, Alice M., A. K. Sahai, and Chester F. Ropelewski. "Interdecadal Variations in AGCM Simulation Skills." Journal of Climate 19, no. 14 (July 15, 2006): 3406–19. http://dx.doi.org/10.1175/jcli3803.1.
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Abstract Global climate models forced by sea surface temperature are standard tools in seasonal climate prediction and in projection of future climate change caused by anthropogenic emissions of greenhouse gases. Assessing the ability of these models to reproduce observed atmospheric circulation given the lower boundary conditions, and thus its ability to predict climate, has been a recurrent concern. Several assessments have shown that the performance of models is seasonally dependent, but there has always been the assumption that, for a given season, the model skill is constant throughout the period being analyzed. Here, it is demonstrated that there are periods when these models perform well and periods when they do not capture observed climate variability. The variations of the model performance have temporal scales and spatial patterns consistent with decadal/interdecadal climate variability. These results suggest that there are unmodeled climate processes that affect seasonal climate prediction as well as scenarios of climate change, particularly regional climate change projections. The reliability of these scenarios may depend on the time slice of the model output being analyzed. Therefore, more comprehensive model assessment should include a verification of the long-term stability of their performance.
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Pisov, Stoyan, Oksana Melikhova, and Marc Hou. "Mechanical properties of AgCo nanostructured nanowires." Computer Physics Communications 179, no. 1-3 (July 2008): 102–6. http://dx.doi.org/10.1016/j.cpc.2008.01.016.
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Molod, Andrea. "Constraints on the Profiles of Total Water PDF in AGCMs from AIRS and a High-Resolution Model." Journal of Climate 25, no. 23 (December 1, 2012): 8341–52. http://dx.doi.org/10.1175/jcli-d-11-00412.1.
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Abstract Atmospheric general circulation model (AGCM) cloud parameterizations generally include an assumption about the subgrid-scale probability distribution function (PDF) of total water and its vertical profile. In the present study, the Atmospheric Infrared Sounder (AIRS) monthly-mean cloud amount and relative humidity fields are used to compute a proxy for the second moment of an AGCM total water PDF called the “RH01 diagnostic,” which is the AIRS mean relative humidity for cloud fractions of 0.1 or less. The dependence of the second moment on horizontal grid resolution is analyzed using results from a high-resolution global model simulation. The AIRS-derived RH01 diagnostic is generally larger near the surface than aloft, indicating a narrower PDF near the surface, and varies with the type of underlying surface. High-resolution model results show that the vertical structure of profiles of the AGCM PDF second moment is unchanged as the grid resolution changes from 200 to 100 to 50 km, and that the second-moment profiles shift toward higher values with decreasing grid spacing. Several Goddard Earth Observing System, version 5 (GEOS-5), AGCM simulations were performed with several choices for the profile of the PDF second moment. The resulting cloud and relative humidity fields were shown to be quite sensitive to the prescribed profile, and the use of a profile based on the AIRS-derived proxy results in improvements relative to observational estimates. The AIRS-guided total water PDF profiles, including their dependence on underlying surface type and on horizontal resolution, have been implemented in the version of the GEOS-5 AGCM used for publicly released simulations.
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Dong, Buwen, Rowan T. Sutton, Len Shaffrey, and Nicholas P. Klingaman. "Attribution of Forced Decadal Climate Change in Coupled and Uncoupled Ocean–Atmosphere Model Experiments." Journal of Climate 30, no. 16 (August 2017): 6203–23. http://dx.doi.org/10.1175/jcli-d-16-0578.1.
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There is still no consensus about the best methodology for attributing observed changes in climate or climate events. One widely used approach relies on experiments in which the time periods of interest are simulated using an atmospheric general circulation model (AGCM) forced by prescribed sea surface temperatures (SSTs), with and without estimated anthropogenic influences. A potential limitation of such experiments is the lack of explicit atmosphere–ocean coupling; therefore a key question is whether the attribution statements derived from such studies are in fact robust. In this research the authors have carried out climate model experiments to test attribution conclusions in a situation where the answer is known—a so-called perfect model approach. The study involves comparing attribution conclusions for decadal changes derived from experiments with a coupled climate model (specifically an AGCM coupled to an ocean mixed-layer model) with conclusions derived from parallel experiments with the same AGCM forced by SSTs derived from the coupled model simulations. Results indicate that attribution conclusions for surface air temperature changes derived from AGCM experiments are generally robust and not sensitive to air–sea coupling. However, changes in seasonal mean and extreme precipitations, and circulation in some regions, show large sensitivity to air–sea coupling, notably in the summer monsoons over East Asia and Australia. Comparison with observed changes indicates that the coupled simulations generally agree better with observations. These results demonstrate that the AGCM-based attribution method has limitations and may lead to erroneous attribution conclusions in some regions for local circulation and mean and extreme precipitation. The coupled mixed-layer model used in this study offers an alternative and, in some respects, superior tool for attribution studies.
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Kumar, Arun, Qin Zhang, J.-K. E. Schemm, Michelle L’Heureux, and K.-H. Seo. "An Assessment of Errors in the Simulation of Atmospheric Interannual Variability in Uncoupled AGCM Simulations." Journal of Climate 21, no. 10 (May 15, 2008): 2204–17. http://dx.doi.org/10.1175/2007jcli1743.1.
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Abstract For the uncoupled atmospheric general circulation model (AGCM) simulations, the quantification of errors due to the lack of coupled ocean–atmospheric evolution on the characteristics of the atmospheric interannual variability is important for various reasons including the following: 1) AGCM simulations forced with specified SSTs continue to be used for understanding atmospheric interannual variability and 2) there is a vast knowledge base quantifying the global atmospheric influence of tropical SSTs that traditionally has relied on the analysis of AGCM-alone simulations. To put such results and analysis in a proper context, it is essential to document errors that may result from the lack of a coupled ocean–atmosphere evolution in the AGCM-alone integrations. Analysis is based on comparison of tier-two (or uncoupled) and coupled hindcasts for the 1982–2005 period, and interannual variability for the December–February (DJF) seasonal mean is analyzed. Results indicate that for the seasonal mean variability, and for the DJF seasonal mean, atmospheric interannual variability between coupled and uncoupled simulations is similar. This conclusion is drawn from the analysis of interannual variability of rainfall and 200-mb heights and includes analysis of SST-forced interannual variability, analysis of El Niño and La Niña composites, and a comparison of hindcast skill between tier-two and coupled hindcasts.
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Zheng, Y., D. E. Waliser, W. F. Stern, and C. Jones. "The Role of Coupled Sea Surface Temperatures in the Simulation of the Tropical Intraseasonal Oscillation." Journal of Climate 17, no. 21 (November 1, 2004): 4109–34. http://dx.doi.org/10.1175/jcli3202.1.
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Abstract This study compares the tropical intraseasonal oscillation (TISO) variability in the Geophysical Fluid Dynamics Laboratory (GFDL) coupled general circulation model (CGCM) and the stand-alone atmospheric general circulation model (AGCM). For the AGCM simulation, the sea surface temperatures (SSTs) were specified using those from the CGCM simulation. This was done so that any differences in the TISO that emerged from the two simulations could be attributed to the coupling process and not to a difference in the mean background state. The comparison focused on analysis of the rainfall, 200-mb velocity potential, and 850-mb zonal wind data from the two simulations, for both summer and winter periods, and included comparisons to analogous diagnostics using NCEP–NCAR reanalysis and Climate Prediction Center (CPC) Merged Analysis of Precipitation (CMAP) rainfall data. The results of the analysis showed three principal differences in the TISO variability between the coupled and uncoupled simulations. The first was that the CGCM showed an improvement in the spatial variability associated with the TISO mode, particularly for boreal summer. Specifically, the AGCM exhibited almost no TISO variability in the Indian Ocean during boreal summer—a common shortcoming among AGCMs. The CGCM, on the other hand, did show a considerable enhancement in TISO variability in this region for this season. The second was that the wavenumber–frequency spectra of the AGCM exhibited an unrealistic peak in variability at low wavenumbers (1–3, depending on the variable) and about 3 cycles yr−1 (cpy). This unrealistic peak of variability was absent in the CGCM, which otherwise tended to show good agreement with the observations. The third difference was that the AGCM showed a less realistic phase lag between the TISO-related convection and SST anomalies. In particular, the CGCM exhibited a near-quadrature relation between precipitation and SST anomalies, which is consistent with observations, while the phase lag was reduced in the AGCM by about 1.5 pentads (∼1 week). The implications of the above results, including those for the notions of “perfect SST” and “two tier” experiments, are discussed, as are the caveats associated with the study's modeling framework and analysis.
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Santos, A. F., A. M. Mendonça, J. P. Bonatti, J. G. Z. de Mattos, P. Y. Kubota, S. R. Freitas, M. A. F. Silva Dias, E. Ramirez, and R. Camayo. "Evaluation of the CPTEC/AGCM wind forecasts during the hurricane Catarina occurrence." Advances in Geosciences 14 (May 7, 2008): 317–26. http://dx.doi.org/10.5194/adgeo-14-317-2008.
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Abstract. In March 2004 occurred the first hurricane registered at South Atlantic Ocean. The system named Catarina begun as an extratropical cyclone and remained quasi-stationary some days over the South Atlantic Ocean. The system displaced westward, acquiring characteristics of a hurricane and hit the Brazilian State of Santa Catarina (SC) between the 27 and the 28 March, causing destruction and deaths. The objective of this paper is to evaluate the Center for Weather Prediction and Climate Studies, Atmospheric Global Circulation Model (CPTEC/AGCM) forecast performance of some synoptic patterns associated with Catarina. The surface wind and reduced Sea Level Pressure (SLP) were examined. Moreover, the implementation of 10-m wind forecast (V10m) was evaluated. This variable was not available in the CPTEC/AGCM during the Catarina occurrence and in this study it was compared with the wind at first sigma-level of the AGCM. The CPTEC-Eta reanalyses were used to comparisons. According to reanalyses, more intense winds were observed in northeast, south and southwest edges of the cyclone. The system was not predicted by the CPTEC/AGCM forecasts longer than 24 h, then the analyses were carried out only for 24 h forecasts. In general, the first sigma-level wind forecasts underestimated the wind magnitude and the cyclone intensity. However, the Catarina formation and its displacement southeastward between the 20 and the 21 March were well represented by the model. The CPTEC/AGCM presents deficiencies to predict the system intensity, but in short-range forecasts it was possible to predict the system formation and its atypical trajectory. The wind results from the new implementation did not exhibit better performance compared with the wind at first sigma-level. These results will be better investigated in the future.
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Gritsun, Andrey, and Grant Branstator. "Climate Response Using a Three-Dimensional Operator Based on the Fluctuation–Dissipation Theorem." Journal of the Atmospheric Sciences 64, no. 7 (July 1, 2007): 2558–75. http://dx.doi.org/10.1175/jas3943.1.
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Abstract The fluctuation–dissipation theorem (FDT) states that for systems with certain properties it is possible to generate a linear operator that gives the response of the system to weak external forcing simply by using covariances and lag-covariances of fluctuations of the undisturbed system. This paper points out that the theorem can be shown to hold for systems with properties very close to the properties of the earth’s atmosphere. As a test of the theorem’s applicability to the atmosphere, a three-dimensional operator for steady responses to external forcing is constructed for data from an atmospheric general circulation model (AGCM). The response of this operator is then compared to the response of the AGCM for various heating functions. In most cases, the FDT-based operator gives three-dimensional responses that are very similar in structure and amplitude to the corresponding GCM responses. The operator is also able to give accurate estimates for the inverse problem in which one derives the forcing that will produce a given response in the AGCM. In the few cases where the operator is not accurate, it appears that the fact that the operator was constructed in a reduced space is at least partly responsible. As an example of the potential utility of a response operator with the accuracy found here, the FDT-based operator is applied to a problem that is difficult to solve with an AGCM. It is used to generate an influence function that shows how well heating at each point on the globe excites the AGCM’s Northern Hemisphere annular mode (NAM). Most of the regions highlighted by this influence function, including the Arctic and tropical Indian Ocean, are verified by AGCM solutions as being effective locations for stimulating the NAM.
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Mahanama, Sarith P. P., and Randal D. Koster. "AGCM Biases in Evaporation Regime: Impacts on Soil Moisture Memory and Land–Atmosphere Feedback." Journal of Hydrometeorology 6, no. 5 (October 1, 2005): 656–69. http://dx.doi.org/10.1175/jhm446.1.
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Abstract Because precipitation and net radiation in an atmospheric general circulation model (AGCM) are typically biased relative to observations, the simulated evaporative regime of a region may be biased, with consequent negative effects on the AGCM’s ability to translate an initialized soil moisture anomaly into an improved seasonal prediction. These potential problems are investigated through extensive offline analyses with the Mosaic land surface model (LSM). The LSM was first forced globally with a 15-yr observation-based dataset. The simulation was then repeated after imposing a representative set of GCM climate biases onto the forcings—the observational forcings were scaled so that their mean seasonal cycles matched those simulated by the NASA Seasonal-to-Interannual Prediction Project (NSIPP-1; NASA Global Modeling and Assimilation Office) AGCM over the same period. The AGCM’s climate biases do indeed lead to significant biases in evaporative regime in certain regions, with the expected impacts on soil moisture memory time scales. Furthermore, the offline simulations suggest that the biased forcing in the AGCM should contribute to overestimated feedback in certain parts of North America—parts already identified in previous studies as having excessive feedback. The present study thus supports the notion that the reduction of climate biases in the AGCM will lead to more appropriate translations of soil moisture initialization into seasonal prediction skill.
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Nober, F. J., and H. F. Graf. "A new convective cloud field model based on principles of self-organisation." Atmospheric Chemistry and Physics Discussions 4, no. 4 (July 1, 2004): 3669–98. http://dx.doi.org/10.5194/acpd-4-3669-2004.
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Abstract. A new cumulus convection parameterisation is presented in this paper. The parameterisation uses an explicit spectral approach and determines, unlike other convection schemes, for each convection event a new cloud distribution function regarding to the given vertical temperature and humidity profiles. This is done by using a one-dimensional cloud model to create a spectrum of different clouds. The interaction between all non convective physical processes in the AGCM and all different clouds is taken into account to calculate a self consistent cloud spectrum. The model has been implemented in the ECHAM5 AGCM and tested against a large eddy simulation model. The representation of a shallow cumulus cloud field by the AGCM could be much improved. Diurnal cycle, cloud cover, liquid water path and the vertical structure of the mass flux, determined by the new convection scheme are close to the large eddy simulation, whereas the standard convection scheme failed in simulating this convection episode.
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Nober, F. J., and H. F. Graf. "A new convective cloud field model based on principles of self-organisation." Atmospheric Chemistry and Physics 5, no. 10 (October 20, 2005): 2749–59. http://dx.doi.org/10.5194/acp-5-2749-2005.
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Abstract. A new cumulus convection parameterisation is presented in this paper. The parameterisation uses an explicit spectral approach and determines, unlike other convection schemes, for each convection event a new cloud distribution function regarding to the given vertical temperature and humidity profiles. This is done by using a one dimensional cloud model to create a spectrum of different clouds. The interaction between all non convective physical processes in the AGCM and all different clouds is taken into account to calculate a selfconsistent cloud spectrum. The model has been implemented in the ECHAM5 AGCM and tested against a large eddy simulation model. The representation of a shallow cumulus cloud field by the AGCM could be much improved. Diurnal cycle, cloud cover, liquid water path and the vertical structure of the mass flux, determined by the new convection scheme are close to the large eddy simulation, whereas the standard convection scheme failed in simulating this convection episode.
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Souza, Jocely Gomes de, and Claudio Vaz Di Mambro Ribeiro. "Biohidrogenação ruminal e os principais impactos no perfil de ácidos graxos da carne: revisão." Research, Society and Development 10, no. 13 (October 3, 2021): e28101321039. http://dx.doi.org/10.33448/rsd-v10i13.21039.
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Na carne e leite de ruminantes, o perfil dos ácidos graxos (AG) se diferencia pelo maior teor do ácido linoleico conjugado (CLA), molécula com propriedades bioativas. O presente trabalho foi realizado por busca bibliográfica com os objetivos de descrever o processo de BH com suas principias rotas e descrever os principais efeitos da suplementação de lipídios no perfil de AG da carne de ruminantes, ressaltando os potenciais efeitos dos AG de cadeia média (AGCM). O processo de biohidrogenação (BH) ruminal é responsável pela síntese da CLA, e sua manipulação é o foco de muitas pesquisas que tentam aumentar os AG benéficos nos produtos de ruminantes. Com a inibição da BH, aumenta-se o teor de CLA sendo absorvido pelo duodeno. Para tanto, o uso de fontes de AG insaturados e AGCM tem sido estudado. No entanto, existem poucas pesquisas sobre o efeito dos AGCM na BH. Esse AG têm o potencial para aumentar a fluidez das membranas de bactérias gram-positivas, tornando-as ineficientes, diminuindo sua atividade, o que ocasiona uma redução da segunda etapa da BH e, como consequência, um acúmulo do CLA no rúmen. Como fontes principais de AGCM, destacam-se apenas o óleo de coco, dendê e licuri. Mais pesquisas são necessárias para entendermos como elas se comparam a outros métodos de manipulação ruminal e eficiência de melhorar a qualidade dos produtos de ruminantes para o consumo humano, com foco no perfil de AG.
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Feng, Xia, Timothy DelSole, and Paul Houser. "Comparison of Seasonal Potential Predictability of Precipitation." Journal of Climate 27, no. 11 (May 29, 2014): 4094–110. http://dx.doi.org/10.1175/jcli-d-13-00489.1.
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Abstract Three methods for estimating potential seasonal predictability of precipitation from a single realization of daily data are assessed. The estimation methods include a first-order Markov chain model proposed by Katz (KZ), and an analysis of covariance (ANOCOVA) method and a bootstrap method proposed by the authors. The assessment is based on Monte Carlo experiments, ensemble atmospheric general circulation model (AGCM) simulations, and observation-based data. For AGCM time series, ANOCOVA produces the most accurate estimates of weather noise variance, despite the fact that it makes the most unrealistic assumptions about precipitation (in particular, it assumes precipitation is generated by a Gaussian autoregressive model). The KZ method significantly underestimates noise variance unless the autocorrelation of precipitation amounts on consecutive wet days is taken into account. Both AGCM and observation-based data reveal that the fraction of potentially predictable variance is greatest in the tropics, smallest in the extratropics, and undergoes a strong seasonal variation. The three methods give consistent estimates of potential predictability for 67% of the globe.
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Wang, Zhuo, and C.-P. Chang. "Mechanism of the Asymmetric Monsoon Transition as Simulated in an AGCM." Journal of Climate 21, no. 8 (April 15, 2008): 1829–36. http://dx.doi.org/10.1175/2007jcli1920.1.
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Abstract Atmospheric general circulation model (AGCM) simulations are carried out to test a hypothesis (Chang et al.) for the asymmetric monsoon transition in which the maximum convection marches gradually from the Asian summer monsoon to the Asian winter monsoon during boreal fall but experiences a sudden transition in the reverse during boreal spring. In the control run, the AGCM is driven by the climatological mean sea surface temperature (SST) with a realistic annual cycle, and it reproduces the observed asymmetric monsoon transition. In the sensitivity test, the model is driven by a similarly realistic SST but whose annual cycle is symmetric. The northwestward march of the maximum convection in boreal spring becomes more gradual, resulting in an overall near-symmetric pattern for the monsoon seasonal transition. The AGCM simulations confirm the hypothesis that the atmospheric mass redistribution due to the different land–ocean thermal memories leads to a seasonally different horizontal convergence field and it facilitates the southeastward monsoon march in boreal fall, while it hinders the northwestward monsoon march in boreal spring, contributing to the asymmetric monsoon transition.
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Misra, Vasubandhu. "The Influence of Pacific SST Variability on the Precipitation over Southern Africa." Journal of Climate 16, no. 14 (July 15, 2003): 2408–18. http://dx.doi.org/10.1175/2785.1.
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Abstract This study is an analysis of AGCM model results to understand the dynamics of the response of precipitation over southern Africa (SA) to anomalies in the sea surface temperature (SST) over the Pacific Ocean. The pattern of interannual precipitation anomaly over SA and its temporal variations are quite similar in both the ensemble mean of the control (where AGCM is forced with observed SSTs in all ocean basins) and experimental runs (where AGCM is forced with seasonally varying climatological SST over the Pacific Ocean). However, the amplitude of the variability is found to be relatively reduced in the experimental runs. This is shown to be a result of the modulation of the Walker circulation by the variability of Pacific Ocean SST. The regional teleconnection pattern between the dominant mode of SA precipitation variability and SST anomalies over the eastern Indian Ocean is also influenced by the variations in Pacific SST. The nature of the teleconnection between SA precipitation and eastern Indian SST is apparent only when the Pacific SST variability is excluded. This is corroborated from observations as well.
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-. "AGCO renovates the line of Challenger combines." Traktory i sel hozmashiny 79, no. 7 (July 15, 2012): 18. http://dx.doi.org/10.17816/0321-4443-69437.
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Carey, M. J., A. P. Young, A. Starr, D. Rao, and A. E. Berkowitz. "Giant magnetoresistance in heterogeneous AgCo alloy films." Applied Physics Letters 61, no. 24 (December 14, 1992): 2935–37. http://dx.doi.org/10.1063/1.108027.
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Biasutti, M., A. H. Sobel, and Y. Kushnir. "AGCM Precipitation Biases in the Tropical Atlantic." Journal of Climate 19, no. 6 (March 15, 2006): 935–58. http://dx.doi.org/10.1175/jcli3673.1.
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Abstract Many general circulation models (GCMs) share similar biases in the representation of the intertropical convergence zone (ITCZ) in the Atlantic, even when they are forced with the time series of the observed sea surface temperature (SST). Specifically, they overestimate precipitation in the Southern Hemisphere in boreal spring and in the Caribbean region in boreal summer. The majority of the models considered here place the rainfall maximum over the SST maximum, although the true precipitation maximum does not occur there. This is the case even though these GCMs accurately place the maximum in surface wind convergence away from the SST maximum, at the location where the observed precipitation maximum lies. Models that overrespond to SST in this way tend to (i) have fewer heavy-rain events, (ii) rain more for a smaller amount of water vapor in the atmospheric column, and (iii) couple rainfall and surface humidity too strongly and rainfall and humidity above the surface too weakly.
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Taschetto, A. S., and M. H. England. "Estimating ensemble size requirements of AGCM simulations." Meteorology and Atmospheric Physics 100, no. 1-4 (August 2008): 23–36. http://dx.doi.org/10.1007/s00703-008-0293-8.
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Lorenz, T., M. Moske, H. Geisler, R. V. Helmolt, M. Weiβ, and K. Samwer. "Magnetization and magnetoresistance in granular AgCo films." Thin Solid Films 275, no. 1-2 (April 1996): 220–23. http://dx.doi.org/10.1016/0040-6090(95)07048-6.
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Shimura, Tomoya, Nobuhito Mori, Daisuke Urano, Tetsuya Takemi, and Ryo Mizuta. "Tropical Cyclone Characteristics Represented by the Ocean Wave-Coupled Atmospheric Global Climate Model Incorporating Wave-Dependent Momentum Flux." Journal of Climate 35, no. 2 (January 15, 2022): 499–515. http://dx.doi.org/10.1175/jcli-d-21-0362.1.
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Abstract Understanding the systematic characteristics of tropical cyclones (TCs) represented in global climate models (GCMs) is important for reliable climate change impact assessments. The atmospheric GCM (AGCM) and ocean wave models were coupled by incorporating the wave-dependent momentum flux. Systematic impacts of wave-dependent momentum flux on TC characteristics were estimated by analyzing 100 historical TCs that occurred in the western North Pacific Ocean. Wave-dependent momentum flux parameterization considering wind and wave direction misalignment was used for assessing the wave–atmosphere interaction. The larger the wave age and misalignment are, the larger the drag coefficient is. The drag coefficient at the left-hand side of the TC was enhanced by the wave condition. It was found that the wave-dependent momentum flux did not have any impact on peak TC intensity. On the other hand, the wave-dependent momentum flux showed a significant impact on TC development during the early development stage. Although systematic differences in TC intensity at most developed stages were not detected, systematic differences in TC tracks between experiments were observed. The TC tracks of the wave-coupled AGCM tend to pass in a relatively eastward direction in comparison with those from the uncoupled AGCM. This is because the wave-dependent momentum flux in the coupled AGCM altered the environmental steering flow and the smaller beta effect of smaller TC at the early developing stage. Systematic differences in TC tracks have significant impacts on climate change assessments, such as extreme sea level changes in coastal regions due to climate change.
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Okajima, Satoru, Hisashi Nakamura, Kazuaki Nishii, Takafumi Miyasaka, and Akira Kuwano-Yoshida. "Assessing the Importance of Prominent Warm SST Anomalies over the Midlatitude North Pacific in Forcing Large-Scale Atmospheric Anomalies during 2011 Summer and Autumn." Journal of Climate 27, no. 11 (May 29, 2014): 3889–903. http://dx.doi.org/10.1175/jcli-d-13-00140.1.
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Abstract Sets of atmospheric general circulation model (AGCM) experiments are conducted to assess the importance of prominent positive anomalies in sea surface temperature (SST) observed over the midlatitude North Pacific in forcing a persistent basin-scale anticyclonic circulation anomaly and its downstream influence in 2011 summer and autumn. The anticyclonic anomaly observed in October is well reproduced as a robust response of an AGCM forced only with the warm SST anomaly associated with the poleward-shifted oceanic frontal zone in the midlatitude Pacific. The equivalent barotropic anticyclonic anomaly over the North Pacific is maintained under strong transient eddy feedback forcing associated with the poleward-deflected storm track. As the downstream influence of the anomaly, abnormal warmth and dryness observed over the northern United States and southern Canada in October are also reproduced to some extent. The corresponding AGCM response over the North Pacific to the tropical SST anomalies is similar but substantially weaker and less robust, suggesting the primary importance of the prominent midlatitude SST anomaly in forcing the large-scale atmospheric anomalies observed in October 2011. In contrast, the model reproduction of the atmospheric anomalies observed in summer was unsuccessful. This appears to arise from the fact that, unlike in October, the midlatitude SST anomalies accompanied reduction of heat and moisture release from the ocean, indicative of the atmospheric thermodynamic forcing on the SST anomalies. Furthermore, the distinct seasonality in the AGCM responses to the warm SST anomalies may also be contributed to by the seasonality of background westerlies and storm track.
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Misra, Vasubandhu. "Simulation of the Intraseasonal Variance of the South American Summer Monsoon." Monthly Weather Review 133, no. 3 (March 1, 2005): 663–76. http://dx.doi.org/10.1175/mwr-2877.1.
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Abstract This study reveals the inadequacy of the Center for Ocean–Land–Atmosphere Studies (COLA) atmospheric general circulation model (AGCM) and the National Centers for Environmental Prediction–National Center for Atmospheric Research (NCEP–NCAR) reanalysis to resolve the variance of the intraseasonal anomalies of outgoing longwave radiation (OLR) over the South American summer monsoon (SASM) domain and the equatorial eastern Pacific Ocean (EEPO) owing to their coarse horizontal resolution. However, when the NCEP–NCAR reanalysis is downscaled by roughly a factor of 2.5 using the Regional Spectral Model (RSM; control-A experiment), the simulation of the seasonal mean variance of intraseasonal anomalies of OLR improves significantly. But downscaling the results of the COLA AGCM (control-B experiment) by roughly a factor of 4 led to no further improvement. Using the novel technique of anomaly nesting, which replaces the climatology of the COLA AGCM of the nested variables at the lateral boundaries of the RSM with the NCEP–NCAR reanalysis climatology (AN experiment), the simulation of the intraseasonal variance of OLR improves significantly over control-B runs. This improvement is shown to coincide with a distinct diurnal variation of the intraseasonal scales displayed in the AN integrations, which compare reasonably well with control-A integrations. A disappointing result of this study is that the generated variance of intraseasonal anomalies of OLR in the AN integrations arises from the internal variability of the model. However, it is concluded that the systematic errors of the COLA AGCM imposed on RSM from the lateral boundary conditions suppress the generation of intraseasonal variability.
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Schultz, Olaf. "Deutz setzt auf Wasserstoffmotoren für Landmaschinen." agrarzeitung 76, no. 33 (2021): 8. http://dx.doi.org/10.51202/1869-9707-2021-33-008.
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Ma, Xiaowei, Yue Guo, Jing Jin, Bing Zhao, and Wei Song. "Bi-functional reduced graphene oxide/AgCo composite nanosheets: an efficient catalyst and SERS substrate for monitoring the catalytic reactions." RSC Advances 7, no. 67 (2017): 41962–69. http://dx.doi.org/10.1039/c7ra07216c.
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Molod, A., L. Takacs, M. Suarez, and J. Bacmeister. "Development of the GEOS-5 atmospheric general circulation model: evolution from MERRA to MERRA2." Geoscientific Model Development 8, no. 5 (May 12, 2015): 1339–56. http://dx.doi.org/10.5194/gmd-8-1339-2015.
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Abstract. The Modern-Era Retrospective Analysis for Research and Applications-2 (MERRA2) version of the Goddard Earth Observing System-5 (GEOS-5) atmospheric general circulation model (AGCM) is currently in use in the NASA Global Modeling and Assimilation Office (GMAO) at a wide range of resolutions for a variety of applications. Details of the changes in parameterizations subsequent to the version in the original MERRA reanalysis are presented here. Results of a series of atmosphere-only sensitivity studies are shown to demonstrate changes in simulated climate associated with specific changes in physical parameterizations, and the impact of the newly implemented resolution-aware behavior on simulations at different resolutions is demonstrated. The GEOS-5 AGCM presented here is the model used as part of the GMAO MERRA2 reanalysis, global mesoscale simulations at 10 km resolution through 1.5 km resolution, the real-time numerical weather prediction system, and for atmosphere-only, coupled ocean-atmosphere and coupled atmosphere-chemistry simulations. The seasonal mean climate of the MERRA2 version of the GEOS-5 AGCM represents a substantial improvement over the simulated climate of the MERRA version at all resolutions and for all applications. Fundamental improvements in simulated climate are associated with the increased re-evaporation of frozen precipitation and cloud condensate, resulting in a wetter atmosphere. Improvements in simulated climate are also shown to be attributable to changes in the background gravity wave drag, and to upgrades in the relationship between the ocean surface stress and the ocean roughness. The series of resolution-aware parameters related to the moist physics was shown to result in improvements at higher resolutions and result in AGCM simulations that exhibit seamless behavior across different resolutions and applications.
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Sud, Y. C., D. Lee, L. Oreopoulos, D. Barahona, A. Nenes, and M. J. Suarez. "Performance of McRAS-AC in the GEOS-5 AGCM: aerosol-cloud-microphysics, precipitation, cloud radiative effects, and circulation." Geoscientific Model Development Discussions 5, no. 2 (June 8, 2012): 1381–434. http://dx.doi.org/10.5194/gmdd-5-1381-2012.
Full textAbstract:
Abstract. A revised version of the Microphysics of clouds with Relaxed Arakawa-Schubert and Aerosol-Cloud interaction scheme (McRAS-AC) including, among others, the Barahona and Nenes ice nucleation parameterization, is implemented in the GEOS-5 AGCM. Various fields from a 10-yr long integration of the AGCM with McRAS-AC were compared with their counterparts from an integration of the baseline GEOS-5 AGCM using satellite data as observations. Generally McRAS-AC simulations have smaller biases in cloud fields and cloud radiative effects over most of the regions of the Earth than the baseline GEOS-5 AGCM. Two systematic biases are identified in the McRAS-AC runs: one under-prediction of cloud particles around 40° S–60° S, and one over-prediction of cloud water path during Northern Hemisphere summer over the Gulf Stream and North Pacific. Sensitivity analyses show that these biases potentially originate from biases in the aerosol input. The first bias is largely eliminated in a sensitivity test using 50% smaller sea-salt aerosol particles, while the second bias is much reduced when interactive aerosol chemistry was turned on. The main drawback of McRAS-AC is dearth of low-level marine stratus clouds, probably due to lack of boundary-layer clouds that is an outcome of explicit dry-convection not yet implemented into the cloud model. Nevertheless, McRAS-AC simulates realistic clouds and their optical properties that can further improve with better aerosol-input. Thereby, McRAS-AC has the potential to be a valuable tool for climate modeling research because of its superior simulation capabilities that physically couple aerosols, cloud microphysics, cloud macrophysics, and cloud-radiation interaction for all clouds.
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Molod, A., L. Takacs, M. Suarez, and J. Bacmeister. "Development of the GEOS-5 atmospheric general circulation model: evolution from MERRA to MERRA2." Geoscientific Model Development Discussions 7, no. 6 (November 13, 2014): 7575–617. http://dx.doi.org/10.5194/gmdd-7-7575-2014.
Full textAbstract:
Abstract. The Modern-Era Retrospective Analysis for Research and Applications-2 (MERRA2) version of the GEOS-5 Atmospheric General Circulation Model (AGCM) is currently in use in the NASA Global Modeling and Assimilation Office (GMAO) at a wide range of resolutions for a variety of applications. Details of the changes in parameterizations subsequent to the version in the original MERRA reanalysis are presented here. Results of a series of atmosphere-only sensitivity studies are shown to demonstrate changes in simulated climate associated with specific changes in physical parameterizations, and the impact of the newly implemented resolution-aware behavior on simulations at different resolutions is demonstrated. The GEOS-5 AGCM presented here is the model used as part of the GMAO's MERRA2 reanalysis, the global mesoscale "nature run", the real-time numerical weather prediction system, and for atmosphere-only, coupled ocean–atmosphere and coupled atmosphere–chemistry simulations. The seasonal mean climate of the MERRA2 version of the GEOS-5 AGCM represents a substantial improvement over the simulated climate of the MERRA version at all resolutions and for all applications. Fundamental improvements in simulated climate are associated with the increased re-evaporation of frozen precipitation and cloud condensate, resulting in a wetter atmosphere. Improvements in simulated climate are also shown to be attributable to changes in the background gravity wave drag, and to upgrades in the relationship between the ocean surface stress and the ocean roughness. The series of "resolution aware" parameters related to the moist physics were shown to result in improvements at higher resolutions, and result in AGCM simulations that exhibit seamless behavior across different resolutions and applications.