Sufficiency Index Research Articles

Chlorophyll meter‐based leaf nitrogen status to manage nitrogen in tropical potato production

AbstractPotato (Solanum tuberosum L.) is a N intensive crop, and meeting its requirements with N fertilization is the primary practice to improve N recovery and achieve suitable tuber yield. A 3‐site‐year (SY) study was conducted to assess soil plant analysis development (SPAD)‐502 chlorophyll meter efficacy for providing potato leaf real‐time N status to adjust N timing and rate using nitrogen sufficiency index (NSI) thresholds of 90 or 95%. We evaluated effects of in‐season SPAD‐based N managements, as well as a reference with non‐limiting N application, a fixed‐timing (planting and hilling) conventional N fertilization, and a zero‐N control on crop N uptake, tuber yield, and N‐use efficiency of potato cultivar Agata grown in tropical clay soils. Tuber yields were similar in both SPAD‐based managements. Under no intensive rainfall events after N applications, SPAD‐based managements reduced N applications by 38–63% and resulted in comparable tuber set, bulking, and yield relative to conventional N fertilization. Additionally, SPAD‐based management at a NSI threshold of 90% resulted in greater potato N‐uptake efficiency and tuber yield per unit of N applied. SPAD‐502 sensor was efficient for detecting plant N status when environmental conditions were more conducive for potato production and optimized N management by reducing application rates. However, with less favorable temperature and solar radiation for potato cultivation, and with intensive rainfall events following N application, SPAD readings did not guide to a proper N fertilization and resulted in reduced tuber yield. Therefore, under such conditions, a more accurate method for detecting plant N status should be used.

On sufficient topological indices conditions for properties of graphs

In this paper, we present sufficient conditions on eccentric connectivity index, eccentric distance sum and connective eccentricity index for graphs to be k-hamiltonian, k-edge-hamiltonian or k-path-coverable.

Effect of physicochemical characteristics on the use of clays from Kindia (Guinea) in ceramic compositions

AbstractTo evaluate their potential uses in ceramic compositions, two different types of abundant clays from Kindia (Guinea Conakry), denoted ABD and ARD, were characterized with the chemical and mineralogical compositions, the specific surface area, the plasticity index, the particle size distribution, and the thermal behavior. Kaolinite and muscovite are the main clay minerals that are identified. Besides, non‐plastic minerals are large amount of quartz with a small particles size, goethite, hematite, anatase, and a small quantity of gibbsite. The two clays have a high plasticity index that is consistent with the small particle size and the broad size distribution. During heating, the fluxing behavior of the two clays induces a significant densification that is favored by the muscovite mineral combined with the reactive fine quartz. Besides, the firing shrinkage is limited to values of 4.5% and 3.5% for ABD and ARD respectively. In the objective of manufacturing ceramics, the two clays present the required properties. They present a sufficient plastic index in the green state, and after firing they lead to dense ceramics with an interesting bright color. The limited firing shrinkage is favorable to maintain the dimensional stability of vitrified ceramics as porcelain.

Critical concentration and management of nitrogen fertilization in the establishment of Brachiaria hybrid Mavuno

The critical range of leaf nitrogen (%NLeaf) concentration can be used to monitor the plant’s nitrogen (N) status, being an essential tool to define strategic fertilization protocols, where the time and amounts of fertilizers are applied according to pasture’s demand. The productivity parameters and two methods to determine N sufficiency – (i) the N nutrition index (NNI) and (ii) the normalized N sufficiency index (NSI) – were evaluated in Brachiaria hybrid Mavuno (Brachiaria spp. Syn. Urochloa spp.) along the regrowth cycles of the first growth season after seeding (establishment phase). The aims of the study were to estimate the critical %NLeaf for Mavuno grass pastures through productivity parameters, considering the sampling of the youngest expanded leaf as reference. Fertilization rates were defined as follow: no-nitrogen (N0), 15 (N15), 30 (N30) and 45 (N45) kg ha-1 of N and were applied after each cutting. The Falker chlorophyll index (FCI) was obtained from a portable chlorophyll meter Falker ClorofiLOG® CFL1030, and results were used to calculate the NSI. The regression analysis, on a regrowth cycle basis, provided the parameters to estimate the critical range of %NLeaf and the fertilization rates to attain the maximum forage accumulation. Population density of tiller was the main response contributing to increasing leaf and stem mass, leaf area index and forage accumulation as N fertilization increased. The FCI and NSI were unable to capture differences in %NLeaf, but NNI was a suitable tool to detect N status in Mavuno grass. The critical %NLeaf range varied from 2.75 to 3.07% and may be indicated to monitor pasture’s N status. The strategic N fertilization protocol suggested for the growth season after seeding is to apply 42.0 to 46.7 kg ha-1 of N at the first regrowth, 27.0 to 32.5 kg ha-1 of N during the two following regrowth cycles, whereas at the end of the season (April to May regrowth) only 22.2 to 24.7 kg ha-1 of N would be enough to sustain a maximum growth.

Validation of the Brazilian Portuguese version of Evidence-based Practice Knowledge Assessment in Nursing (EKAN).

The Evidence-based Practice Knowledge Assessment in Nursing (EKAN) is an objective measure of evidence-based practice (EBP) knowledge. The aims of the project were to translate the EKAN instrument into Brazilian Portuguese, test its psychometric properties, and document a baseline assessment of students' EBP knowledge. This study used methodological design. The EKAN-Brazilian Portuguese was administered to nursing students from two baccalaureate programs. Data were analyzed using Rasch procedures. 123 students participated (87% ranged 19-25 years old; 60% were juniors; 38% perceived having no exposure to EBP). Validity indices showed the mean difficulty index = -2.48 to 2.07, the Infit (WMS) mean was.985 (SD = 2.13), and the Outfit (UMS) mean was.975 (SD = 0.17). Reliability indices showed sufficient item separation index (4.47); moderate person separation index (.47); high item reliability (.95); and low person reliability (.18). The mean EKAN sum score (max = 20) was 7.6 (SD = 2.13). This study on the EKAN-Brazilian Portuguese version provided sufficient evidence for validity and reliability; the person reliabilities showed the need for improvement in incorporating EBP concepts and content in nursing programs.

INNOVATION AND INVESTMENT STRATEGIES FOR THE DEVELOPMENT OF TOURIST ENTERPRISES AS HOSPITALITY INDUSTRY SUBJECTS

Objective. Based on the integrated indicator of the intensity of the innovation strategy and the integrated indicator of the intensity of the investment strategy the objective of the article is to determine the innovation and investment strategy for the development of tourism enterprises as hospitality industry subjects. Methods. In the course of the research, the following methods are used: methods of theoretical generalization and comparison, analysis and synthesis (to determine the notion of the concept of “innovation and investment strategy”), index (to calculate the intensity of innovative and investment strategies using integrated indicators), matrix (to form a modi-fied GE / matrix McKinsey on the definition of innovative investment strategy of tourism enterprises). Results. Based on the study, a procedure for the integration of innovative and investment strategies of tourism enterprises, which involves comparing a separate type of innovative strategy (traditional, opportunistic, imitative, defense, offensive) with a separate type of investment strategy (preservation, accumulation, moderate growth, aggressive growth) is proposed. Based on these data, innovative investment strategies for tourism enterprises using the modified GE / McKinsey matrix (investment plateau, innovation breakthrough, innovation pole, innovation circuit, innovation springboard, innovation pit, innovation plateau) are offered. Using the index method, the intensity of the innovation and investment strategy is calculated as integral indicators, which consist of individual indicators of innovation (growth index of financial potential, growth index of material and technical potential, growth index of staff potential, growth index of marketing potential, growth index of information potential) and investment (index of growth of own investments, index of growth of attracted investments, index of growth of profit on own investments, index of growth of profit on attracted investments, index of sufficiency of investments) potentials. To determine the innovation and investment strategy for the development of tourism enterprises, a rating scale is developed for assessing the integral indicator of the intensity of the innovation strategy and the integrated indicator of the intensity of the investment strategy. Accordingly, innovation-investment strategies for the development of the tourism enterprises under study are identified. The positions of tourism enterprises in the modified GE / McKinsey matrix on the definition of an innovative investment strategy for the development of tourism enterprises are presented.

Fertilization factor associated with nitrogen sufficiency index for nitrogen topdressing fertilization in common bean

ABSTRACT The current recommendations for nitrogen (N) doses may not contemplate the complex dynamics of N in the soil, what may imply in insufficiency to the crop demand. This study aimed to evaluate the use of two portable chlorophyll meters (Minolta SPAD 502 and ClorofiLOG model CFL 1030), after defining the nitrogen sufficiency index (NSI), to estimate the nitrogen fertilization factor in modern bean genotypes. A block design was used, with four replications. Each experiment consisted of four treatments, with doses of 0, 5, 10 and 20 kg ha-1 of N for each 1 % considered below the NSI defined as adequate for each cultivar. At the end of the cycle, the production components and yield were evaluated. It was not possible to obtain precise adjustments in the methodology for the TAA Gol cultivar. The fertilization factor of 12.5 kg ha-1 of N for each 1 % below the NSI of 90 % proved to be efficient for the Pérola cultivar, when the SPAD-502 chlorophyll meter was used. In genotypes with size and cycle characteristics similar to those of the BRSMG Uai cultivar and the VR 20 strain, using a fertilization factor between 14 and 16 kg ha-1 of N, the NSI of 95 % must be reduced, in order to increase the efficiency of the nitrogen fertilization.

УНИКАЛЬНОСТЬ КОЛЛИЗИЙ В ТИПИЧНОМ СЦЕНАРИИ: ЯЗЫКОВАЯ ПОЛИТИКА РЕСПУБЛИКИ МОЛДОВА

The article is devoted to the formation and evolution of an independent language policy in the new post-Soviet sovereign states, each of which, despite similar processes, has its own specifics, due to both internal and external factors. The author focuses on the language policy in the Republic of Moldova, as stated in the language legislation, as well as on the extraordinary collisions that have arisen and are arising in dealing with language issues in this multi-ethnic republic during the 30 years of its independence. Since there are no special comprehensive studies on this topic at present, the article is an important attempt to give an analytical overview of language policy in the Republic of Moldova with relevant sociolinguistic comments on the documents forming its legal sphere, as well as taking into account the specifics of such regions as the unrecognized Transnistrian Moldovan Republic and the Autonomous Territorial Unit of Gagauz-Yeri. The article introduces the latest documents and materials on language policy of Moldova for the first time. The logic of the article structure enables to present the three key directions of language policy in the republic in a consistent and sufficiently detailed manner: language policy regarding the state language, with regard to the Romanian influence on it; policy regarding the Russian language as a popular means of inter- ethnic communication with a sufficient index of sustainability and its status; and policy regarding the languages of ethnic minorities that have long lived in the Moldovan region. The article gives a holistic view not only of the documents, but also of the motives, circumstances and processes of their adoption, as well as the consequences of each new step in the language policy promotion in the Republic of Moldova.

Use of nitrogen sufficiency index to estimate topdressing doses for common bean

ABSTRACT Portable chlorophyll meters can be used to improve the prediction of nitrogen (N) doses for common bean. This study aimed to evaluate two chlorophyll meters (Minolta SPAD-502 and ClorofiLOG CFL 1030) to predict topdressing N doses for the Pérola, TAA Gol and BRSMG Uai cultivars and for the VR 20 line. Eight field experiments (four genotypes and two devices) were carried out in a randomized blocks design, with four replicates, being the treatments topdressing N applications corresponding to four nitrogen sufficiency indices. There were discrepancies between the indices obtained by the different devices for the same genotype, as well as among those obtained with the same device for the different genotypes studied. Thus, when the index is used to define the N doses, the genotype and the chlorophyll meter used must be considered. In addition, the recommended index of 95 % should not be generalized to all the cultivars and should be reduced.

Remote Sensing Analysis of Agricultural Drone

Farmers have more requirements for the completion of cultivations. Remote sensing is a big technology for reducing this requirement. Now, we need an organic spraying system at a low cost. We have two methods, first one neural network algorithm of quantum geographic information system (QGIS) and another one global positioning system (GPS) with drone. This paper describes the analysis of drone remote sensing using the normalized difference vegetation index (NDVI)/Near-infrared band (NIR) sensor in a multispectral view of agricultural land. NIR and NDVI images had water content values and precision values which is mixed in managing water resources. NDVI sensors are loaded to produce high-density images. Real-time monitoring coupled in NIR imaging geometrically and radiometrically adjusted to measure temperature. Multispectral and hyperspectral views had used for analyzing the tested data. Standard irrigation level is 60% to produce the plant growing. Irrigation techniques followed the treatment of the plant within continuous data per second. The implemented view focused only on growth controlling of plant in-depth irrigation between 30 and 90 cm in 60% deviation. NDVI, green normalized difference vegetation index (GNDVI), soil brightness index (SBI), green vegetation index (GVI), degree of yellow vegetation index (YVI), nitrogen sufficiency index (NSI), perpendicular vegetation index (PVI), transformed vegetation index (TVI), soil adjusted vegetation index (SAVI) and vegetation condition index (VCI) vegetation indices are used to the correlation of plant growth control with managing leaf strength and import python packages display the Vegetation various Real-time value in QGIS. Correlation of plant growth p ≤0.01, r = 0.77 and − 0.77 with conductance. It measured degree and demonstrated GPS view using irrigation techniques to control water stress. It had used to estimate the leaf conductance rate with the variation of atmospherically changing. It can calculate real-time leaf stress analysis. This report provided a drone survey analysis of compost percentage and vegetation indices of agricultural land.

Comparison of Transparency and Shrinkage During Clearing of Insect Brains Using Media With Tunable Refractive Index.

Improvement of imaging quality has the potential to visualize previously unseen building blocks of the brain and is therefore one of the great challenges in neuroscience. Rapid development of new tissue clearing techniques in recent years have attempted to solve imaging compromises in thick brain samples, particularly for high resolution optical microscopy, where the clearing medium needs to match the high refractive index of the objective immersion medium. These problems are exacerbated in insect tissue, where numerous (initially air-filled) tracheal tubes branching throughout the brain increase the scattering of light. To date, surprisingly few studies have systematically quantified the benefits of such clearing methods using objective transparency and tissue shrinkage measurements. In this study we compare a traditional and widely used insect clearing medium, methyl salicylate combined with permanent mounting in Permount (“MS/P”) with several more recently applied clearing media that offer tunable refractive index (n): 2,2′-thiodiethanol (TDE), “SeeDB2” (in variants SeeDB2S and SeeDB2G matched to oil and glycerol immersion, n = 1.52 and 1.47, respectively) and Rapiclear (also with n = 1.52 and 1.47). We measured transparency and tissue shrinkage by comparing freshly dissected brains with cleared brains from dipteran flies, with or without addition of vacuum or ethanol pre-treatments (dehydration and rehydration) to evacuate air from the tracheal system. The results show that ethanol pre-treatment is very effective for improving transparency, regardless of the subsequent clearing medium, while vacuum treatment offers little measurable benefit. Ethanol pre-treated SeeDB2G and Rapiclear brains show much less shrinkage than using the traditional MS/P method. Furthermore, at lower refractive index, closer to that of glycerol immersion, these recently developed media offer outstanding transparency compared to TDE and MS/P. Rapiclear protocols were less laborious compared to SeeDB2, but both offer sufficient transparency and refractive index tunability to permit super-resolution imaging of local volumes in whole mount brains from large insects, and even light-sheet microscopy. Although long-term permanency of Rapiclear stored samples remains to be established, our samples still showed good preservation of fluorescence after storage for more than a year at room temperature.

Guiding fall fertilization of cool‐season turfgrass lawns with NDVI sufficiency index

AbstractFall N fertilizers are applied to turfgrass at predetermined rates instead of being based on plant‐N status. Normalized difference vegetative index (NDVI) and the sufficiency index (SI) concept are used to assess plant‐N status in some agronomic crops but has not been evaluated for turfgrass. This study was conducted across 3 yr in Connecticut to determine fall and spring NDVI SI values in a mixed species, cool‐season lawn. Field experiments were set out with varying fall N rates with NDVI measured weekly in October and November, and in late April. Quadratic and Linear‐Response and Plateau (LRP) models were significant (P < .0001) for all fall and spring SI values in response to fall N rates. Fall SI was maximized between 140 and 155 kg N ha−1 for the quadratic model and plateaued between 79 and 102 kg N ha−1 for the LRP model. Spring SI was maximized at 189 and plateaued at ≥116 kg N ha−1 for quadratic and LRP models, respectively. In relation to commonly recommended fall N rates of 24.5, 49, and 98 kg N ha−1, the models suggest that no supplemental N is needed when SI is ≥92, ≥95, and ≥99% of the N‐rich reference in the fall, respectively. Late April SI >89% of spring N‐rich reference would indicate that excess fertilizer was applied the previous fall at rates >49 kg N h−1. The NDVI SI can provide site‐specific fall N fertilization guidance of cool‐season turfgrass lawns.

Abstract 1771: Targeting oncogenic transcription in prostate cancer with a novel, oral bioavailable, and ultra-selective CDK9 inhibitor

Abstract Castration resistant prostate cancers (CRPCs) lose sensitivity to hormone therapy, but remain dependent on oncogenic transcription programs driven by the androgen receptor (AR) and other oncogenic transcription factors such as MYC. Using small molecule microarrays (SMMs), we screened HEK293 cellular lysates for compounds binding to exogenously expressed ARv7, a mutant splice form of AR that drives castration resistance. Although transcription factors like ARv7 and MYC are considered classically undruggable, SMMs are able to identify small molecule interactors of druggable co-factors and other proteins in complex with the target protein – in this case ARv7. SMM hits were triaged for the ability to selectively inhibit an AR dependent transcriptional reporter, and also for their ability to reduce proliferation in AR dependent tumor cells. From this screen, we identified KI-ARv3, a potent and selective inhibitor of CDK9. CDK9 is a cyclin-dependent kinase (CDK) that functions primarily as a general co-factor in RNA Polymerase II (RNA Pol II) transcription elongation. CDK9 is a well-characterized and important cofactor for AR, MYC, and other oncogenic transcription factors. In prostate cancer, CDK9 has been shown to modulate and be required for AR-specific gene expression. More broadly, transcriptional CDK inhibitors including those selective for CDK9 have shown strong potential as therapeutic agents owing to their ability to selectively downregulate oncogenic transcription programs and target tumors addicted to transcription factors such as AR or MYC. However, as CDK9 also plays a global role in transcription, it is unclear whether there exists a sufficient therapeutic index for clinical benefit. Prior clinical investigation of transcriptional CDK inhibitors has also been confounded by off-target interactions with other kinases and especially other CDKs that also play important roles in transcription and the cell cycle. We found that KI-ARv3 demonstrated excellent selectivity for CDK9 versus other CDKs and kinases, and further optimization of KI-ARv3 resulted in KB-00130742, an oral bioavailable CDK9 inhibitor with a biochemical IC50 of 15nM against CDK9 and greater than 50-fold selectivity for all profiled CDKs and greater than 100-fold selectivity against cell cycle CDKs. Both KI-ARv3 and KB-00130742 exhibited potent anti-tumor activity in CRPC models, as well as other models known to be dependent on MYC-driven transcription. In 22Rv1 CRPC cells, KB-00130742 rapidly downregulated nascent transcription, and preferentially depleted short half-life transcripts and AR driven oncogenic programs. In vivo, oral administration of KB-00130742 was well-tolerated and significantly reduced tumor growth in models of CRPC and leukemia. Overall these data support CDK9 inhibition using KB-00130742 as a therapeutic strategy to target AR dependence in CRPC and oncogenic transcription in other tumor types. Citation Format: André Richters, David Freeman, Christina Lee, Florian Kabinger, Shelby Doyle, Becky Leifer, Peter Mikochik, Sajjeev Jagannathan, Jost Vrabic Koren, Kristen Karlin, Calla M. Olson, Christopher Wilfong, Charles Y. Lin, Doug Saffran, Joseph Vacca, Norbert Bischofberger, Marius Pop, Angela N. Koehler. Targeting oncogenic transcription in prostate cancer with a novel, oral bioavailable, and ultra-selective CDK9 inhibitor [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 1771.

Analysis of the Imaging Characteristics of Holographic Waveguides Recorded in Photopolymers.

In this work, we study the imaging characteristics of an optical see-through display based on a holographic waveguide. To fabricate this device, two transmission holograms are recorded on a photopolymer material attached to a glass substrate. The role of the holograms is to couple the incident light between air and the glass substrate, accomplishing total internal reflection. The role of noise reflection gratings and shrinkage on the imaging characteristics of the device will be also explored. The holograms (slanted transmission gratings with a spatial frequency of 1690 lines/mm) were recorded on a polyvinyl alcohol acrylamide holographic polymer dispersed liquid crystal (HPDLC) material. We will show that sufficient refractive index modulation is achieved in the material, in order to obtain high diffraction efficiencies. We will demonstrate that the final device acts as an image formation system.

FINANCIAL SECURITY OF FARMS IN SELECTED European Union COUNTRIES IN THE CONTEXT OF ENVIRONMENTAL PROTECTION REQUIREMENTS

The article deals with the issue of financial security in an average farm in the Czech Republic, Poland, the Netherlands and Germany. The data collected under the FADN in the period 2013-2017 was used in this work. Financial security was measured using a cash adequacy indicator and the variability of family farm income is used. The work also used the subsidy rate, which determined how much farmers can feel safe in financial terms without any subsidies or financial support. Research shows that the worst situation from the perspective of the relationship between cash flows and debt servicing occurred on an average Dutch farm, and the highest sufficiency index was shown by a Polish farm. However, these discrepancies are the result of risk aversion in recent uncertain financial times. If additional requirements for outlays related to environmental protection appear, then the most difficult situation will occur on farms in the Czech Republic and Poland due to the fact that, for them, direct payments constitute a significant source of income. In these countries, a lack of compensation for any possible consequences arising from environmental restrictions may cause a feeling of financial insecurity.

Psychometric Validation of the Chinese Version of the Lymphedema Functioning, Disability, and Health Questionnaire for Upper Limb Lymphedema in Patients With Breast Cancer-Related Lymphedema.

Breast cancer-related lymphedema (BCRL) has a notable impact on patients' quality of life. However, no instrument is available to assess the problems in functioning due to BCRL in China. The aims of this study were to translate and validate a Chinese version of the Lymphedema Functioning, Disability, and Health Questionnaire for Upper Limb Lymphedema (Lymph-ICF-UL). A process of translation and cultural adaptation was conducted based on international standards. The study included 155 patients with BCRL and 90 patients without lymphedema. Psychometric properties that were tested consisted of internal consistency, test-rest reliability, content, construct and discriminant validity. The Cronbach's α was .92, and intraclass correlation coefficient was 0.83. Content validity was confirmed by a sufficient content validity index in item level and scale level. Exploratory factor analysis identified 5 factors accounting for 62.44% of the total variance, and confirmatory factor analysis fit indices were acceptable. Convergent validity was supported by a moderate correlation with the 36-item Short-Form Health Survey Questionnaire and relatively weak correlations with the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Core 30. There was good divergent validity with all hypotheses evaluating divergent validity were confirmed. Significant differences were found between the lymphedema and nonlymphedema groups. The Chinese version of the Lymph-ICF-UL is a valid and reliable instrument that can be used in both clinical and scientific settings in China. The Chinese version of the Lymph-ICF-UL could be applicable in assessing the impairments in function, activity limitations, and participation restrictions of Chinese patients with BCRL.

Where Does Nighttime Light Come From? Insights from Source Detection and Error Attribution

Nighttime light remote sensing has aroused great popularity because of its advantage in estimating socioeconomic indicators and quantifying human activities in response to the changing world. Despite many advances that have been made in method development and implementation of nighttime light remote sensing over the past decades, limited studies have dived into answering the question: Where does nighttime light come from? This hinders our capability of identifying specific sources of nighttime light in urbanized regions. Addressing this shortcoming, here we proposed a parcel-oriented temporal linear unmixing method (POTLUM) to identify specific nighttime light sources with the integration of land use data. Ratio of root mean square error was used as the measure to assess the unmixing accuracy, and parcel purity index and source sufficiency index were proposed to attribute unmixing errors. Using the Visible Infrared Imaging Radiometer Suite (VIIRS) nighttime light dataset from the Suomi National Polar-Orbiting Partnership (NPP) satellite and the newly released Essential Urban Land Use Categories in China (EULUC-China) product, we applied the proposed method and conducted experiments in two China cities with different sizes, Shanghai and Quzhou. Results of the POTLUM showed its relatively robust applicability of detecting specific nighttime light sources, achieving an rRMSE of 3.38% and 1.04% in Shanghai and Quzhou, respectively. The major unmixing errors resulted from using impure land parcels as endmembers (i.e., parcel purity index for Shanghai and Quzhou: 54.48%, 64.09%, respectively), but it also showed that predefined light sources are sufficient (i.e., source sufficiency index for Shanghai and Quzhou: 96.53%, 99.55%, respectively). The method presented in this study makes it possible to identify specific sources of nighttime light and is expected to enrich the estimation of structural socioeconomic indicators, as well as better support various applications in urban planning and management.

Spectral sensors prove beneficial in determining nitrogen fertilizer needs of <i>Urochloa brizantha</i> cv. Xaraés grass in Brazil

The objective of the present work was to evaluate the use of spectral sensors to determine nitrogen fertilizer requirements for pastures of Urochloa brizantha cv. Xaraés in Brazil. The experimental design was a randomized block design with 4 replications of 4 treatments: a control treatment (TT) without application of N; a reference treatment (TR) with N applied at a standard predetermined fixed rate (150 kg urea/ha/cycle); a treatment using GreenSeekerTM (TG) to determine N requirement by the canopy normalized difference vegetation index (NDVI); and a treatment using SPAD 502 (TS) to determine N requirement by foliar chlorophyll assessment. For treatments involving spectral sensors, N fertilizer was applied at half the rate of that in the reference treatment at the beginning of each cycle and further N was applied only when the nitrogen sufficiency index dropped below 0.85. The sensors used in the work indicated that no additional N fertilizer was required by these pastures above the half rates applied. Applying N at the reduced rates to the pastures was more efficient than the pre-determined fixed rate, as both sensor treatments and the fixed rate treatment produced similar total forage yields, with similar crude protein concentrations. All fertilized pastures supported similar stocking rates, while the sensor treatments used less N fertilizer, i.e. 75 kg urea/ha/cycle less than the reference plot. Longer-term studies to verify these findings are warranted followed by promotion of the technology to farmers to possibly reduce fertilizer application rates, improve profitability and provide environmental benefits.

Transforming Unmanned Aerial Vehicle (UAV) and Multispectral Sensor into a Practical Decision Support System for Precision Nitrogen Management in Corn

Determining the optimal nitrogen (N) rate in corn remains a critical issue, mainly due to unaccounted spatial (e.g., soil properties) and temporal (e.g., weather) variability. Unmanned aerial vehicles (UAVs) equipped with multispectral sensors may provide opportunities to improve N management by the timely informing of spatially variable, in-season N applications. Here, we developed a practical decision support system (DSS) to translate spatial field characteristics and normalized difference red edge (NDRE) values into an in-season N application recommendation. On-farm strip-trials were established at three sites over two years to compare farmer’s traditional N management to a split-application N management guided by our UAV sensor-based DSS. The proposed systems increased nitrogen use efficiency 18.3 ± 6.1 kg grain kg N−1 by reducing N rates by 31 ± 6.3 kg N ha−1 with no yield differences compared to the farmers’ traditional management. We identify five avenues for further improvement of the proposed DSS: definition of the initial base N rate, estimation of inputs for sensor algorithms, management zone delineation, high-resolution image normalization approach, and the threshold for triggering N application. Two virtual reference (VR) methods were compared with the high N (HN) reference strip method for normalizing high-resolution sensor data. The VR methods resulted in significantly lower sufficiency index values than those generated by the HN reference, resulting in N fertilization recommendations that were 31.4 ± 10.3 kg ha−1 higher than the HN reference N fertilization recommendation. The use of small HN reference blocks in contrasting management zones may be more appropriate to translate field-scale, high-resolution imagery into in-season N recommendations. In view of a growing interest in using UAVs in commercial fields and the need to improve crop NUE, further work is needed to refine approaches for translating imagery into in-season N recommendations.

METHODOLOGY FOR MODELING MACROECONOMIC LIMITATIONS OF SCIENTIFIC AND TECHNOLOGICAL PROGRESS

The subject of this article is the methodology of macroeconomic modeling of scientific and technological progress from the point of view, which is an alternative to the modern paradigm of unlimited potential for economic efficiency.The research is based on the general scientific method of transition from simple to complex. As a starting point, the general laws of scientific and technical progress are selected, independent of individual economic factors. The analysis of long-term economic dynamics is based on the model of limited scientific and technological progress (LSTP-model), first proposed in this article. During the simulation, it is shown that even with infinite resources directed to the R&D sector, the rate of STP has its limit. In this connection, the conclusion is formulated that not only the volume and quality of resources in the R&D sector, but also the duration of their use are important for technological development.The methodology used in the article implements the general scientific principle of correspondence. It is shown that: 1) the classical models of unlimited STP are the limiting case of one of the proposed equations; 2) traditional production functions proved to be the limiting case of the proposed production function with restrictions on maximum product efficiency and minimum efficiency of production factors.A feature of the study is a multivariate approach - consideration and comparative analysis of possible macroeconomic functions and equations of dynamics. Based on this approach, functions and equations were determined that describe the unevenness of economic development, fluctuations in the rate of growth of efficiency, and endogenous waves of STP. It is shown that the new indicators (the potential for increasing efficiency, the sufficiency index of the STP factor) and the functions made up of them allow us to adequately analyze the increasingly complex aspects of scientific and technological progress. A function of exogenous dynamics reflecting the exogenous effect on STP is proposed. An analysis of this function made it possible to adequately describe the historical dynamics of various economic systems that differ in the balance of positive and negative exogenous factors.The general laws of STP are modeled using complex (including implicit) functions. Depending on the specifics of the process under study, complex functions of higher orders can be applied. From a mathematical point of view, the presented equations of dynamics are classified as ordinary autonomous first-order differential equations. Such a mathematical apparatus made it possible to demonstrate the need to observe the general scientific principle of the homogeneity of time. It is shown that limited scientific and technological progress can be described using the utility function.