Predviđanje kotrljanja čestice đubriva duž lopatice centrifugalnog rasipača sa diskom

The paper analyzes the motion of idealized spherical homogeneous fertilizer particle along the straight vane attached to flat rotating disc. The analysis, based on the assumption on the pure rolling of the particle along the vane (without sliding), has been performed in the non-inertial reference coordinate system, which rotates together with the spreader disk. The particle motion along the vane is described by hyperbolic cosine function, which is the solution of the ordinary in-homogenous secondorder differential equation having constant coefficients. Solution of this kind represents an approximation of the real motion of fertilizer particle along the radial vane fixed to horizontal disc rotating at constant angular velocity. However, it can be very useful for optimization of centrifugal spreader design and working parameters, as well as for further analysis of the whole fertilizer spreading process that also includes particle flight.U radu je analizirano kretanje idealizovane, loptaste, homogene čestice mineralnog đubriva duž radijalne lopatice postavljene na rotirajućem disku centrifugalnog rasipača đubriva. Analiza, zasnovana na pretpostavci o kotrljanju čestice duž lopatice bez klizanja, izvedena je u neinercijalnom referentnom koordinatnom sistemu koji rotira zajedno sa diskom za rasipanje đubriva. Kretanje čestice duž lopatice je opisano hiperboličnom kosinusnom funkcijom, koja predstavlja rešenje obične homogene diferencijalne jednačine drugog reda sa konstantnim koeficijentima, koja opisuje dinamiku čestice. Rešenje ove vrste predstavlja aproksimaciju stvarnog kretanja čestice đubriva duž lopatice diska koji rotira konstantnom ugaonom brzinom. Međutim, može biti veoma korisno za optimizaciju dizajna centrifugalnog raspršivača i njegovih radnih parametara, kao i za dalju analizu čitavog procesa rasipanja đubriva koji obuhvata i let čestice u vazduhu po napuštanju lopatice

Colored Tverberg Theorems for non-prime powers

We prove a relative of the Optimal (Type B)} Colored Tverberg theorem of \v{Z}ivaljevi\'{c} and Vre\'{c}ica which modifies this results in two different ways. (1) Our result is valid if the number of rainbow faces is $q= p^n-1$, where $p$ is a prime. (2) The size of rainbow simplices satisfies the condition $\vert C_i\vert \in \{2q-2, 2q+1\}$ while in the original theorem $\vert C_i\vert = 2q-1$ for all $i$.Comment: arXiv admin note: text overlap with arXiv:2210.09101, arXiv:2210.0780

The influence of tillage system on the wheat sowing quality

In agricultural production, sowing is one of the most important agro-technical operations that influence the quality of the product and yield. The crops sowing quality, including wheat, depends on properly prepared soil, that is, on the quality of soil cultivation. However, despite well-executed soil cultivation, satisfactory results cannot always be achieved if sowing is not done in an appropriate manner. The achieved depth of sowing affects the speed of sprouting, rooting, resistance of plants to low temperature and drought, intensity of budding, growth and development, and achieving the highest yield in certain conditions. In unfavorable agro-technical conditions, and especially in the conditions of dry farming, optimal conditions for high-quality sowing often cannot be ensured by applying the conventional method. Therefore, new cultivation and sowing systems are being applied in order to perform high-quality sowing in time. During the experiment, the influences of the tillage system and sowing method on the sowing depth and the depth of the formation of the tillering nodes were registered. The results of two-year study are given, where four methods of tillage were applied, namely conventional tillage at depths of up to 25 cm and three reduced tillage methods at different depths. Reduced cultivation with a discc harrrow was done at a depths between 8 and 12 cm, and reduced cultivation with rototiller was done at depths of 5-10 cm and 10-15 cm. During the tests, the sowing depth and the depths of the tillering nodes were determined by direct measuring of the knots positions of the analyzed plants. Furthermore, it was verified that depth of the knot has a significant effect on the resistance of wheat to low temperatures during winter and lack of moisture during summer droughts. Achieved results enable further optimization of applied cultivation and sowing systems

Efficiency of alfalfa hay mowing machines under the dryland conditions

This paper presents the tests results of three types of hay mowing machines (later in text: mowers), namely a self-propelled oscillatory mower-conditioner and two tractor-mounted mowers with oscillatory and rotary blades, used to mow alfalfa grown under dry land conditions in the region of central Serbia during three seasons in 2014, 2015 and 2016. Although characterized by older design, they are still commonly used at smaller and medium size farms in this region. Therefore, their optimal exploitation parameters are still of large importance for hay quality and production efficiency and sustainability. The exploitation parameters of all three mowers generally increased linearly with higher speeds, having high R2 values (over 0,8), with rare exceptions. The regression coefficients b clearly showed that the self-propelled mower-conditioner achieved maximum increase in production performance (b = 0,3606), compared with the oscillatory (b = 0,1158) and rotary mowers (b = 0,1414). Mower design had a significant (p ≤ 0,001) effect on cutting and chopping losses, production performance, and specific fuel consumption (p ≤ 0,05). The tests confirmed the superiority of the self-propelled mower over the two mowers aggregated with tractors

Seasons and planting densities interaction on forage production of eight hybrids maize, Ecuador

ABSTRACT Objective. To assess the interaction effect of the season and planting densities on the production of eight INIAP corn hybrids. Materials and methods. A research process was conducted in 2013. It was applied a split - split plot design with three replication and Tukey test was used. It was evaluated two planting seasons (28 January and 8 April), they were placed in large plots. Two planting densities (65,500 y 125,000 plants/ha), that were located in the subplots and eight INIAP corn hybrids arranged in the sub- subplots. The evaluated variables were Fresh Matter, Dry Matter, Plant Height and Crude Protein Results. Fresh Matter and Crude Protein productions were influenced by planting seasons. Plant densities affected the production of Fresh Matter, Dry Matter and Plant Height, as well as the interaction season by corn INIAP hybrids. While INIAP corn hybrids showed statistical differences in the production of Fresh, Dry Matter, Plant Height and Crude Protein. The eight INIAP hybrids productions were: Fresh Matter (58.86 ton/ha ±5.19); Dry Matter (21.45 ton/ha ±4.71); Plant Height (2.46 m ±0.16) and Crude Protein (10.6±1.12). Conclusions. The performance showed by hybrids INIAP CML-172, INIAP 6021 and INIAP 551 were very acceptable forage material and could be used for silage purposes. RESUMEN Objetivo. Evaluar el efecto de la interacción época y densidad de siembra en ocho híbridos de maíz para producción de forraje sobre la obtención de materia fresca MF, seca MS, altura de planta AP y proteína cruda PC. Materiales y métodos. Se empleó un diseño de parcela dos veces dividida con tres repeticiones. Se evaluó el efecto de dos épocas de siembra (28 de enero y el 8 de abril) que se dispusieron en la parcelas grandes, dos densidades de siembra (65.500 y 125.000 plantas/ha) que se ubicaron en las subparcelas y ocho híbridos de maíz INIAP dispuestas en las sub-subparcelas. Las variables evaluadas fueron producción de MF, MS, AP y PC. Resultados. La época de siembra tuvo su influencia sobre la producción de MF y contenido de PC. La densidad de cultivo y época de siembra afectó la producción de MF, MS y AP por híbridos de maíz. Mientras que los híbridos INIAP de maíz mostraron diferencias estadísticas (p<0.001) en la producción de MF, MS, AP y PC. La producción de los ocho híbridos INIAP fue de MF (58.86 Ton/ha ±5.19); MS (21.45 Ton/ha ±4.71); AP (2.46 m±0.16) y PC (10.6±1.12). Conclusiones. Los rendimientos mostrados por los híbridos INIAP CML 172, INIAP 6021 e INIAP 551 son materiales aceptables con relación a las variables evaluadas y pueden ser empleados especialmente para ensilaje

Mathematical Method for Droplet Size Distribution of Agricultural Nozzles

One of the technical factors from agricultural nozzles and overall plant protection is droplet diameter, which exclusively depends on working pressure, ISO number and nozzle type. Therefore, this paper was aimed to describe mathematical model for droplet size distribution. Through field exploitation experiment, data was used from three ISO numbers of nozzles (hollow cone 80 015; 02 and 03), two air-assisted sprayers (axial and radial fan) and two permanent crops (vineyard and an apple orchard). Water sensitive papers were used for evaluation of droplet diameters, and digital image analysis with Image J software was used for data processing. Mathematical model through homogenous diffusion equation and simplified differential equation shows that droplet size distribution had exponential function of modelling. Theoretical mathematical model was confirmed in experimental results, where coefficient of determination of exponential regression model for 80 015 nozzles was 0.93 with 5.15 of RMSE. The same coefficient for 80 02 nozzles was 0.96 with 2.88 of RMSE and for 80 03 nozzle R2 was 0.93 with 3.25 of RMSE. In addition, it is proved that droplet diameter depends on operating pressure with very high negative correlation (80 03 nozzles: r = −0.98; 80 02 nozzles: r = −0.97; 80 015 nozzles: r = −0.95). This data will help future researchers in their papers to facilitate and describe similar models for plat protection processes, and all agricultural producers to determine optimal operating pressure which is immensely important in economic, biologic, technical and ecologic aspect

A randomized, double-blind, placebo-controlled trial of Ad5FGF-4 gene therapy and its effect on myocardial perfusion in patients with stable angina

AbstractObjectivesThe primary objective of this study was to determine whether intracoronary administration of the adenoviral gene for fibroblast growth factor (Ad5FGF-4) can improve myocardial perfusion compared with placebo.BackgroundAnimal studies and observational clinical studies have shown improvement in perfusion of the ischemic myocardium using genes encoding angiogenic growth factors; however, randomized, double-blind data in humans are lacking.MethodsWe performed a randomized, double-blind, placebo-controlled trial of intracoronary injection of 1010adenoviral particles containing a gene encoding fibroblast growth factor (Ad5FGF-4) to determine the effect on myocardial perfusion. Fifty-two patients with stable angina and reversible ischemia comprising >9% of the left ventricle on adenosine single-photon emission computed tomography (SPECT) imaging were randomized to gene therapy (n = 35) or placebo (n = 17). Clinical follow-up was performed, and 51 (98%) patients underwent a second adenosine SPECT scan after 8 weeks.ResultsOverall (n = 52), the mean total perfusion defect size at baseline was 32.4% of the left ventricle, with 20% reversible ischemia and 12.5% scar. At eight weeks, Ad5FGF-4 injection resulted in a significant reduction of ischemic defect size (4.2% absolute, 21% relative; p < 0.001) and placebo-treated patients had no improvement (p = 0.32). Although the change in reversible perfusion defect size between Ad5FGF-4 and placebo was not significant (4.2% vs. 1.6%, p = 0.14), when a single outlier was excluded a significant difference was observed (4.2% vs. 0.8%, p < 0.05). Ad5FGF-4 was well tolerated and did not result in any permanent adverse sequelae.ConclusionsIntracoronary injection of Ad5FGF-4 showed an encouraging trend for improved myocardial perfusion; however, further studies of therapeutic angiogenesis with Ad5FGF-4 will be necessary

Inhibition of transforming growth factor-β restores endothelial thromboresistance in vein grafts

BackgroundThrombosis is a major cause of the early failure of vein grafts (VGs) implanted during peripheral and coronary arterial bypass surgeries. Endothelial expression of thrombomodulin (TM), a key constituent of the protein C anticoagulant pathway, is markedly suppressed in VGs after implantation and contributes to local thrombus formation. While stretch-induced paracrine release of transforming growth factor-β (TGF-β) is known to negatively regulate TM expression in heart tissue, its role in regulating TM expression in VGs remains unknown.MethodsChanges in relative mRNA expression of major TGF-β isoforms were measured by quantitative polymerase chain reaction (qPCR) in cultured human saphenous vein smooth muscle cells (HSVSMCs) subjected to cyclic stretch. To determine the effects of paracrine release of TGF-β on endothelial TM mRNA expression, human saphenous vein endothelial cells (HSVECs) were co-cultured with stretched HSVSMCs in the presence of 1D11, a pan-neutralizing TGF-β antibody, or 13C4, an isotype-control antibody. Groups of rabbits were then administered 1D11 or 13C4 and underwent interpositional grafting of jugular vein segments into the carotid circulation. The effect of TGF-β inhibition on TM gene expression was measured by qPCR; protein C activating capacity and local thrombus formation were measured by in situ chromogenic substrate assays; and VG remodeling was assessed by digital morphometry.ResultsCyclic stretch induced TGF-β1 expression in HSVSMCs by 1.9 ± 0.2-fold (P < .001) without significant change in the expressions of TGF-β2 and TGF-β3. Paracrine release of TGF-β1 by stretched HSVSMCs inhibited TM expression in stationary HSVECs placed in co-culture by 57 ± 12% (P = .03), an effect that was abolished in the presence of 1D11. Similarly, TGF-β1 was the predominant isoform induced in rabbit VGs 7 days after implantation (3.5 ± 0.4-fold induction; P < .001). TGF-β1 protein expression localized predominantly to the developing neointima and coincided with marked suppression of endothelial TM expression (16% ± 2% of vein controls; P < .03), a reduction in situ activated protein C (APC)-generating capacity (53% ± 9% of vein controls; P = .001) and increased local thrombus formation (3.7 ± 0.8-fold increase over vein controls; P < .01). External stenting of VGs to limit vessel distension significantly reduced TGF-β1 induction and TM downregulation. Systemic administration of 1D11 also effectively prevented TM downregulation, preserved APC-generating capacity, and reduced local thrombus in rabbit VGs without observable effect on neointima formation and other morphometric parameters 6 weeks after implantation.ConclusionTM downregulation in VGs is mediated by paracrine release of TGF-β1 caused by pressure-induced vessel stretch. Systemic administration of an anti-TGF-β antibody effectively prevented TM downregulation and preserved local thromboresistance without negative effect on VG remodeling.Clinical RelevanceVein grafts (VGs) are commonly used conduits for coronary and peripheral arterial bypass surgeries. Thrombosis is a major cause of early VG failure. Trombomodulin (TM), a key component of the anticoagulant protein C pathway, is downregulated early after VG implantation and facilitates local thrombus formation. We found that paracrine release of transforming growth factor-β1 (TGF-β1), caused by pressure-induced stretch, was a potent negative regulator of TM in rabbit VGs. Administration of a neutralizing anti-TGF-β antibody effectively prevented TM downregulation and reduced local thrombus generation without adversely affecting long-term VG remodeling. This may represent a novel strategy to improve patency in patients undergoing arterial bypass procedures

Performance analysis of MIMO-SESS with Alamouti scheme over Rayleigh fading channels

Las unidades fraseológicas han estado presentes en los repertorios desde los comienzos de la lexicografía. Y no solamente en los diccionarios generales, sino también en las catalogaciones especializadas, tanto de naturaleza monolingüe como bilingüe. No obstante, siempre ha existido dificultad terminológica para la categorización de los diferentes fenómenos del discurso repetido. Si bien esto no ha sido un inconveniente para que se hayan publicado numerosas compilaciones, sobre todo de refranes en un principio, ya que en la actualidad, fundamentalmente, gracias al auge de los estudios teóricos sobre fraseología, han proliferado otras obras (algunas aplicadas a la glosodidáctica, dada su importancia hoy en día) en las que se da cabida con mayor frecuencia a enunciados de valor específico y a locuciones; en unas ocasiones, ahondando en el origen que les dio entidad y, en otras, estableciendo etiquetados precisos que hasta el momento solían estar ausentes, pero con la finalidad, al fin y al cabo, de desentrañar el sentido, dada la escasa deducibilidad que presentan estas secuencias fijadas por la simple suma de sus elementos constitutivos. Un análisis de estos repertorios a través de los siglos, es, por tanto, el objetivo de este trabajo.Since the beginning of lexicography, phraseological units have been included in repertoires; not only in general dictionaries, but also in monolingual and bilingual specialized catalogues. However, there have always been terminological difficulties for classifying various phenomena of repeated speech. Although this has not been inconvenient for publishing many compilations of sayings, especially at the beginning, because nowadays they frequently include utterances with precise value and idioms, mainly due to the rise of theoretical studies on phraseology (some applied to ASL Linguistics, given its importance today). In them, sometimes, the origin of the phraseological unit is included and, in others, accurate labels that were absent before are determined in order, finally and ultimately, to unravel the meaning, given the reduced deductibility that these sequences present from the simple sum of their constituent elements. The objective of this work is, therefore, an analysis of these repertories throughout the centuries