Experimental study of the distribution of the heights of sugar beet root crowns above the soil surface

ArticleThe results of experimental studies and operational tests of the sugar beet harvesting process carried out recently reveal that the latest models of beet harvesters produced in Europe and America cause considerable loss of the sugar-bearing mass. The source of this loss is mainly the poor topping of the crowns of standing sugar beet roots, more specifically the excessively low point at which the tops are cut off, which results in the straight out loss of sugar-bearing mass. Thus, there is need to search for such engineering solutions that would avoid both the loss of sugar-bearing mass and the presence of residual haulm on the roots. The aim of this study was to reduce the loss of sugar-bearing mass in the process of topping sugar beet root crowns. The results of this research into the distribution of the heights that root crowns protrude above the soil surface have confirmed the hypothesis that it follows the normal distribution. Based on the results, it has been established that this distribution has the following statistical parameters: mean deviation a = 20–30 mm, mathematical expectation m = 40...60 mm. The laboratory unit developed for this work and the field studies performed with it have provided sufficient evidence to develop a new system to automatically adjust the topping height on state-of-the-art root crop harvesters

Comparison of essential oil content of Matricaria recutita L. from different origins

En el presente trabajo se han determinado las variaciones en la composición de aceites esenciales de Chamomilla recutita (L.) Rauschert, especie cultivada en distintos países de Europa. Los aceites esenciales han sido extraídos de las muestras secas, con unos rendimientos de 3.6–6.6 mg/g y en ellos se han identificado 38 componentes, los cuales representan más del 95% del total del aceite esencial. El principal compuesto biológicamente activo en el aceite esencial de la manzanilla procedente de Gran Bretaña fue el óxido de β-bisabolol (25%); en los procedentes de Bélgica, Estonia y Francia predominaba el óxido de α-bisabolol (43–55%) y el compuesto principal en el de Hungría fue el α-bisabolol (24%). El (E)-β-farneseno se encontraba en sus mayores proporciones (5-7%) en los de Bélgica y Francia, mientras que el camazuleno representaba del 1 al 14% del total de los distintos aceites esenciales siendo más abundante en los aceites procedentes de Gran Bretaña (14%).Variations in the essential oil content of Matricaria recutita L., cultivated in different European countries, were determined. The oil was obtained in yields of 3.6-6.6 mg/g from dried samples. 38 components were identified, representing over 95% of the total yield of oil. The principal biologically active compound in chamomile oil, of British origin, was bisabolol oxide B (25%). In oils from Belgium, Estonia and France, bisabolol oxide A (43-55%) was predominant, whereas in Hungarian oil the main compound was alpha-bisabolol (24%). (E)-beta-Farnesene content was predominant (5–7%) in oils from Belgium and France. Chamazulene was present in 1–14% of oils and its content was highest in oil of British origin (14%).Este trabajo ha sido financiado a través de la beca número 4332 de la Fudación Científica de Estonia

Comparación de aceites esenciales de Matricaria recutita L. de origen diverso

Variations in the essential oil content of Matricaria recutita L., cultivated in different European countries, were determined.The oil was obtained in yields of 3.6-6.6 mg/g from dried samples. 38 components were identified, representing over 95%of the total yield of oil. The principal biologically active compound in chamomile oil, of British origin, was bisabololoxide B (25%). In oils from Belgium, Estonia and France, bisabolol oxide A (43-55%) was predominant, whereas inHungarian oil the main compound was alpha-bisabolol (24%). (E)-beta-Farnesene content was predominant (5–7%) inoils from Belgium and France. Chamazulene was present in 1–14% of oils and its content was highest in oil of Britishorigin (14%).En el presente trabajo se han determinado las variaciones en la composición de aceites esenciales de Chamomillarecutita (L.) Rauschert, especie cultivada en distintos países de Europa. Los aceites esenciales han sido extraídos delas muestras secas, con unos rendimientos de 3.6–6.6 mg/g y en ellos se han identificado 38 componentes, los cualesrepresentan más del 95% del total del aceite esencial. El principal compuesto biológicamente activo en el aceiteesencial de la manzanilla procedente de Gran Bretaña fue el óxido de β-bisabolol (25%); en los procedentes deBélgica, Estonia y Francia predominaba el óxido de α-bisabolol (43–55%) y el compuesto principal en el de Hungríafue el α-bisabolol (24%). El (E)-β-farneseno se encontraba en sus mayores proporciones (5-7%) en los de Bélgica yFrancia, mientras que el camazuleno representaba del 1 al 14% del total de los distintos aceites esenciales siendo másabundante en los aceites procedentes de Gran Bretaña (14%)

The theory of vibrational wave movement in drying grain mixture

This paper outlines a theory that involves the vibrational wave transportation of bulk grain during the course of passing that grain under an infrared radiation source, in a working thermal radiation drying chamber, and using a vibrational wave transporter belt that has been developed by the authors of this paper. The main outstanding feature of the proposed design is the presence of mechanical off-centre vibration drives which generate the vibration in the working rollers at a preset amplitude and frequency, thereby generating a mechanical wave on the surface of the flexible transporter belt which ensures the movement of bulk grain along the processing zone which itself is being subjected to infrared radiation. A calculation method was developed for the oscillation system that is used in conjunction with the vibrational transportation of the grain mass, in order to be able to determine the forces that may be present in the vibrational system and to prepare the differential calculations for the movement of the vibrational drive’s actuators, utilising for this purpose Type II Lagrange equations. The solving of the aforementioned integral equations on a PC yielded a number of graphical dependencies in terms of kinetic and dynamic parameters for the vibrational system described above; the analysis of those dependencies provided a rational structural, along with kinetic and dynamic indicators. According to the results that were taken from theoretical and experimental studies on the functioning of the developed infrared grain dryer combined with a vibrational exciter, stable movement for its working roller takes place if the angular velocity of a drive shaft is changed within the range of between 50–80 rads-1, whereas the amplitude of the indicated oscillations falls within the range of 3.0–4.0 mm. It has been discovered that a rational speed when transporting soy seeds during infrared drying falls between the range of between 0.15–0.60 cm·s-1, whereas the amplitude of the indicated oscillations falls within the range of 3.0–4.0 mm. An increase of this parameter within the stated limits increases the time that it takes to achieve the stage in which a constant drying soy speed is reached by more than 2.5 times (from 205 seconds to 520 seconds), stabilising the figure at a level of 520 seconds, which makes it possible to recommend a range of transport speeds of between 0.15–0.40 cm·s-1 under infrared radiation for the seeds in order to achieve the required moisture content with a single pass of the produce on the wave transporter. With that in mind, the power consumption levels for the vibrational exciter do not exceed 50W, while the angular velocity of the drive shaft’s rotation falls within the range of between 100– 120 rads-1 . The results of the experimental study that has been conducted indicated that a rational transportation speed for the soy seeds on the wave transporter under infrared radiation is between 0.15–0.40 cm·s-1

A mathematical model of the rear-trailed top harvester and an evaluation of its motion stability

Received: October 7th, 2021 ; Accepted: December 10th, 2021 ; Published: December 10th, 2021 ; Correspondence: [email protected] the quality of sugar beet harvesting to a great extent depends on the first operation in the process, which involves cutting and harvesting sugar beet tops. This technological process is performed with the use of either the haulm harvesting modules of beet harvesters or top harvesting machines as separate agricultural implements, which are aggregated with a tractor. At the same time, front-mounted harvesters are as widely used as trailed asymmetric implements, in which case the aggregating tractor moves on the already harvested area of the field. The purpose of this work is to determine the optimal design and kinematic parameters that would improve the stability in the performance of the technological process of harvesting sugar beet tops by means of developing the basic theory of the plane-parallel motion performed by the rear-trailed asymmetric top harvester. As a result of the analytical study, an equivalent scheme has been composed, on the basis of which a new computational mathematical model has been developed for the plane-parallel motion of the asymmetric top harvester in the horizontal plane on the assumption that the connection between the wheeled tractor and the rear-trailed top harvester is made in the form of a cylindrical hinge joint. Using the results of mathematical modelling, the system of linear second-order differential equations that determines the transverse movement of the centre of mass of the aggregating wheeled tractor and the rotation of its longitudinal symmetry axis by a certain angle about the said centre of mass as well as the angle of deviation of the rear-trailed asymmetric top harvester from the longitudinal symmetry axis of the tractor at an arbitrary instant of time has been obtained. The solving of the obtained system of differential equations provides for determining the stability and controllability of the motion performed by the asymmetric machine-tractor unit, when it performs the technological process of harvesting sugar beet tops

A Three-Parameter Binomial Approximation

We approximate the distribution of the sum of independent but not necessarily identically distributed Bernoulli random variables using a shifted binomial distribution where the three parameters (the number of trials, the probability of success, and the shift amount) are chosen to match up the first three moments of the two distributions. We give a bound on the approximation error in terms of the total variation metric using Stein's method. A numerical study is discussed that shows shifted binomial approximations typically are more accurate than Poisson or standard binomial approximations. The application of the approximation to solving a problem arising in Bayesian hierarchical modeling is also discussed

Climate and mating systems as drivers of global diversity of parental care in frogs

Aim Amphibians exhibit unusually diverse reproductive modes, including a wide array of parental care strategies. The evolutionary drivers of this diversity, however, remain unclear. Here, we investigate three major factors that might predict interspecific variation in parental care strategies: climate, intrasexual selection and social environment. We hypothesize that some forms of care evolved to cope with harsh conditions, such as dry or unpredictable habitats. We contrast this prediction with the hypothesis that parental roles have co‐evolved with the social environment and mating systems. Location Global. Major taxa studied Frogs and toads (Amphibia: Anura). Time period Extant taxa that represent c . 220 Myr of evolutionary history. Methods Using geographical and behavioural data for 971 species of frogs and toads that represent 45 anuran families, we quantified the global distribution of four forms of parenting separately for males and females: nest building, nest and/or tadpole attendance, carrying and nourishment. We used phylogenetic comparative analyses to investigate whether climate, social environment and mating systems predicted interspecific variation in parental care. Results Our results showed that climatic effects contribute to parental care diversity: in cool and humid climates the males provide offspring attendance, whereas in predictable temperatures endotrophy occurs, whereby the female provides all nutrients for the offspring until metamorphosis. In addition, we found other associations between mating systems and forms of parental care: uniparental clutch attendance by males is present in species with territorial defence, whereas cooperative nest building co‐occurs with sperm competition. The type of parental care is not associated with adult sex ratios. Main conclusions No specific form of care is associated with hostile environments; in fact, some forms of care occur in beneficial conditions, whereas others are used independently from the climate. Instead, parenting diversity has co‐evolved closely with mating systems in frogs

Spatial distribution and male mating success of Anopheles gambiae swarms

<p>Abstract</p> <p>Background</p> <p><it>Anopheles gambiae </it>mates in flight at particular mating sites over specific landmarks known as swarm markers. The swarms are composed of males; females typically approach a swarm, and leave <it>in copula</it>. This mating aggregation looks like a lek, but appears to lack the component of female choice. To investigate the possible mechanisms promoting the evolution of swarming in this mosquito species, we looked at the variation in mating success between swarms and discussed the factors that structure it in light of the three major lekking models, known as the female preference model, the hotspot model, and the hotshot model.</p> <p>Results</p> <p>We found substantial variation in swarm size and in mating success between swarms. A strong correlation between swarm size and mating success was observed, and consistent with the hotspot model of lek formation, the <it>per capita </it>mating success of individual males did not increase with swarm size. For the spatial distribution of swarms, our results revealed that some display sites were more attractive to both males and females and that females were more attracted to large swarms. While the swarm markers we recognize help us in localizing swarms, they did not account for the variation in swarm size or in the swarm mating success, suggesting that mosquitoes probably are attracted to these markers, but also perceive and respond to other aspects of the swarming site.</p> <p>Conclusions</p> <p>Characterizing the mating system of a species helps understand how this species has evolved and how selective pressures operate on male and female traits. The current study looked at male mating success of <it>An. gambiae </it>and discussed possible factors that account for its variation. We found that swarms of <it>An. gambiae </it>conform to the hotspot model of lek formation. But because swarms may lack the female choice component, we propose that the <it>An. gambiae </it>mating system is a lek-like system that incorporates characteristics pertaining to other mating systems such as scramble mating competition.</p

Male Responses to Conspecific Advertisement Signals in the Field Cricket Gryllus rubens (Orthoptera: Gryllidae)

In many species males aggregate and produce long-range advertisement signals to attract conspecific females. The majority of the receivers of these signals are probably other males most of the time, and male responses to competitors' signals can structure the spatial and temporal organization of the breeding aggregation and affect male mating tactics. I quantified male responses to a conspecific advertisement stimulus repeatedly over three age classes in Gryllus rubens (Orthoptera: Gryllidae) in order to estimate the type and frequency of male responses to the broadcast stimulus and to determine the factors affecting them. Factors tested included body size, wing dimorphism, age, and intensity of the broadcast stimulus. Overall, males employed acoustic response more often than positive phonotactic response. As males aged, the frequency of positive phonotactic response decreased but that of the acoustic response increased. That is, males may use positive phonotaxis in the early stages of their adult lives, possibly to find suitable calling sites or parasitize calling males, and then later in life switch to acoustic responses in response to conspecific advertisement signals. Males with smaller body size more frequently exhibited acoustic responses. This study suggests that individual variation, more than any factors measured, is critical for age-dependent male responses to conspecific advertisement signals