This work presents quantitative prediction of severity of the disease caused by Phytophthora infestans in potato crops using machine learning algorithms such as multilayer perceptron, deep learning ...convolutional neural networks, support vector regression, and random forests. The machine learning algorithms are trained using datasets extracted from multispectral data captured at the canopy level with an unmanned aerial vehicle, carrying an inexpensive digital camera. The results indicate that deep learning convolutional neural networks, random forests and multilayer perceptron using band differences can predict the level of Phytophthora infestans affectation on potato crops with acceptable accuracy.
Brassinosteroids (BRs) are an important group of polyhydroxylated naturally occurring steroidal phytohormones found in the plant kingdom in extremely low amounts. Due to the low concentrations in ...which these compounds are found, much effort has been dedicated to synthesizing these compounds or their structural analogs using natural and abundant sterols. In this work, we report the synthesis of new brassinosteroid analogs obtained from hyodeoxycholic acid, with a 3,6 dioxo function, 24-Nor-22(S)-hydroxy side chain and p-substituted benzoate function at C-23. The plant growth activities of these compounds were evaluated by two different bioassays: rice lamina inclination test (RLIT) and BSI. The results show that BRs’ analog with p-Br (compound 41f) in the aromatic ring was the most active at 1 × 10−8 M in the RLIT and BSI assays. These results are discussed in terms of the chemical structure and nature of benzoate substituents at the para position. Electron-withdrawing and size effects seems to be the most important factor in determining activities in the RLIT assay. These results could be useful to propose a new structural requirement for bioactivity in brassinosteroid analogs.
The synthesis and biological evaluation of brassinosteroids (BRs) analogs with chemical modification in the side alkyl chain is a matter of current interest. Recently, a series of BR analogs with ...phenyl or benzoate groups in the alkyl chain have been reported. The effect of substitution in the aromatic ring on the biological activities of these new analogs has been evaluated, and the results suggest that the bioactivity is enhanced by substitution with an F atom. In this context, we have synthesized, characterized, and evaluated a series of new analogs of 23,24-bisnorcholenic type in which the benzoate group at the C-22 position is substituted with an F atom at "
or
" positions. Plant growth-promoting activities were evaluated by using the rice lamina inclination test and bean second internode biotest. The results obtained with both bioassays indicate that the compound with an F atom in the para position on the aromatic ring is the most active BR analog and in some cases is even more active than brassinolide. The docking study confirmed that compounds with an F atom adopt an orientation similar to that predicted for brassinolide, and the F atom in the "
" position generates an extra hydrogen bond in the predicted binding position.
is a ubiquitous fungus that affects hundreds of plants, resulting in economic losses to the horticulture and fruit industry. The search for new antifungal agents is a matter of current interest. ...Thus, in this work a series of geranylated phenols in which the side alkyl chain has been hydrated have been synthesized, and their activity against
has been evaluated. The coupling of phenol and geraniol has been accomplished under microwave irradiation obtaining the highest reaction yields in the shortest reaction times. Hydration of the side chain was carried out in dioxane with
-toluenesulfonic acid polymer-bound as the catalyst. All synthesized compounds were tested against
using the growth inhibition assay and EC
values were determined. The results show that activity depends on the number and nature of functional groups in the phenol ring and hydration degree of the geranyl chain. The most active compound is 1,4-dihydroquinone with one hydroxyl group attached at the end of the alkyl chain. Results from a molecular docking study suggest that hydroxyl groups in the phenol ring and alkyl chain are important in the binding of compounds to the active site, and that the experimental antifungal activity correlates with the number of H-bond that can be formed in the binding site.
A series of new and known geranylated phenol/methoxyphenol derivatives has been tested in vitro as inhibitor agents of mycelial growth of
. The activity of tested compounds is correlated with the ...nature, number, and position of the substituent group on the aromatic ring. Results indicate that the most active geranylated derivatives are those having two hydroxyl groups (or one ⁻OH and one ⁻OCH₃) attached to the aromatic ring. Interestingly, these derivatives are as active as Metalaxil
, a commonly used commercial fungicide. Thus, our results suggest that some of these compounds might be of agricultural interest due to their potential use as fungicides against
. The effect of structure on fungicide activity is discussed in terms of electronic distribution on both the aromatic ring and side geranyl chain. All tested compounds have been synthesized by direct coupling of geraniol and the respective phenol. Interestingly, new digeranylated derivatives were obtained by increasing the reaction time.
Geranylated hydroquinones and other geranylated compounds isolated from Aplydium species have shown interesting biological activities. This fact has prompted a number of studies where geranylated ...phenol derivatives have been synthesized in order to assay their bioactivities. In this work, we report the synthesis of a series of new hydrated geranylphenols using two different synthetic approaches and their inhibitory effects on the mycelial growth of Botrytis cinerea. Five new hydrated geranylphenols were obtained by direct coupling reaction between geraniol and phenol in dioxane/water and using BF₃·Et₂O as the catalyst or by the reaction of a geranylated phenol with BF₃·Et₂O. Two new geranylated quinones were also obtained. The synthesis and structural elucidation of all new compounds is presented. All hydrated geranylphenols efficiently inhibit the mycelial growth of B. cinerea. Their activity is higher than that observed for non-hydrated compounds. These results indicate that structural modification on the geranyl chain brings about an enhancement of the inhibition effect of geranylated phenol derivatives.
The inhibitory effects on the mycelial growth of plant pathogen Botritys cinerea have been evaluated for a series of geranylphenols substituted with one, two and three methoxy groups in the aromatic ...ring. The results show that the antifungal activity depends on the structure of the geranylphenols, increasing from 40% to 90% by increasing the number of methoxy groups. On the other hand, the acetylation of the -OH group induces a change of activity that depends on the number of methoxy groups. The biological activity of digeranyl derivatives is lower than that exhibited by the respective monogeranyl compound. All tested geranylphenols have been synthesized by direct coupling of geraniol and the respective phenol. The effect of solvent on yields and product distribution is discussed. For monomethoxyphenols the reaction gives better yields when acetonitrile is used as a solvent and AgNO3 is used as a secondary catalyst. However, for di- and trimethoxyphenols the reaction proceeds only in dioxane.
La conciencia cotidiana del tiempo Andrés Mauricio Soto; Otthein Rammstedt
DigitHVM revista digital d'humanitats,
06/2022
28
Journal Article
Recenzirano
Odprti dostop
Traducción de la obra original Alltagsbewußtsein von Zeit de Rammstedt Otthein (1975), publicada en Kölner Zeitschrift für Soziologie und Sozialpsychologie vol. 27(1), pp. 47-63. Traducida por Andrés ...Soto y revisada por Lionel Lewkow.
Providing the context for the evolution of life-history traits, habitat features constrain successful ecological and physiological strategies. In vertebrates, a key response to life's challenges is ...the activation of the Stress (HPA) and Gonadal (HPG) axes. Much of the interest in stress ecology is motivated by the desire to understand the physiological mechanisms in which the environment affects fitness. As reported in the literature, several intrinsic and extrinsic factors affect variability in hormone levels. In both social and non-social animals, the frequency and type of interaction with conspecifics, as well as the status in social species, can affect HPA axis activity, resulting in changes in the reproductive success of animals. We predicted that a social environment can affect both guanaco axes by increasing the secretion of testosterone (T) and Glucocorticoid (GCs) in response to individual social interactions and the energetic demands of breeding. Assuming that prolonged elevated levels of GCs over time can be harmful to individuals, it is predicted that the HPA axis suppresses the HPG axis and causes T levels to decrease, as GCs increase.
All of the data for individuals were collected by non-invasive methods (fecal samples) to address hormonal activities. This is a novel approach in physiological ecology because feces are easily obtained through non-invasive sampling in animal populations.
As expected, there was a marked adrenal (
-value = .3.4e-12) and gonadal (
-value = 0.002656) response due to seasonal variation in
. No significant differences were found in fecal GCs metabolites between males/females*season for the entire study period (
-value = 0.2839). Despite the seasonal activity variation in the hormonal profiles, our results show a positive correlation (
-value = 1.952e-11, COR = 0.50) between the adrenal and gonadal system. The marked endocrine (
= 0.806) and gonad (
= 0.7231) response due to seasonal variation in male guanaco individuals highlights the individual's energetic demands according to life-history strategies. This is a remarkable result because no inhibition was found between the axes as theory suggests. Finally, the dataset was used to build a reactive scope model for guanacos.
Guanacos cope with the trade-off between sociability and reproductive benefits and costs, by regulating their GCs and T levels on a seasonal basis, suggesting an adaptive role of both axes to different habitat pressures. The results presented here highlight the functional role of stress and gonad axes on a critical phase of a male mammal's life-the mating period-when all of the resources are at the disposal of the male and must be used to maximize the chances for reproductive success.
The use of UAV represents a very useful tool for rock mass characterization, particularly in large, unsafe, and not accessible areas characterized by a complex geometry. This investigation was mainly ...focused on mapping discontinuities and characterizing rock masses using UAV photogrammetry, machine learning, including different algorithms, and intact rock laboratory analyses, respectively. To this aim different outcrops from those described as a part of the basement of the Acoculco Caldera Complex, composed by a series of folded limestones were selected. The results indicate that geomechanical and physical properties, together with outcrop information are very important to assign suitable properties to large rock units. In turn, the great number of plots of discontinuity orientation extracted from the 3D point cloud data by the used of our code written in python language allowed to easily identify the presence of a total of seven discontinuity sets, some of them related to the bedding sequence and some others related to shear and tensile stress due to folding.
Highlights
• Discontinuity orientation extracted from the 3D point cloud data, allowed to easily identify the presence of discontinuity sets.
• A detailed characterization of intact rock and discontinuities is presented and discussed.
• This manuscript is accompanied by a code written in python programming language, placed in a public repository.
• Detailed characterization of the properties of the rock mass is necessary to build different conceptual models in the area.
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