A bio-economic modelling project for small-scale milk production systems in South-East Brasil

This paper reports on the development and use of a bioeconomic model to simulate dairy enterprises in the Zona da Mata of Minas Gerais State in south-east Brasil.In view of the relatively small size of the units, each animal within the herd is accounted for on an individual basis and the main biological events and processes are treated stochastically. Within the limits of given herdranges for genetic potentials, actual rates of performance are estimated from the levels of feeding and other management factors. An energy balance approach is used to assess the contributions of pasture, cut forage and concentrates in the diet.The model has been used to help in identifying priority areas for applied research, to explore various combinations of herd potential and level of feeding, the behaviour of different herd sizes and the potential returns from specific technical innovations.     

Effect of storage on secoiridoid and tocopherol contents and antioxidant activity of monovarietal extra virgin olive oils

The degradation of secoiridoid, tocopherol, and antioxidant activity in extra virgin olive oils (EVOOs) was studied during 8 months of storage in closed bottles in the dark, at 40 and 25 degrees C. Picual, Arbequina, Taggiasca, and Colombaia monovarietal EVOOs possessing quite different fatty acid and antioxidant contents were used. The secoiridoid aglycones, namely, the oleuropein and ligstroside derivatives, and alpha-tocopherol decreased following pseudo-first-order kinetics. In all EVOOs oleuropein derivatives were less stable than the corresponding ligstroside derivatives and alpha-tocopherol. Accordingly, overall antioxidant activity decreased following pseudo-first-order kinetics, with rate constants ranging from 0.85 x 10(-)(3) to 4.1 x 10(-)(3) days(-)(1) at 40 degrees C and from 0.8 x 10(-)(3) to 1.5 x 10(-)(3) days(-)(1) at 25 degrees C. According to both the antioxidant activity and the hydrolysis and oxidation indices established by EU regulation to assess EVOO quality, Colombaia oil was the least stable, followed by Taggiasca, Arbequina, and Picual oils. Despite antioxidant degradation, EVOOs with high antioxidant contents were still "excellent" after 240 days of storage at 40 degrees C. These data led to the conclusion that the beneficial properties of EVOOs due to antioxidant activity can be maintained throughout their commercial lives.     

Degradation of chloroplast DNA during natural senescence of maple leaves

The fate of chloroplast DNA (cpDNA) during plastid development and conversion between various plastid types is still not very well understood. This is especially true for the cpDNA found in plastids of naturally senescing leaves. Here, we describe changes in plastid nucleoid structure accompanied with cpDNA degradation occurring during natural senescence of the free-growing deciduous woody species Acer pseudoplatanus L. Natural senescence was investigated using three types of senescing leaves: green (G), yellow-green (YG) and yellow (Y). The extent of senescence was evaluated at the level of photosynthetic pigment degradation, accumulation of starch and plastid ultrastructure. Determination of cpDNA amount was carried out by in planta visualization with 4,6-diamidino-2-phenylindole, by Southern hybridization, and by dot-blot using an rbcL gene probe. During natural senescence, plastid nucleoids undergo structural rearrangements accompanied by an almost complete loss of cpDNA. Furthermore, senescence-associated protein components exhibiting strong binding to an ～10kbp rbcL-containg cpDNA fragment were identified. This interaction might be important for rbcL expression and Rubisco degradation during the course of natural senescence in trees.     

Machine learning methods for estimation the indicators of phosphogypsum influence in soil

Purpose

The full understanding of the effect of mineral waste-based fertilizer in soil is still unrelieved, because of the extreme complex chemical composition and plethora of their action pathways. The purposes of this paper is to quantify the input of PG into the soil ecosystem process, considering the direct effects of PG as a whole on soil environment using of a plethora of chemical, toxicological, and biological tests.

Materials and methods

Greenhouse experiment includes different PG doses (0, 1%, 3%, 7.5%, 15%, 25%, and 40%) and two-time collection points after treatments—7 and 28 days. For each treatment and each time collection point, we measure (i) soil pH, bioavailable (H₂0 and NH₄COOH-extractable) element content (S, P, K, Na, Mg, Ca, Fe, Zn, Sr, Ba, F); (ii) soil enzyme activities—dehydrogenase, urease, acid phosphatase, FDA; (iii) soil CO₂ respiration activity with and without glucose addition; (iv) Eisenia fetida, Sinapis alba, and Avena sativa responses. Finally, we combine the ordinary chemical, toxicology, and biological measuring of soil properties with state-of-the-art mathematical analysis, namely (i) support vector machines (used for prediction), (ii) mutual information test (variable importance tasks), (iii) t-SNE and LLE algorithms (used for unsupervised classification).

Results and discussion

The results show similarity between the 0%, 1%, and 3% PG treatments in all collection times based on the toxicological and biological properties. Beyond 7.5% PG, some biological test was significantly inhibited in response to trace element stress. Among all tested parameters, soil urease activities, soil respiration activities after glucose addition, S. alba root lengths, and E. fetida survival rates show sensitivity to PG addition. Furthermore, the machine learning algorithms revealed that only several elements (mobile and water-soluble forms of Ca, Ba, Sr, S, and Na; water-soluble F) could be responsible to elevated soil toxicity for those indicators. SVR models were able to predict soil biological and ecotoxicity properties, and increasing numbers of randomly selected training examples from 50 to 90% of initial experimental data significantly improved model performance.

Conclusions

At this study, we demonstrate benefits of unsupervised machine learning methods for investigating toxicity of man-made substances in soil that can be further applied to risk assessments of various toxins, which are of significant interest to environmental protection.

     

Biodegradation of humic substances by microscopic filamentous fungi: chromatographic and spectroscopic proxies

Purpose

The study of interactions between humic substances (HSs) and soil filamentous fungi is the key to understanding the sustainable soil functioning. The present work aims to examine the decomposition of HSs by filamentous dark-pigmented fungus Alternaria alternatа under the laboratory conditions and to determine the effect of easily assimilable organic carbon on this process. Analyzing such polydisperse substances like HSs by a complex integrated methodology makes it possible to explore the data on their decomposition by microorganisms.

Materials and methods

To achieve the aforementioned goals, we used chromatographic and spectroscopic approaches: low-pressure size-exclusion and hydrophobic interaction chromatography accompanied by absorption and fluorescence spectroscopy. To determine the effect cometabolism conditions produced on HS decomposition, two types of carbon substrates were added to the nutrient media: easily assimilable organic carbon (standard 0.3% or reduced 0.03% sucrose content) and hardly assimilable organic carbon (HSs), as well as their combinations. Five HS samples of different organic matter origin have been inspected: potassium humates (HPs) and humic acids (HAs) from coal, peat, and lignosulfonate. Correlation matrix and principal component analysis (PCA) were calculated for comprehensive data analysis.

Results and discussion

Transformations of the investigated HSs under fungal cultivation lead to the increase in the low molecular weight fraction, rise of hydrophilic fraction, enlargement of absorbance ratio A₂₅₀/A₃₆₅, shortening of the emission wavelength of the humic-type fluorescence, and growth in the fluorescence quantum yield measured with excitation at 355 nm. A positive correlation was observed between the accumulation of fungal biomass and the degree of HS decomposition. PCA analysis confirms that the difference in the results of HS decomposition largely depends on the sucrose content and the nature of HSs. We divided all the HS samples into four groups according to the degree of HS decomposition: original HS solutions, HPs altered using fungal cultivation at 0.03% sucrose, HAs after fungal cultivation at 0.03% sucrose, and finally, HSs (both HPs and HAs) after fungal cultivation at 0.3% sucrose.

Conclusions

In the laboratory experiments, we showed that (1) the isolated HAs were more effectively degraded than the parent HPs, and this process was more pronounced at a reduced sucrose content, and (2) the decomposition of stable organic compounds (HSs) was activated by the easily assimilable carbon sources (especially 0.3% sucrose) being present. We assume that it is the easily assimilable organic carbon that most likely triggers the HS degradation working as the priming effect in natural environments.

     

Optimization of color and antioxidant activity of peach and nectarine puree: scale-up study from pilot to industrial plant

The effects of an innovative process for the manufacture of peach and nectarine purees on the main quality indices, namely, color, consistency, carotenoid and phenolic content, and antioxidant activity, were studied using a peach cultivar that is optimal for nectar processing (cv. Redhaven) and peach and nectarine varieties that undergo a faster browning degradation. The innovative process, operating the pulping/finishing step at room temperature, was compared to the traditional process of hot pulping/finishing. The study comprised initial trials on a pilot plant scale and scaling up to industrial production of the puree and nectar. The quality of products was analyzed at the time of production and as a function of storage of both the puree and the nectar. With respect to the traditional process, the new process, scaled up to industrial levels, improved the color of peach and nectarine products (by increasing the L* value and decreasing the a* value), whatever the variety studied; maintained almost the same levels of carotenoids, hydroxycinnamates, flavan-3-ols, and flavonols; and reduced the level of cyanidin 3-O-glucoside. The presence of cyanidin 3-O-glucoside was correlated to an unstable and undesirable red hue of the products (even if its concentration was very low in all products), and the decreased level obtained by the innovative process was considered to be positive. On the basis of these results, new technology can be proposed for the processing of fruit varieties that are not suitable for puree production using traditional technology. This opens up two possibilities: (a) utilization of fresh market fruit surplus and (b) processing of selected fruit varieties that are rich in antioxidants but have a high browning potential, such as the Stark Red Gold nectarine. Furthermore, as the positive impact of the new technology is optimal at the beginning of storage, it is particularly suitable for fruit-based products with a short shelf life.     

Acaricidal activity of Calea serrata (Asteraceae) on Boophilus microplus and Rhipicephalus sanguineus

Calea serrata (Asteraceae) is an endemic Southern Brazilian plant species used for religious and medicinal purposes. Previous study revealed the presence of chromenes, a class of natural compounds that possess insecticidal properties. This study reports the effect of the hexane extract from the aerial parts of this plant on egg hatchability, egg production and mortality rates of newly hatched larvae of the cattle tick Boophilus microplus. Larvae of Rhipicephalus sanguineus, the brown dog tick, received the same treatment. The extract was toxic to the eggs of B. microplus and to the larvae of both B. microplus and R. sanguineus.     

Continuous lumbar hemilaminectomy for intervertebral disc disease in an Amur tiger (Panthera tigris altaica)

A 13-yr-old Amur tiger (Panthera tigris altaica) was presented for an acute onset of paraplegia. Spinal imaging that included plain radiographs, myelography, and computed tomography performed under general anesthesia revealed lateralized spinal cord compression at the intervertebral disc space L4-5 caused by intervertebral disc extrusion. This extrusion was accompanied by an extensive epidural hemorrhage from L3 to L6. Therefore, a continuous hemilaminectomy from L3 to L6 was performed, resulting in complete decompression of the spinal cord. The tiger was ambulatory again 10 days after the surgery. This case suggests that the potential benefit of complete spinal cord decompression may outweigh the risk of causing clinically significant spinal instability after extensive decompression.