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Digital platforms such as Uber, Rappi or Airbnb impose a labor model where workers are not recognized as such and do not have minimum rights. They are part of platform capitalism, a form of capital that uses digital technologies to impose a precarious employment relationship. However, faced with this model, application workers are beginning to organize and demand rights. In this article, I examine the ideology that platforms promote and the resistances of app distributors. I argue that, in the face of the imagined individualism of digital platforms, delivery workers are recreating forms of community. They have not been passive or totally subaltern but are displaying different forms of antagonism and autonomy. This paper is based on qualitative research with interviews of key informants and analysis of the documents of collectives and groups of Mexican delivery workers, both in Mexico City and in New York. [ABSTRACT FROM AUTHOR]

In Mexican exterior relationships in the early twentieth century, two types of triangular relations existed: the balance between United States and Europe, and the antagonism between two powers in order to defend their economic and political interests. From the second kind, the French-German case is archetypal, because both were enemies, and they wanted to strengthen their trade and cultural relationships with Mexico. The triangle is interesting to know the presence of the Germans by the sight of the adversary: the French. The French observed the German activities in Mexico with attention, for the danger they represented for French cultural and commercial interests. Between 1925 and 1933, in spite of being a more peaceful time, the opposition between Germans and French remained. Therefore, it is important to consider the motives of competition in diplomatic, cultural and economic areas. It is also relevant to analyse how French perceived the Germans in Mexico, and what this illustrates about the links between Germany and Mexico, through trilateral relations [ABSTRACT FROM AUTHOR]

Within the framework of Latin American post-war structuralism, the global economy was the grounds of antagonism between a central (industrialized) pole and the periphery (providers of primary goods). This paper argues that addressing the specific way this antagonism is reproduced in the historical conditions of new capitalism requires considering the emergence of a chain-shaped structural logic, which differentiates activities of knowledge creation from those of knowledge reproduction within distinct productive sectors. This chain logic does not challenge the concept of structure, in terms of a sectoral differentiation in post-war capitalist production, but rather imposes it as a dominant norm. [ABSTRACT FROM AUTHOR]

The objective of this work was to select promising strains of Trichoderma asperellum Samuels, Lieckfeldt & Nirenberg for the control of Fusarium spp. pathogens of chickpea (Cicer arietinum L.). The antagonistic activity (competition for space, mycoparasitism, and antibiosis) of the Trichoderma strains was evaluated by the dual culture method and the antibiosis by the suspension method (volatile metabolites) and by filtrates (non-volatile metabolites) of the antagonist. All the Trichoderma strains tested showed high competitive capacity for space vs Fusarium isolates, except Ta.85. Trichoderma strains Ta.3, Ta.12, Ta.25, Ta.78, and Ta.79 stood out for their mycoparasitism in Fusarium nygamai (F-11) and Fusarium oxysporum f. sp. ciceri (F-50). Strain Ta. 1 showed its mycoparasitic effect on the isolates of Fusarium oxysporum f. sp. ciceri (F-50) and (F-51). Strains Ta.1, Ta.28, Ta.78 and Ta.79 were outstanding due to their metabolic action against the Fusarium isolates. The action of the volatile metabolites excreted by Trichoderma on the Fusarium isolates growth was variable. Some Trichoderma strains, such as Ta.56 against F-11, Ta.1 against F-50, and Ta.28 against F-50, and F-5l, stood out for showing higher values of inhibition of Fusarium growth and stability in the results, due to the lower variability of their variances. The non-volatile metabolites of the Ta.79 strain had the highest inhibition values against the pathogen isolates, being this strain the most stable. From the comprehensive analysis of all mechanisms studied, the strain Ta.79 was the most promising to control Fusarium spp. [ABSTRACT FROM AUTHOR]

Infestation of gregarines from genus Nematopsis in Pacific white shrimp Litopenaeus vannamei is commonly associated with a decrease in production and low weight, as well as a possible predisposition to viral infections. The goal of our past research was to evaluate the effect of the Nematopsis sp. gregarine parasitosis on the growth of farm-grown Litopenaeus vannamei shrimp. Four cages were built with PVC pipes and plastic screens with a 6mm light diameter, 1,7m in height, and 1,5m in width and length (2,23 m³), and were installed in a farm-growing area in La Pesca, Tamaulipas. Twenty-nine previously weighed shrimp, L. vannamei, were placed in each cage. These had a "2" (6 to 10 parasites per shrimp) degree of infestation severity by Nematopsis sp. The shrimp in 2 cages were fed for 5 days with the farm feed and 6g/kg of sodium monensin. The shrimp in the remaining cages were fed with commercial feed. After 5 days, the shrimp in the 4 cages were fed with a balanced feed for 38 days. After this, the biomass of each cage was recorded. The shrimp in the control cages weighed an average of 7,12g at the beginning of research and 9,27g at the end, and the treated shrimp weighed 7,09g and 9,88g, respectively. The non-treated shrimp gained 2,5g and the treated shrimp gained 2,79g. This present research shows that the negative effect on the shrimp growth caused by Nematopsis sp. infestation can be reversed if the infected shrimp are treated against infestation with sodium monensin, which possesses a therapeutic effect that eliminated the infestation without affecting the shrimp growth. [ABSTRACT FROM AUTHOR]

The aim of this work was to determine the action modes of Trichoderma spp. against Didymella bryoniae (Fuckel) Rehm. The competition by the substrate, antibiosis and mycoparasitism of Trichoderma asperellum Samuels (Ta), Trichoderma harzianum Rifai (Th) and Trichoderma sp. (T.) was assessed by the dual culture method. After 72 hours, all the isolates showed an inhibitory effect over the pathogen growth higher than 50%. The isolates Ta. 12, Ta. 79, Ta. 85 and T. 81 grew more than 75% of the plate area; thus, they were placed in the class 1 of Bell's scale. The growth rate of the two latter isolates increased from the 72 h, which could be related to attractive compounds emitted by the pathogen. Th A-34 and Ta. 85 presented the best indicators of parasitism with three types of hyphal interaction (coiling, vacuolization and penetration). The volatile metabolites produced by Th-34, Ta. 79 and Ta. 85 and those non-volatile emanating from Th A-34, Ta. 79 and T. 81 inhibited the pathogen growth from the 72h. According to the modes of action exhibited by the different isolates, Th A-34 and Ta. 85 were chosen as the best isolates for the control of D. bryoniae. They are emerging as potential candidates for biopesticide active ingredients, although their evaluation in the control of D. bryoniae under field conditions is required. [ABSTRACT FROM AUTHOR]

The antagonistic effect of a native isolate of Trichoderma spp., was evaluated for Sclerotium rolfsii Sacc. control, under in vitro and glasshouse conditions, at the North Region of Guerrero State. Twelve Trichoderma spp. native isolates were obtained (2 from Santa Teresa and 10 from Tlaxmalac, Gro), of which six were selected (Tcn-4, Tcn-5, Tcn-6, Tcn-7, Tcn-8 and Tcn-11) by the cellophane paper method. Under in vitro conditions, the percentage of inhibition varied from 10.0 to 94.4%; it was registered using the paired cultures technique, antagonism class two with isolate Tcn-11, in these conditions the growth of the plant pathogen was inhibited and decreased its development over the 80% of the medium culture surface in the Petri box. The native strain Tcn-11 morphologically and genetically identified as T. harzianum Rifai was evaluated under glasshouse conditions and compared with a strain collection (Thzcf-12) and a commercial fungicide at three inoculation times. The plant pathogen S. rolfsii was not sufficiently aggressive to cause death of the peanut plant; however, negative effects were observed on plant development and seed production. The strains Tcn-11 and Thzcf-12 were able to contribute to the development of the peanut plant and to help protect it from infection of S. rolfsii in a more efficient way than the fungicidal pentacloronitrobenzene (PCNB). [ABSTRACT FROM AUTHOR]

The aim of this work was to determine the potential of Tsukamurella paurometabola C-924 as a biological control agent of phytopathogenic fungi by its in vitro evaluation on the culture media Agar Triptone Soy (ATS) and Potato Dextrose Agar. The antagonistic activity was determined by measuring the diameter of the fungal colonies grown in presence of the bacterium every 24 hours; the inhibition percentages were calculated by comparing each diameter of these colonies with those of their respective controls grown in absence of the bacterium. T. paurometabola C-924 showed an antagonistic activity on both culture media. The highest inhibition values were determined on ATS against Alternaria longipes (Ellis and Everh.), Bipolaris oryzae (Breda de Hann), Colletotrichum gloesporioides (Penz). Fusarium oxysporum f. sp. cubense (E.F. Sm), Pestalotia palmarum (Cooke) and Thielaviopsis paradoxa (De Seynes). On both culture media, the lowest inhibition percentage was found against Pythium debaryanum (R. Hesse). The results suggested that T. paurometabola C924 had in vitro potential as an antagonistic agent against the phytopathogenic fungi tested. [ABSTRACT FROM AUTHOR]

Six Trichoderma spp. native strains were identified to specie and studied to determine their growth rate and antagonism against plant pathogen fungi. The strains were cultivated on Potato Dextrose Agar to determine their morphological characteristics and growth rate. Molecular analysis was carried out to identify their species. The antagonistic activity was tested by the dual cultures confrontation method. Although morphological characteristics of strains were similar to T. harzianum and T. viride, the molecular analysis showed that strains TC74, TC74M, T341, T359 and T479, were T. asperellum and T397 was T. longibrachiatum. Trichoderma strains mean growth rate at 25 ºC ranged from 12 to 17 mmd-1. Inhibition of the B. cinerea growth ranged from 60% to 75% and mycelium overgrown from 25% to 100%. Inhibition of R. solani growth ranged from 34% to 52% and overgrown from 15% to 100%. Antagonistic activity of T. asperellum TC74, T341 and T359 was similar to reference strains T22 and Th. The same three strains inhibited the M. phaseolina growth from 44% to 64%, R. solani from 51% to 59%, P. omnivora 28% to 37% and Fusarium sp. 5% to 14%. [ABSTRACT FROM AUTHOR]

In this study we evaluated the antagonistic activity and protection of seedlings in vitro of the ascomycete Xylaria poitei, and its antagonistic activity in combination with an unknown ascomycete (AD) against P. capsici, the cause of wilt in pepper. Xylaria poitei protected pepper seedlings and allowed 58.3% survival of seedlings, while the oomycete caused 100% mortality, besides this fungus inhibited the mycelial growth of P. capsici up to 49.6% in one of the experiments where they settled dual confrontations. In triple confrontations both ascomycetes increase slightly their inhibition at 12 days of confortation against P. capsici, and still maintain the inhibition of the oomycete four days later. It was observed that both ascomycetes stimulare or inhibit each other growth at some time during the evaluation of confortation. The potato dextrose liquid medium exposed to the growth of X. poitei (filtrate) has low activity against the mycelial growth of P. capsici. The above results indicate that the antagonistic activity of both ascomycetes againstbP. capsici increases when they grow in combination with respect to the dual confrontations, and suggest that the antagonistic activity of X. poitei is stimulated by the presence of the oomycete. [ABSTRACT FROM AUTHOR]