Equilibrium analysis for an epidemic model with a reservoir for infection

We consider a system of non-linear differential equations describing the spread of an epidemic in two interacting populations. The model assumes that the epidemic spreads within the first population, which in turn acts as a reservoir of infection for the second population. Weexplore the conditions under which the epidemic is endemic in both populations and discuss the global asymptotic stability of the endemic equilibrium using a Lyapunov function and results established for asymptotically autonomous systems. We discuss monkeypox as an example of an emerging disease that can be modelled in this way and present some numerical results representing the model and its extensions

The Momentum of Human Behavior in a Natural Setting

Adults with mental retardation in a group home received popcorn or coffee reinforcers for sorting plastic dinnerware. In Part 1 of the experiment, reinforcers were dispensed according to a variable-interval 60-s schedule for sorting dinnerware of one color and according to a variable-interval 240-s schedule for sorting dinnerware of a different color in successive components of a multiple schedule. Sorting rates were similar in baseline, but when a video program was shown concurrently, sorting of dinnerware was more resistant to distraction when correlated with a higher rate of reinforcement. In Part 2 of the experiment, popcorn or coffee reinforcers were contingent upon sorting both colors of dinnerware according to variable-interval 60-s schedules, but additional reinforcers were given independently of sorting according to a variable-time 30-s schedule during one dinnerware-color component. Baseline sorting rate was lower but resistance to distraction by the video program was greater in the component with additional variable-time reinforcers. These results demonstrate that resistance to distraction depends on the rate of reinforcers obtained in the presence of component stimuli but is independent of baseline response rates and response-reinforcer contingencies. Moreover, these results are similar to those obtained in laboratory studies with pigeons, demonstrating that the determination of resistance to change by stimulus-reinforcer relations is not confined to controlled laboratory settings or unique to the pigeon

Performance of grape marc and organic residues compost as substrate in lettuce (Lactuca sativa) seedlings = Eficiencia del compost de orujo de uva y residuos orgánicos como sustrato en plantines de lechuga (Lactuca sativa)

Composting is an aerobic process used to treat organic residues, which results in a high quality product, able to be adopted as plant substrate or soil amendment. In the present study, the performance of compost on the germination and biomass of Lactuca sativa var Grand rapids seedlings, with and without fertilization, was evaluated. The two types of composts used were prepared from two different raw materials: grape marc and a mixture of grape marc, goat manure, leaves and alfalfa. The experiment was carried out in seedling trays, in a split plot design with two factors (fertilization and substrate) and four repetitions. Sand were used as control and a commercial substrate as traditional treatment. Results indicated that fertilization had not significant effect on germination, but increased seedling biomass. Both compost also increased lettuce biomass, with the highest values obtained in mixture compost treatments. Only sand produced the lowest germination values, while no differences were detected among the other substrates. Compost mixture showed the highest seedling biomass, suggesting a higher quality as a plant substrate. It is necessary to perform further analyses and studies with different organic residues in order to determine physico-chemical and biological properties to evaluate the quality of the product obtained.El compostaje permite reducir y reciclar residuos orgánicos, generando un producto apto para ser utilizado como sustrato para el crecimiento de plantines florales y hortí-colas o como enmienda de suelos. En el presente trabajo, se evaluó el efecto del compost elaborado a partir de orujo de uva agotado y de una mezcla de orujo, guano de cabra, hojas y alfalfa, sobre la germinación y biomasa de plantines de Lactuca sativa var Grand rapids, con y sin fertilización. Se trabajó en bandejas de siembra con un diseño de parcelas divididas con dos factores (sustrato y fertilización), utilizando, arena como control y un sustrato comercial como tratamiento tradicional. Los resultados indicaron que la fertilización no tuvo efecto significativo sobre la germinación, obteniéndose los menores valores con la arena, sin encontrarse diferencias entre el resto de los sustratos. Por otro lado, ambos tipos de compost produjeron mayor biomasa que el sustrato comercial y la arena, efecto que se incrementó con la fertilización. El compost mezcla fue el sustrato que produjo el mayor crecimiento de plantines de lechuga, lo que indicaría una mayor calidad para ser utilizado como sustrato. Es necesario continuar con estudios para determinar las propiedades fisicoquímicas y biológicas del compost que permitan evaluar la calidad de producto obtenido.EEA MendozaFil: Funes Pinter, Mariano Ivan. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Mendoza; Argentina. Universidad Nacional de Cuyo. Facultad Ciencias Agrarias; ArgentinaFil: Aguado, German Dario. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Mendoza; ArgentinaFil: De Biazi, Federico Sebastian. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Mendoza; Argentina.Fil: Fernández, Ana Sofía. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Mendoza; Argentina.Fil: Martinez, Laura Elizabeth. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Mendoza; Argentina. Universidad Nacional de Cuyo. Facultad Ciencias Agrarias; ArgentinaFil: Uliarte, Ernesto Martin. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Mendoza; Argentin

Making or Breaking Metal- Dependent Catalytic Activity: The Role of Stammers in Designed Three- Stranded Coiled Coils

While many life- critical reactions would be infeasibly slow without metal cofactors, a detailed understanding of how protein structure can influence catalytic activity remains elusive. Using de novo designed three- stranded coiled coils (TRI and Grand peptides formed using a heptad repeat approach), we examine how the insertion of a three residue discontinuity, known as a stammer insert, directly adjacent to a (His)3 metal binding site alters catalytic activity. The stammer, which locally alters the twist of the helix, significantly increases copper- catalyzed nitrite reductase activity (CuNiR). In contrast, the well- established zinc- catalyzed carbonic anhydrase activity (p- nitrophenyl acetate, pNPA) is effectively ablated. This study illustrates how the perturbation of the protein sequence using non- coordinating and non- acid base residues in the helical core can perturb metalloenzyme activity through the simple expedient of modifying the helical pitch adjacent to the catalytic center.The addition of a stammer discontinuity within a de novo designed 3SCC containing a symmetric (His)3 metal binding site enhances copper nitrite reductase activity and ablates zinc esterase activity. These results suggest catalytic activity of designed α- helical systems can be modulated by inclusion of discontinuity insertions and deletions.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/163447/3/anie202008356-sup-0001-misc_information.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/163447/2/anie202008356_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/163447/1/anie202008356.pd

The dynamics of animal social networks: Analytical, conceptual, and theoretical advances

Social network analysis provides a broad and complex perspective on animal sociality that is widely applicable to almost any species. Recent applications demonstrate the utility of network analysis for advancing our understanding of the dynamics, selection pressures, development, and evolution of complex social systems. However, most studies of animal social networks rely primarily on a descriptive approach. To propel the field of animal social networks beyond exploratory analyses and to facilitate the integration of quantitative methods that allow for the testing of ecologically and evolutionarily relevant hypotheses, we review methodological and conceptual advances in network science, which are underutilized in studies of animal sociality. First, we highlight how the use of statistical model- ing and triadic motifs analysis can advance our understanding of the processes that structure networks. Second, we discuss how the consideration of temporal changes and spatial constraints can shed light on the dynamics of social networks. Third, we consider how the study of variation at multiple scales can potentially transform our understanding of the structure and function of animal networks. We direct readers to analytical tools that facilitate the adoption of these new concepts and methods. Our goal is to provide behavioral ecologists with a toolbox of current methods that can stimulate novel insights into the ecological influences and evolutionary pressures structuring networks and advance our understanding of the proximate and ultimate processes that drive animal sociality

The dynamics of animal social networks: Analytical, conceptual, and theoretical advances

Social network analysis provides a broad and complex perspective on animal sociality that is widely applicable to almost any species. Recent applications demonstrate the utility of network analysis for advancing our understanding of the dynamics, selection pressures, development, and evolution of complex social systems. However, most studies of animal social networks rely primarily on a descriptive approach. To propel the field of animal social networks beyond exploratory analyses and to facilitate the integration of quantitative methods that allow for the testing of ecologically and evolutionarily relevant hypotheses, we review methodological and conceptual advances in network science, which are underutilized in studies of animal sociality. First, we highlight how the use of statistical model- ing and triadic motifs analysis can advance our understanding of the processes that structure networks. Second, we discuss how the consideration of temporal changes and spatial constraints can shed light on the dynamics of social networks. Third, we consider how the study of variation at multiple scales can potentially transform our understanding of the structure and function of animal networks. We direct readers to analytical tools that facilitate the adoption of these new concepts and methods. Our goal is to provide behavioral ecologists with a toolbox of current methods that can stimulate novel insights into the ecological influences and evolutionary pressures structuring networks and advance our understanding of the proximate and ultimate processes that drive animal sociality

Differential course of HIV-1 infection and apolipoprotein E polymorphism

Abstract We studied the course of infection with human immunodeficiency virus type 1 (HIV-1) in relation to apolipoprotein E (APOE) polymorphism found for 209 Italians treated at Infectious Disease Clinics in Rome and Modena. Clinically, patients were classified into four groups according to the yearly rate of decline in CD4+ cell count (LTNP: long-term non-progression; SLOW, 'NORMAL' or RAPID). Patients at both extremes of the clinical spectrum, i.e. those who rapidly progressed to AIDS and those with stable high CD4 cell counts, had few APOE ɛ4 and ɛ2 alleles (P = 0.04). Detailed clinical information was then used to construct four model-based clinical profiles using grade-of-membership analysis (GoM), predictive of APOE genotypic frequencies: 1. The clinical profile associated with good long-term prognosis lacked ɛ2 (P=0.01); 2. Disease progression to AIDS was associated with ɛ4 and ɛ2, most evident for zidovudine-lamivudine regimens without a protease inhibitor (P = 0.03); and, 3. AIDS patients had low ɛ4 and ɛ2 frequencies, consistent with a high mortality rate among ɛ4+ and ɛ2+ AIDS patients. These findings suggest allele-specific immunomodulatory effects involving inherited APOE isoform important enough to alter the clinical course of HIV infection and, possibly, drug efficacy. They imply a connection between lipid metabolism and immunity potentially relevant to common disorders

Making or Breaking Metal- Dependent Catalytic Activity: The Role of Stammers in Designed Three- Stranded Coiled Coils

While many life- critical reactions would be infeasibly slow without metal cofactors, a detailed understanding of how protein structure can influence catalytic activity remains elusive. Using de novo designed three- stranded coiled coils (TRI and Grand peptides formed using a heptad repeat approach), we examine how the insertion of a three residue discontinuity, known as a stammer insert, directly adjacent to a (His)3 metal binding site alters catalytic activity. The stammer, which locally alters the twist of the helix, significantly increases copper- catalyzed nitrite reductase activity (CuNiR). In contrast, the well- established zinc- catalyzed carbonic anhydrase activity (p- nitrophenyl acetate, pNPA) is effectively ablated. This study illustrates how the perturbation of the protein sequence using non- coordinating and non- acid base residues in the helical core can perturb metalloenzyme activity through the simple expedient of modifying the helical pitch adjacent to the catalytic center.The addition of a stammer discontinuity within a de novo designed three- stranded coiled coil containing a symmetric (His)3 metal binding site enhances copper nitrite reductase activity and ablates zinc esterase activity. These results suggest catalytic activity of designed α- helical systems can be modulated by inclusion of discontinuity insertions and deletions.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/163477/3/ange202008356_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/163477/2/ange202008356-sup-0001-misc_information.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/163477/1/ange202008356.pd

Social tipping points in animal societies

Animal social groups are complex systems that are likely to exhibit tipping points—which are defined as drastic shifts in the dynamics of systems that arise from small changes in environmental conditions—yet this concept has not been carefully applied to these systems. Here we summarize the concepts behind tipping points and describe instances in which they are likely to occur in animal societies. We also offer ways in which the study of social tipping points can open up new lines of inquiry in behavioral ecology and generate novel questions, methods, and approaches in animal behavior and other fields, including community and ecosystem ecology. While some behaviors of living systems are hard to predict, we argue that probing tipping points across animal societies and across tiers of biological organization—populations, communities, ecosystems—may help to reveal principles that transcend traditional disciplinary boundaries

Elaboración de compost, té de compost y biol para su uso como fertilizantes y controladores de enfermedades en plantas

Se evaluó la calidad de compost (elaborado con orujo de uva agotado, guano de cabra, hojas, y alfalfa, en pilas volteadas), té de compost aireado, no aireado, y biol. Durante el proceso de compostaje se evaluó la influencia de una cubierta plástica transparente, en el producto final, variables físico-químicas y biológicas, y la calidad como sustrato en lechuga, y en los productos líquidos, su capacidad fertilizante en plantas y de control in vitro de Botrytis cinerea. La cubierta plástica afectó negativamente la presencia de algunos microorganismos. El compost presentó mayor calidad nutricional con valores de biomasa en lechuga superiores al sustrato comercial. Las plantas tratadas con biol presentaron valores de biomasa similares a los de un fertilizante comercial, y todos los productos controlaron el crecimiento de B. cinerea. Los resultados indican que estos bioinsumos presentan una gran potencialidad para ser utilizados en cultivos.In the present study, compost (acquired mixing grape marc, goat manure, leaves and alfalfa, in turned piles), aerated and no aerated compost tea, and bioslurry quality was tested. We evaluated, during composting process, a transparent plastic cover effect; in the final product, physicochemical, biological and substrate quality; and in liquid products, fertilizer quality and in vitro biocontrol capacity of Botrytis cinerea. Plastic cover negatively affected microorganisms activity. Compost presented the highest nutrient concentration, with superior plant biomass values respect to a commercial substrate. Bioslurry treatments presented plant biomass values similar to a commercial fertilizer, and all liquid products controlled B. cinerea growth. Our results suggest that the bioinsumes present the potentiality to be used in crops.EEA MendozaFil: Funes Pinter, Mariano Ivan. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Mendoza; ArgentinaFil: Funes Pinter, Mariano Ivan. Universidad Nacional de Cuyo. Facultad Ciencias Agrarias; ArgentinaFil: Fernández, Ana Sofía. Universidad Nacional de Cuyo. Facultad Ciencias Agrarias; ArgentinaFil: Hernández, Ana. Universidad Nacional de Cuyo. Facultad Ciencias Agrarias; ArgentinaFil: Aroca, Matías. Universidad Nacional de Cuyo. Facultad Ciencias Agrarias; ArgentinaFil: González Gallerano, Constanza. Universidad Nacional de Cuyo. Facultad Ciencias Agrarias; ArgentinaFil: Arias, María Fernanda. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Mendoza; ArgentinaFil: Escoriaza, Maria Georgina. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Mendoza; ArgentinaFil: Longone, Maria Valeria. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Mendoza; ArgentinaFil: Pisi, Gabriel Enrique. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Mendoza; ArgentinaFil: Martinez, Laura Elizabeth. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Mendoza; ArgentinaFil: Martinez, Laura Elizabeth. Universidad Nacional de Cuyo. Facultad Ciencias Agrarias; ArgentinaFil: Uliarte, Ernesto Martin. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Mendoza; Argentin