Maíz Bofo

Se caracteriza por sus mazorcas alargadas y semi elípticas con granos multicolor. Es considerado el maíz sagrado de los pueblos Wixárika (Huichol).

Via: @_SemillasdeVida

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Finally out of reach-  

No bondage, no dependency.  

How calm the ocean,  

Towering the void. 
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Tessho

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On the predictability of infectious disease outbreaks

Scarpino and Petri, 2019.

Infectious disease outbreaks recapitulate biology: they emerge from the multi-level interaction of hosts, pathogens, and environment. Therefore, outbreak forecasting requires an integrative approach to modeling. While specific components of outbreaks are predictable, it remains unclear whether fundamental limits to outbreak prediction exist. Here, adopting permutation entropy as a model independent measure of predictability, we study the predictability of a diverse collection of outbreaks and identify a fundamental entropy barrier for disease time series forecasting. However, this barrier is often beyond the time scale of single outbreaks, implying prediction is likely to succeed. We show that forecast horizons vary by disease and that both shifting model structures and social network heterogeneity are likely mechanisms for differences in predictability. Our results highlight the importance of embracing dynamic modeling approaches, suggest challenges for performing model selection across long time series, and may relate more broadly to the predictability of complex adaptive systems.

Single outbreaks are often predictable. a The average predictability (1 − H^p) for weekly, state-level data from nine diseases is plotted as a function of time-series length in weeks. For each disease, we selected 1000 random starting locations in each time series and calculated the permutation entropy in rolling windows in lengths ranging from 2 to 104 weeks. The solid lines indicate the mean value and the shaded region marks the interquartile range across all states and starting locations in the time series. Although the slopes are different for each disease, in all cases, longer time series result in lower predictability. However, most diseases are predictable across single outbreaks and disease time series cluster together, i.e. there are disease-specific slopes on the relationship between predictability and time-series length. To aid in interpretation, the black dashed line plots the median permutation entropy across 20,000 stochastic simulations of a Susceptible Infectious Recovered (SIR) model, as described in the Supplement. This SIR model would be considered predictable, thus values above the black line might be thought of as in-the-range where model-based forecasts are expected to outperform forecasts based solely on statistical properties of the time-series data. The dark brown, dashed vertical line indicates the time period selected for b. In b, the predictability is shown after 4 months, i.e. 16 weeks, of data for each pathogen. The same procedure was used to generate the permutation entropy as in a. The mean predictability differed both by disease and by geographic location, i.e state (analysis of variance with post hoc Tukey honest significant differences test and correction for multiple comparison, sum of squares (SS) disease = 98.22, degrees of freedom (DF) disease = 8, p-value disease < 0.001; SS location = 94.7, DF location = 53, p-value location < 0.001). The solid line represents the median, boxes enclose the 25th to 75th percentiles of the distributions, and whiskers cover the entire distribution

https://www.nature.com/articles/s41467-019-08616-0 
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Towards an integrative understanding of soil biodiversity

Thakur et al., 2019

Soil is one of the most biodiverse terrestrial habitats. Yet, we lack an integrative conceptual framework for understanding the patterns and mechanisms driving soil biodiversity. One of the underlying reasons for our poor understanding of soil biodiversity patterns relates to whether key biodiversity theories (historically developed for aboveground and aquatic organisms) are applicable to patterns of soil biodiversity. Here, we present a systematic literature review to investigate whether and how key biodiversity theories (species–energy relationship, theory of island biogeography, metacommunity theory, niche theory and neutral theory) can explain observed patterns of soil biodiversity. We then discuss two spatial compartments nested within soil at which biodiversity theories can be applied to acknowledge the scale‐dependent nature of soil biodiversity.

Illustration of spatial compartments in the soil for studying soil biodiversity from micro‐ to macroorganisms. The properties of each compartment that potentially affect the respective biodiversity pattern are listed below the compartments. As we begin to zoom in from soil (S) to soil microsites (S″), the applicability of some biodiversity theories may also change (indicated by thickness of grey bars below the figure). Soil micro‐aggregates are coloured light brown in the S″ compartment; all organisms in S″ are either microorganisms or their predators (e.g. nematodes and protists). Note that microorganisms also can colonize micro‐aggregates as illustrated in S″. Since the temporal scale (t) also co‐varies with spatial scale (Wolkovich et al., 2014), the figure presents three different temporal scales (t1–t3) corresponding to the three spatial scales. f, function.  

https://onlinelibrary.wiley.com/doi/full/10.1111/brv.12567
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Para identificar a los productores y asegurar la calidad del pan, los panaderos de finales del siglo XVIII de la ciudad de Caracas proponen colocar marcas a su producción. Aquí algunas de esas marcas o señales (1787).

Fondo Archivo General de la Nación, sub-fondo “Colonia”, Sección Política y Gobierno”, serie “Gobernación y Capitanía General”, Tomo XXXI, Folios 1 a 24.

Fuente: @HistoriaPapeles

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Insights into the assembly rules of a continent-wide multilayer network     
Mello et al, 2019.

How are ecological systems assembled? Identifying common structural patterns within complex networks of interacting species has been a major challenge in ecology, but researchers have focused primarily on single interaction types aggregating in space or time. Here, we shed light on the assembly rules of a multilayer network formed by frugivory and nectarivory interactions between bats and plants in the Neotropics. By harnessing a conceptual framework known as the integrative hypothesis of specialization, our results suggest that phylogenetic constraints separate species into different layers and shape the network’s modules. Then, the network shifts to a nested structure within its modules where interactions are mainly structured by geographic co-occurrence. Finally, organismal traits related to consuming fruits or nectar determine which bat species are central or peripheral to the network. Our results provide insights into how different processes contribute to the assemblage of ecological systems at different levels of organization, resulting in a compound network topology.

 

The bat–plant multilayer network. By compiling bat–plant interactions (lines) across the Neotropics, we found a compound topology with a strong separation between interaction types (layers) and guilds (modules). The layers represent interactions of frugivory, nectarivory and dual interactions. Modules were detected using the LPA. 

https://www.nature.com/articles/s41559-019-1002-3

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Increasing crop heterogeneity enhances multitrophic diversity across agricultural regions 

Sirami et al., 2019

Agricultural landscape homogenization is a major ongoing threat to biodiversity and the delivery of key ecosystem services for human well-being. It is well known that increasing the amount of seminatural cover in agricultural landscapes has a positive effect on biodiversity. However, little is known about the role of the crop mosaic itself. Crop heterogeneity in the landscape had a much stronger effect on multitrophic diversity than the amount of seminatural cover in the landscape, across 435 agricultural landscapes located in 8 European and North American regions. Increasing crop heterogeneity can be an effective way to mitigate the impacts of farming on biodiversity without taking land out of production.

Agricultural landscape homogenization has detrimental effects on biodiversity and key ecosystem services. Increasing agricultural landscape heterogeneity by increasing seminatural cover can help to mitigate biodiversity loss. However, the amount of seminatural cover is generally low and difficult to increase in many intensively managed agricultural landscapes. We hypothesized that increasing the heterogeneity of the crop mosaic itself (hereafter “crop heterogeneity”) can also have positive effects on biodiversity. In 8 contrasting regions of Europe and North America, we selected 435 landscapes along independent gradients of crop diversity and mean field size. Within each landscape, we selected 3 sampling sites in 1, 2, or 3 crop types. We sampled 7 taxa (plants, bees, butterflies, hoverflies, carabids, spiders, and birds) and calculated a synthetic index of multitrophic diversity at the landscape level. Increasing crop heterogeneity was more beneficial for multitrophic diversity than increasing seminatural cover. For instance, the effect of decreasing mean field size from 5 to 2.8 ha was as strong as the effect of increasing seminatural cover from 0.5 to 11%. Decreasing mean field size benefited multitrophic diversity even in the absence of seminatural vegetation between fields. Increasing the number of crop types sampled had a positive effect on landscape-level multitrophic diversity. However, the effect of increasing crop diversity in the landscape surrounding fields sampled depended on the amount of seminatural cover. Our study provides large-scale, multitrophic, cross-regional evidence that increasing crop heterogeneity can be an effective way to increase biodiversity in agricultural landscapes without taking land out of agricultural production.

 

(A) Traditional and (B) alternative representations of agricultural landscape heterogeneity, focusing either on seminatural heterogeneity or crop heterogeneity, are associated with distinct hypotheses.

https://www.pnas.org/content/early/2019/07/26/1906419116

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Ecological changes with minor effect initiate evolution to delayed regime shifts     

P. Catalina Chaparro-Pedraza  and  André M. de Roos, 2010.

Regime shifts have been documented in a variety of natural and social systems. These abrupt transitions produce dramatic shifts in the composition and functioning of socioecological systems. Existing theory on ecosystem resilience has only considered regime shifts to be caused by changes in external conditions beyond a tipping point and therefore lacks an evolutionary perspective. In this study, we show how a change in external conditions has little ecological effect and does not push the system beyond a tipping point. The change therefore does not cause an immediate regime shift but instead triggers an evolutionary process that drives a phenotypic trait beyond a tipping point, thereby resulting (after a substantial delay) in a selection-induced regime shift. Our finding draws attention to the fact that regime shifts observed in the present may result from changes in the distant past, and highlights the need for integrating evolutionary dynamics into the theoretical foundation for ecosystem resilience.

https://www.nature.com/articles/s41559-020-1110-0 

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What's travel and what good is it? We never disembark from ourselves. 

The true landscapes are those that we ourselves create. I've crossed more seas than anyone. I've seen more mountains than there are on earth. 

The universe isn't mine: it's me.  

Fernando Pessoa
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Soil fungal assemblage complexity is dependent on soil fertility and dominated by deterministic processes

 Junjie Guo et al., 2020

• In the processes controlling ecosystem fertility, fungi are increasingly acknowledged as key drivers. However, our understanding of the rules behind fungal community assembly regarding the effect of soil fertility level remains limited.
• Using soil samples from typical tea plantations spanning c. 2167 km north‐east to south‐west across China, we investigated the assemblage complexity and assembly processes of 140 fungal communities along a soil fertility gradient.
• The community dissimilarities of total fungi and fungal functional guilds increased with increasing soil fertility index dissimilarity. The symbiotrophs were more sensitive to variations in soil fertility compared with pathotrophs and saprotrophs. Fungal networks were larger and showed higher connectivity as well as greater potential for inter‐module connection in more fertile soils. Environmental factors had a slightly greater influence on fungal community composition than spatial factors. Species abundance fitted the Zipf–Mandelbrot distribution (niche‐based mechanisms), which provided evidence for deterministic‐based processes.
• Overall, the soil fungal communities in tea plantations responded in a deterministic manner to soil fertility, with high fertility correlated with complex fungal community assemblages. This study provides new insights that might contribute to predictions of fungal community complexity.

 

https://nph.onlinelibrary.wiley.com/doi/10.1111/nph.16345
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 Bruno Latour - Gaia 2.0/Down to Earth

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Suppose we did out work 
like the snow, quietly, quietly, 
leaving nothing out.

Wendell Berry
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A social–ecological analysis of the global agrifood system 
Oteros-Rozas et al., 2019.

Eradicating world hunger—the aim of Sustainable Development Goal 2 (SDG2)—requires a social–ecological approach to agrifood systems. However, previous work has mostly focused on one or the other. Here, we apply such a holistic approach to depicting the global food panorama through a quantitative multivariate assessment of 43 indicators of food sovereignty and 28 indicators of sociodemographics, social being, and environmental sustainability in 150 countries. The results identify 5 world regions and indicate the existence of an agrifood debt (i.e., disequilibria between regions in the natural resources consumed, the environmental impacts produced, and the social wellbeing attained by populations that play different roles within the globalized agrifood system). Three spotlights underpin this debt: 1) a severe contrast in diets and food security between regions, 2) a concern about the role that international agrifood trade is playing in regional food security, and 3) a mismatch between regional biocapacity and food security. Our results contribute to broadening the debate beyond food security from a social–ecological perspective, incorporating environmental and social dimensions.

https://www.pnas.org/content/early/2019/12/10/1912710116