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Victus : the fall of Barcelona
\"A sweeping tale of heroism, treason, war, love, pride, and regret that culminates in the tragic fall of a legendary city, illustrated with battle diagrams, portraits of political figures, and priceless maps of the old city of Barcelona.\"--Publisher's website.
Book
Spontaneous persistent activity and inactivity in vivo reveals differential cortico-entorhinal functional connectivity
Understanding the functional connectivity between brain regions and its emergent dynamics is a central challenge. Here we present a theory-experiment hybrid approach involving iteration between a minimal computational model and in vivo electrophysiological measurements. Our model not only predicted spontaneous persistent activity (SPA) during Up-Down-State oscillations, but also inactivity (SPI), which has never been reported. These were confirmed in vivo in the membrane potential of neurons, especially from layer 3 of the medial and lateral entorhinal cortices. The data was then used to constrain two free parameters, yielding a unique, experimentally determined model for each neuron. Analytic and computational analysis of the model generated a dozen quantitative predictions about network dynamics, which were all confirmed in vivo to high accuracy. Our technique predicted functional connectivity; e. g. the recurrent excitation is stronger in the medial than lateral entorhinal cortex. This too was confirmed with connectomics data. This technique uncovers how differential cortico-entorhinal dialogue generates SPA and SPI, which could form an energetically efficient working-memory substrate and influence the consolidation of memories during sleep. More broadly, our procedure can reveal the functional connectivity of large networks and a theory of their emergent dynamics.
Cortico-entorhinal interactions remain poorly understood. Here, the authors demonstrate that a model of interacting networks predicts spontaneous persistent activity and inactivity in the medial, but not lateral, entorhinal cortex in vivo.
Journal Article
Are adaptations self-organized, autonomous, and harmonious? Assessing the social–ecological resilience literature
The paper analyzes how adaptability (adaptive capacity and adaptations) is constructed in the literature on resilience of social–ecological systems (SES). According to some critics, this literature views adaptability as the capacity of SES to self-organize in an autonomous harmonious consensus-building process, ignoring strategies, conflicting goals, and power issues. We assessed 183 papers, coding two dimensions of adaptability: autonomous vs. intentional and descriptive vs. normative. We found a plurality of framings, where 51% of the papers perceived adaptability as autonomous, but one-third constructed adaptability as intentional processes driven by stakeholders; where social learning and networking are often used as strategies for changing power structures and achieving sustainability transformations. For the other dimension, adaptability was used normatively in 59% of the assessed papers, but one-third used descriptive framings. We found no evidence that the SES literature in general assumes a priori that adaptations are harmonious consensus-building processes. It is, rather, conflicts that are assumed, not spelled out, and assertions of “desirable” that are often not clarified by reference to policy documents or explicit normative frameworks. We discuss alternative definitions of adaptability and transformability to clarify or avoid the notion of desirability. Complex adaptive systems framing often precludes analysis of agency, but lately self-organization and emergence have been used to study actors with intentions, strategies, and conflicting interests. Transformations and power structures are increasingly being addressed in the SES literature. We conclude that ontological clashes between social science and SES research have resulted in multiple constructive pathways.
Journal Article
Post-copulatory competition in a social monogamy system: Sperm morphology correlates with components of reproductive success
Males in socially monogamous species can achieve reproductive success through multiple tactics- by defending paternity within the social nest and siring extra-pair offspring, or both. Previous studies have found that sperm morphology may differentially affect fertilization success in extra-pair compared to within-pair matings; therefore, we explored whether sperm morphological traits can predict the probability of success within components of reproductive success. Here, we measured sperm component traits (head length and flagellum length) and derived traits (total length and flagellum:head ratio) in free-living Mountain White-crowned Sparrows (Zonotrichia leucophrys oriantha) and examined how these morphological traits relate to extra-pair and within-pair reproductive components of reproductive success. We found no evidence for correlations between sperm morphology and total seasonal reproductive success. However, we did find that sperm morphology appeared to be associated with whether a male was successful at acquiring extra-pair offspring or defending his own paternity within his nest: males that achieved extra-pair success had longer flagella and longer total length of sperm cells compared to males that did not sire outside of their social nest. In contrast, males that successfully defended all paternity within their social nest tended to have shorter heads and larger flagellum:head ratios compared to males that lost paternity in their social nest. While these patterns suggest that different sperm traits may be linked to success in different components of reproductive success, they should be interpreted with caution given the exploratory nature of this study and limited sample size, and further investigation is warranted.
Journal Article
Antimicrobial properties of chitosan from different developmental stages of the bioconverter insect Hermetia illucens
Growing antimicrobial resistance has prompted researchers to identify new natural molecules with antimicrobial potential. In this perspective, attention has been focused on biopolymers that could also be functional in the medical field. Chitin is the second most abundant biopolymer on Earth and with its deacetylated derivative, chitosan, has several applications in biomedical and pharmaceutical fields. Currently, the main source of chitin is the crustacean exoskeleton, but the growing demand for these polymers on the market has led to search for alternative sources. Among these, insects, and in particular the bioconverter
Hermetia illucens
, is one of the most bred. Chitin can be extracted from larvae, pupal exuviae and dead adults of
H. illucens
, by applying chemical methods, and converted into chitosan. Fourier-transformed infrared spectroscopy confirmed the identity of the chitosan produced from
H. illucens
and its structural similarity to commercial polymer. Recently, studies showed that chitosan has intrinsic antimicrobial activity. This is the first research that investigated the antibacterial activity of chitosan produced from the three developmental stages of
H. illucens
through qualitative and quantitative analysis, agar diffusion tests and microdilution assays, respectively. Our results showed the antimicrobial capacity of chitosan of
H. illucens,
opening new perspectives for its use in the biological area.
Journal Article
Spontaneous persistent activity in entorhinal cortex modulates cortico-hippocampal interaction in vivo
Persistent activity can mediate working memory during behavior. Here, the authors report persistent activity during sleep, occurring spontaneously in medial entorhinal cortex layer III (MECIII) neurons' membrane potential. This persistent activity excited hippocampal CA1 neurons. Thus, persistent activity in MECIII contributes to cortico-hippocampal interaction, which could serve several important mnemonic functions.
Persistent activity is thought to mediate working memory during behavior. Can it also occur during sleep? We found that the membrane potential of medial entorhinal cortex layer III (MECIII) neurons, a gateway between neocortex and hippocampus, showed spontaneous, stochastic persistent activity
in vivo
in mice during Up-Down state oscillations (UDS). This persistent activity was locked to the neocortical Up states with a short delay, but persisted over several cortical UDS cycles. Lateral entorhinal neurons did not show substantial persistence, and current injections similar to those used
in vitro
failed to elicit persistence
in vivo
, implicating network mechanisms. Hippocampal CA1 neurons' spiking activity was reduced during neocortical Up states, but was increased during MECIII persistent states. These results provide, to the best of our knowledge, the first direct evidence for persistent activity in MECIII neurons
in vivo
and reveal its contribution to cortico-hippocampal interaction that could be involved in working memory and learning of long behavioral sequences during behavior, and memory consolidation during sleep.
Journal Article
Characterization of chitin and chitosan derived from Hermetia illucens, a further step in a circular economy process
Due to their properties and applications, the growing demand for chitin and chitosan has stimulated the market to find more sustainable alternatives to the current commercial source (crustaceans). Bioconverter insects, such as
Hermetia illucens
, are the appropriate candidates, as chitin is a side stream of insect farms for feed applications. This is the first report on production and characterization of chitin and chitosan from different biomasses derived from
H. illucens
, valorizing the overproduced larvae in feed applications, the pupal exuviae and the dead adults. Pupal exuviae are the best biomass, both for chitin and chitosan yields and for their abundance and easy supply from insect farms. Fourier-transform infrared spectroscopy, X-ray diffraction and scanning electron microscope analysis revealed the similarity of insect-derived polymers to commercial ones in terms of purity and structural morphology, and therefore their suitability for industrial and biomedical applications. Its fibrillary nature makes
H. illucens
chitin suitable for producing fibrous manufacts after conversion to chitin nanofibrils, particularly adults-derived chitin, because of its high crystallinity. A great versatility emerged from the evaluation of the physicochemical properties of chitosan obtained from
H. illucens
, which presented a lower viscosity-average molecular weight and a high deacetylation degree, fostering its putative antimicrobial properties.
Journal Article
Self-Organized Governance Networks for Ecosystem Management
Governance networks play an increasingly important role in ecosystem management. The collaboration within these governance networks can be formalized or informal, top-down or bottom-up, and designed or self-organized. Informal self-organized governance networks may increase legitimacy if a variety of stakeholders are involved, but at the same time, accountability becomes blurred when decisions are taken. Basically, democratic accountability refers to ways in which citizens can control their government and the mechanisms for doing so. Scholars in ecosystem management are generally positive to policy/governance networks and emphasize its potential for enhancing social learning, adaptability, and resilience in social-ecological systems. Political scientists, on the other hand, have emphasized the risk that the public interest may be threatened by governance networks. I describe and analyze the multilevel governance network of Kristianstads Vattenrike Biosphere Reserve (KVBR) in Southern Sweden, with the aim of understanding whether and how accountability is secured in the governance network and its relation to representative democracy. The analysis suggests that the governance network of KVBR complements representative democracy. It deals mainly with “low politics”; the learning and policy directions are developed in the governance network, but the decisions are embedded in representative democratic structures. Because several organizations and agencies co-own the process and are committed to the outcomes, there is a shared or extended accountability. A recent large investment in KVBR caused a major crisis at the municipal level, fueled by the financial crisis. The higher levels of the governance network, however, served as a social memory and enhanced resilience of the present biosphere development trajectory. For self-organized networks, legitimacy is the bridge between adaptability and accountability; accountability is secured as long as the adaptive governance network performs well, i.e., is perceived as legitimate. Governing and ensuring accountability of governance networks, without hampering their flexibility, adaptability, and innovativeness, represents a new challenge for the modern state.
Journal Article
Estimating countries’ additional carbon accountability for closing the mitigation gap based on past and future emissions
Quantifying fair national shares of the remaining global carbon budget has proven challenging. Here, we propose an indicator—additional carbon accountability—that quantifies countries’ responsibility for mitigation and CO
2
removal in addition to achieving their own targets. Considering carbon debts since 1990 and future claims based on countries’ emission pathways, the indicator uses an equal cumulative per capita emissions approach to allocate accountability for closing the mitigation gap among countries with a positive total excessive carbon claim. The carbon budget is exceeded by 576 Gigatonnes of fossil CO
2
when limiting warming below 1.5 °C (50% probability). Additional carbon accountability is highest for the United States and China, and highest per capita for the United Arab Emirates and Russia. Assumptions on carbon debts strongly impact the results for most countries. The ability to pay for this accountability is challenging for Iran, Kazakhstan and several BRICS+ members, in contrast to the G7 members.
In addition to national climate targets, the authors estimate countries’ additional accountability to stay within the 1.5-degree carbon budget. They account for G7 countries having the highest carbon debts while several BRICS+ countries have high future claims.
Journal Article