The Growth and Decline of the Western Roman Empire: Quantifying the Dynamics of Army Size, Territory, and Coinage

We model the Western Roman Empire from 500 BCE to 500 CE, aiming to understand the interdependent dynamics of army size, conquered territory and the production and debasement of coins within the empire. The relationships are represented through feedback relationships and modelled mathematically via a dynamical system, specified as a set of ordinary differential equations. We analyze the stability of a subsystem and determine that it is neutrally stable. Based on this, we find that to prevent decline, the optimal policy was to stop debasement and reduce the army size and territory during the rule of Marcus Aurelius. Given the nature of the stability of the system and the kind of policies necessary to prevent decline, we argue that a high degree of centralized control was necessary, in line with basic tenets of structural-demographic theory. This article was updated on 01/09/2020 to correct an error in equation (3.5). Page numbers were updated on 01/05/2021

Individual strategies in the rat gambling task are related to voluntary alcohol intake, but not sexual behavior, and can be modulated by naltrexone

IntroductionGambling disorder (GD) is the first non-substance or behavioral addiction to be included in substance-related and addictive disorders in DSM-5. Since GD is a younger phenomenon relative to alcohol and substance use disorders, little is known about potential unique features in GD and to what extent characteristics are shared with alcohol and substance use disorders. The rat gambling task (rGT) is used to study decision-making in rats. This study aimed to identify individual differences in rGT strategies and explore the stability of these strategies over time. Moreover, motor impulsivity, sexual behavior, and voluntary alcohol intake were examined in rats with different rGT strategies. Finally, the response to naltrexone on performance in rats with different rGT strategies was investigated. MethodsMale Lister hooded rats (n = 40) underwent repeated testing in the rGT, repeated copulatory behavioral tests, and 7 weeks of voluntary alcohol intake through a modified intermittent two-bottle free-choice paradigm. Finally, rats were treated with naltrexone prior to testing in the rGT. ResultsThe results revealed individual choice strategies in the rGT that were stable over time, even after multiple interruptions and other behavioral testing. The rats with a risky choice strategy displayed higher motor impulsivity and voluntary alcohol intake than the other groups. No difference in sexual behavior was found between the different rGT groups. Finally, in all rats irrespectively of rGT strategy, treatment with naltrexone decreased the number of completed trials and premature responses, and increased omissions, which indicates an overall lowered motivation. DiscussionIn conclusion, rats with risky rGT strategies had higher voluntary alcohol intake but not elevated sexual behavior, indicating shared underlying mechanisms between rGT strategies and alcohol intake but not natural rewards in terms of sexual behavior. Finally, naltrexone treatment resulted in an overall lowered motivation in the rGT

Individual strategies in the rat gambling task are related to voluntary alcohol intake, but not sexual behavior, and can be modulated by naltrexone

IntroductionGambling disorder (GD) is the first non-substance or behavioral addiction to be included in substance-related and addictive disorders in DSM-5. Since GD is a younger phenomenon relative to alcohol and substance use disorders, little is known about potential unique features in GD and to what extent characteristics are shared with alcohol and substance use disorders. The rat gambling task (rGT) is used to study decision-making in rats. This study aimed to identify individual differences in rGT strategies and explore the stability of these strategies over time. Moreover, motor impulsivity, sexual behavior, and voluntary alcohol intake were examined in rats with different rGT strategies. Finally, the response to naltrexone on performance in rats with different rGT strategies was investigated.MethodsMale Lister hooded rats (n = 40) underwent repeated testing in the rGT, repeated copulatory behavioral tests, and 7 weeks of voluntary alcohol intake through a modified intermittent two-bottle free-choice paradigm. Finally, rats were treated with naltrexone prior to testing in the rGT.ResultsThe results revealed individual choice strategies in the rGT that were stable over time, even after multiple interruptions and other behavioral testing. The rats with a risky choice strategy displayed higher motor impulsivity and voluntary alcohol intake than the other groups. No difference in sexual behavior was found between the different rGT groups. Finally, in all rats irrespectively of rGT strategy, treatment with naltrexone decreased the number of completed trials and premature responses, and increased omissions, which indicates an overall lowered motivation.DiscussionIn conclusion, rats with risky rGT strategies had higher voluntary alcohol intake but not elevated sexual behavior, indicating shared underlying mechanisms between rGT strategies and alcohol intake but not natural rewards in terms of sexual behavior. Finally, naltrexone treatment resulted in an overall lowered motivation in the rGT

RNA packaging motor: From structure to quantum mechanical modelling and sequential-stochastic mechanism

The bacteriophages of the Cystoviridae family package their single stranded RNA genomic precursors into empty capsid (procapsids) using a hexameric packaging ATPase motor (P4). This molecular motor shares sequence and structural similarity with RecA-like hexameric helicases. A concerted structural, mutational and kinetic analysis helped to define the mechanical reaction coordinate, i.e. the conformational changes associated with RNA translocation. The results also allowed us to propose a possible scheme of coupling between ATP hydrolysis and translocation which requires the cooperative action of three consecutive subunits. Here, we first test this model by preparing hexamers with defined proportions of wild type and mutant subunits and measuring their activity. Then, we develop a stochastic kinetic model which accounts for the catalytic cooperativity of the P4 hexamer. Finally, we use the available structural information to construct a quantum-chemical model of the chemical reaction coordinate and obtain a detailed description of the electron density changes during ATP hydrolysis. The model explains the results of the mutational analyses and yields new insights into the role of several conserved residues within the ATP binding pocket. These hypotheses will guide future experimental work

Soil pollution assessment in the Baia Mare area after partial closure of ore processing activities

The paper presents the assessment of the soil pollution with Cu, Pb and Zn in the Baia Mare area, historically polluted with metals resulted from mining and processing of non-ferrous ores. Despite the closure of mines and reducing the activity related to ore processing, Baia Mare is still a highly polluted site with Pb, Cu and Zn. The Tessier extraction scheme carried out on soil samples recently collected revealed the residual fraction as dominant for all three metals, followed by the reducible fraction bound to Fe and Mn oxides. The exchangeable fraction, considered as the most mobile fraction and that bound to carbonates, which can be mobilized under acidic conditions, were lower. The presence of the oxidisable metal fraction was also observed

Activation of AMPK/Acetyl-Coa carboxylase in the hypothalamus of cold exposed rats

Orientadores: Marcio Alberto Torsoni, Licio Augusto Velloso.Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciencias MedicasResumo: A exposição de animais homeotérmicos ao frio leva a uma poderosa ativação da sinalização anorexigênica, acompanhada por resistência molecular e funcional à inibição da alimentação induzida pela insulina. Evidências recentes sugerem que a AMPK participa do controle da saciedade e da adiposidade, dependente de nutriente. O objetivo do presente estudo foi avaliar o efeito da exposição ao frio sobre a ativação molecular da sinalização da AMPK em hipotálamo de ratos. Immunoblotting demonstrou que a exposição ao frio por si é suficiente para induzir, em um modelo tempo dependente, a ativação molecular da serina/treonina quinase, proteína quinase ativada por AMP (AMPK) e a inativação da acetil-CoA carboxilase (ACC). Estes fenômenos moleculares foram acompanhados pela resistência à inativação da AMPK e pela ativação da ACC, dependentes de nutrientes. Além disso, a exposição ao frio levou a uma inibição parcial da resposta anorexigênica induzida pela alimentação, a qual foi acompanhada pela resistência à supressão da alimentação induzida pela insulina. Finalmente, a exposição ao frio prejudicou significativamente a inibição da AMPK, induzida pela insulina, através de um mecanismo dependente do ¿cross-talk¿ molecular entre fosfatidilinositol-3(PI3)-quinase/Akt e AMPK. Como conclusão, a hiperfagia durante a exposição ao frio resulta, pelo menos em parte, da resistência hipotalâmica à sinalização anorexigênica dependente de nutrientes e insulinaAbstract: The exposure of homeothermic animals to a cold environment leads to a powerful activation of orexigenic signalling which is accompanied by molecular and functional resistance to insulin-induced inhibition of feeding. Recent evidence suggests that AMPK participates in nutrient-dependent control of satiety and adiposity. The objective of the present study was to evaluate the effect of cold exposure upon the molecular activation of AMPK signalling in the hypothalamus of rats. Immunoblotting demonstrated that cold exposure per se is sufficient for inducing, on a time-dependent basis, the molecular activation of the serine/threonine kinase AMP-activated protein kinase (AMPK) and inactivation of the acetyl-CoA carboxylase (ACC). These molecular phenomena were accompanied by resistance to nutrient-induced inactivation of AMPK and activation of ACC. Moreover, cold-exposure led to a partial inhibition of a feeding-induced anorexigenic response, which was paralleled by resistance to insulin-induced suppression of feeding. Finally, cold exposure significantly impaired insulin-induced inhibition of AMPK through a mechanism dependent on the molecular cross-talk between phosphatidylinositol-3(PI3)-kinase/Akt and AMPK. In conclusion, increased feeding during cold exposure results, at least in part, from resistance to insulin¿ and nutrient-dependent anorexigenic signalling in the hypothalamusMestradoCiencias BasicasMestre em Clinica Medic

Behavioral profiling of SLC38A10 knockout mice using the multivariate concentric square field™ test

Introduction: SLC38A10 is a gene that encodes the SLC38A10 protein, also known as SNAT10. The SLC38 family is evolutionary old, and SLC38A10 is one of the oldest members of the family. It is ubiquitously expressed, and its substrates are glutamine, glutamate, alanine, aspartate, and serine. However, little is known about its biological importance.Methods: In the current study, an SLC38A10 knockout mouse was run in the multivariate concentric square fieldTM (MCSF) test. The MCSF test gives the mouse a choice of areas to explore; sheltered areas, elevated and illuminated areas, or open spaces, and a behavioral profile is obtained. The multivariate data obtained were analyzed (i) for each parameter, (ii) parameters grouped into functional categories, and (iii) with a principal component analysis.Results: In the trend analysis, knockout mice had a decreased exploratory behavior compared to controls but did not show a distinct grouping in the principal component analysis.Discussion: There was not a pronounced difference in the behavioral profile in SLC38A10 knockout mice compared to their wild-type controls, although subtle alterations in zones associated with exploratory behavior and risk assessment in female and male knockout mice, respectively, could be observed. These results imply that a loss of function of the SLC38A10 protein in mice does not drastically alter behavior in the MSCF test

Behavioral profiles of adolescent alcohol-preferring/non-preferring (P/NP) and high/low alcohol-drinking (HAD/LAD) rats are dependent on line but not sex

Initial contact with alcohol generally occurs during adolescence, and high consumption during this period is associated with increased risk for later alcohol (AUDs) and/or substance use disorders (SUDs). Rodents selectively bred for high or low alcohol consumption are used to identify behavioral characteristics associated with a propensity for high or low voluntary alcohol intake. The multivariate concentric square field (TM) (MCSF) is a behavioral test developed to study rodents in a semi-naturalistic setting. Testing in the MCSF creates a comprehensive behavioral profile in a single trial. The current aim was to examine the behavioral profiles of adolescent, bidirectionally selectively bred male and female high alcohol-consuming (P and HAD1/2) and low alcohol-consuming (NP and LAD1/2) rat lines, and outbred Wistar rats. Alcohol-naive rats were tested once in the MCSF at an age between postnatal days 30 and 35. No common behavioral profile was found for either high or low alcohol-consuming rat lines, and the effect of sex was small. The P/NP and HAD2/LAD2 lines showed within pair-dependent differences, while the HAD1/LAD1 lines were highly similar. The P rats displayed high activity and risk-associated behaviors, whereas HAD2 rats displayed low activity, high shelter-seeking behavior, and open area avoidance. The results from P rats parallel clinical findings that denser family history and risk-taking behavior are strong predictors of future AUDs, often with early onset. Contrarily, the HAD2 behavioral profile was similar to individuals experiencing negative emotionality, which also is associated with a vulnerability to develop, often with a later onset, AUDs and/or SUDs

Open field behavior in the house cricket (Acheta domesticus): effect of illumination, sex differences and individual consistency

Edible insects are worldwide promoted as an alternative protein, trace mineral and lipid source in animal feed and human food. The house cricket (Acheta domesticus) is already being reared at an industrial scale, yet current mass-rearing practices and facility design may still leave room for improvement. Behavioral tests have been suggested as an important assessment tool at the whole-organism level that can be used to find optimal housing conditions (e.g. density, diet, temperature). Here, we adapt the widely used open field test to the house cricket. We tested 16 male and 16 female house crickets four times under two different light intensities. Videos were analysed with Ethovision™ tracking software and variables distance moved, velocity, and duration and frequency in zone were extracted. Results showed that house crickets, like vertebrate model species, spent most time close to the walls of the arena, and crossed the center zone with high velocity. Brighter illumination was associated with increased velocity, in particular in the center zone during the first test occasion, suggesting avoidance of this zone. Male crickets had higher locomotory activity than females. Consistency repeatabilities and intraclass correlation coefficients (ICCs) were moderate to high, and the correlation between subsequent occasions became stronger over the four occasions at day 1, 2, 3 and 7. The first test occasion differed from subsequent occasions, therefore repeated testing may be necessary when analysing experimental manipulations of small effect size. Overall, the results are promising for use of the open field test as a precise phenotyping tool