Rats distinguish between absence of events and lack of evidence in contingency learning.

The goal of three experiments was to study whether rats are aware of the difference between absence of events and lack of evidence. We used a Pavlovian extinction paradigm in which lights consistently signaling sucrose were suddenly paired with the absence of sucrose. The crucial manipulation involved the absent outcomes in the extinction phase. Whereas in the Cover conditions, access to the drinking receptacle was blocked by a metal plate, in the No Cover conditions, the drinking receptacle was accessible. The Test phase showed that in the Cover conditions, the measured expectancies of sucrose were clearly at a higher level than in the No Cover conditions. We compare two competing theories potentially explaining the findings. A cognitive theory interprets the observed effect as evidence that the rats were able to understand that the cover blocked informational access to the outcome information, and therefore the changed learning input did not necessarily signify a change of the underlying contingency in the world. An alternative associationist account, renewal theory, might instead explain the relative sparing of extinction in the Cover condition as a consequence of context change. We discuss the merits of both theories as accounts of our data and conclude that the cognitive explanation is in this case preferred

Welcome to the Journal of Evolution and Health

Welcome to the first issue of the Journal of Evolution and Health! The Journal of Evolution and Health is the peer-reviewed, open-access journal of the Ancestral Health Society, a community of scientists, healthcare professionals, and laypersons who collaborate to understand health challenges from an evolutionary perspective

Optimized laser turrets for minimum phase distortion

An analysis and computer program which optimizes laser turret geometry to obtain minimum phase distortion is described. Phase distortion due to compressible, inviscid flow over small perturbation laser turrets in subsonic or supersonic flow is calculated. The turret shape is determined by a two dimensional Fourier series; in a similar manner, the flow properties are given by a Fourier series. Phase distortion is calcualted for propagation at serveral combinations of elevation and azimuth angles. A sum is formed from the set of values, and this sum becomes the objective function for an optimization computer program. The shape of the turret is varied to provide minimum phase distortion

Partitioning the power set of [n][n] into CkC_k-free parts

We show that for $n \geq 3, n\ne 5$, in any partition of $\mathcal{P}(n)$, the set of all subsets of $[n]=\{1,2,\dots,n\}$, into $2^{n-2}-1$ parts, some part must contain a triangle --- three different subsets $A,B,C\subseteq [n]$ such that $A\cap B$, $A\cap C$, and $B\cap C$ have distinct representatives. This is sharp, since by placing two complementary pairs of sets into each partition class, we have a partition into $2^{n-2}$ triangle-free parts. We also address a more general Ramsey-type problem: for a given graph $G$, find (estimate) $f(n,G)$, the smallest number of colors needed for a coloring of $\mathcal{P}(n)$, such that no color class contains a Berge-$G$ subhypergraph. We give an upper bound for $f(n,G)$ for any connected graph $G$ which is asymptotically sharp (for fixed $k$) when $G=C_k, P_k, S_k$, a cycle, path, or star with $k$ edges. Additional bounds are given for $G=C_4$ and $G=S_3$.Comment: 12 page

Inclusive or exclusive participation: Paradigmatic tensions in the mosaic approach and implications for childhood research

Caralyn Blaisdell - ORCID 0000-0002-5491-7346 https://orcid.org/0000-0002-5491-7346Early childhood research continues to be dominated by psychological research in the positivist paradigm. The Mosaic approach is one work that contests this dominant discourse on early childhood, using task-based, participatory inquiry to share power and involve children as co-constructors of knowledge. However, there are paradigmatic tensions underlying the use of task-based methods. In this paper I examine these tensions in the context of my own experience as an early career researcher. In particular the complex role of the researcher is discussed, and connected to issues of inclusion and exclusion regarding children’s participation in the research process.http://www.childhoodstoday.org/article.php?id=686pubpub

An Investigation into Capitalism and Unfree Labor in the Twenty-First Century

From the nineteenth century transatlantic slave trade to the contemporary era of mass incarceration, capitalism\u27s entanglement with unfree labor has been the subject of scholarly research from Karl Marx\u27s Capital, Vol I. (1867) to Eric Williams\u27 Capitalism and Slavery (1944) to Dennis Childs\u27 Slaves of the State (2015). However, with more people enslaved today than all of the people violently seized from Africa during the transatlantic slave trade (Bales, 2012, p. 9) and capitalism persisting as the predominant worldwide economic system, a critical analysis of the structural relationship between capitalism and unfree labor remains all too pertinent in the twenty-first century, especially if we as a society truly wish to abolish all modes of unfree labor. Hence, the purpose of this investigation into capitalism and unfree labor in the twenty-first century is to examine prevalent forms of unfree labor which exist in the present day capitalist mode of production, namely unfree prison labor, unfree migrant labor, and unfree international labor. The conclusion to this research suggests that the production and exploitation of unfree laborers is the result of a structural tendency inextricable to the framework of capitalism itself. With a werewolf hunger for surplus labor [ and maximizing surplus-value] (Marx, 1867, p. 291), capital in the twenty-first century continues to commandeer a panoply of state institutions and functions responsible for incarceration, immigration, and international trade in order to force the cost of labor back towards[ ... ] zero (Marx, 1867, p. 657)