The concept of an ecological niche (econiche) has been used in a variety of ways, some of which are incompatible with a relational or functional interpretation of the term. This essay seeks to standardize usage by limiting the concept to functional relations between organisms and their surroundings, and to revise the concept to include epistemic relations. For most organisms, epistemics are a vital aspect of their functional relationships to their surroundings and, hence, a major determinant of their econiche. Rejecting the (...) traditional dualism of organism and environment, an econiche is defined as the reciprocal (dual) of a functionally specified class of organisms (FSTU). From this perspective, an econiche necessarily implies a certain type of organism, and a class of functionally similar organisms implies a special econiche.The econiche concept is also discussed in relation to other ecological terms that reflect the distributional patterns of organisms, such as habitat, and the concept of an empty niche is criticized. (shrink)

This article examines some of the main tenets of competition theory in light of the theory of evolution and the concept of an ecological niche. The principle of competitive exclusion and the related assumption that communities exist at competitive equilibrium - fundamental parts of many competition theories and models - may be violated if non-equilibrium conditions exist in natural communities or are incorporated into competition models. Furthermore, these two basic tenets of competition theory are not compatible with the theory of (...) evolution. Variation in ecologically significant environmental factors and non-equilibrium in population numbers should occur in most natural communities, and such changes have important effects on community relations, niche overlap, and the evolution of ecosystems. Ecologists should view competition as a process occurring within a complexdynamic system, and should be wary of theoretical positions built upon simple laboratory experiments or simplistic mathematical models.In considering the relationship between niche overlap and competition, niche overlap should not be taken as a sufficient condition for competition; many factors may prevent or diminish competition between populations with similar resource utilization patterns. The typically opposing forces of intraspecific and interspecific competition need to be simultaneously considered, for it is the balance between them that in large part determines niche boundaries. (shrink)

Food sharing may be used for mate attraction, sexual access, or mate retention in humans, as in many other species. Adult humans tend to perceive more intimacy in a couple if feeding is observed, but the increased perceived intimacy may be due to resource provisioning rather than feeding per se. To address this issue, 210 university students (66 male) watched five short videos, each showing a different mixed-sex pair of adults dining together and including feeding or simple provisioning or no (...) food sharing. A survey concerning attraction and intimacy in the dyad was completed after each video. Both provisioning and feeding produced higher ratings of “Involvement,” with feeding producing the highest ratings. Similarly, the perceived attraction of each actor to the other was lowest when no food sharing was shown and highest when feeding was displayed. These findings are consistent with a view of feeding as a courtship display in humans. (shrink)

Several suggestions are made for revision of Strategic Pluralism Theory (SPT). One revision requires recognition of the impact of individual differences in cognitive and behavioral competence on optimal mating strategy. In addition, SPT may need to incorporate certain self-regulatory processes such as the impact of widespread valuation of mates with one trait on their availability.

The phase φ of any wave is determined by the ratio x/λ consisting of the distance x propagated by the wave and its wavelength λ. Hence, the dependence of φ on λ constitutes an analogue system for the mathematical operation of division, that is to obtain the hyperbolic function f(ξ)≡1/ξ. We take advantage of this observation to decompose integers into primes and implement this approach towards factorization of numbers in a multi-path Michelson interferometer. This work is part of a larger (...) program geared towards unraveling the connections between quantum mechanics and number theory. We briefly summarize this aspect. (shrink)

‘Tympaniser’, Alan Bass tells us, is an ‘archaic verb meaning to ridicule publicly’ or to decry. In the essay fronting Margins of Philosophy called ‘Tympan’ Derrida decries the philosophy that would own its limits, absorbing ‘the margin of its own volume’. While it is Derrida’s late work on the ‘animal question’ that has brought his insistence on the nourishment of the limits between species as limitrophy to wider attention, it is also named as the general condition of the interface of (...) the limits in the much earlier text, ‘Tympan.’ There, in dislocating the tympanum, the margins of philosophy are eaten. Equally, given the rhythmic address of the tympanum, we might say that the margins of philosophy are beaten. Struggling within the strictures of a small town amateur dramatic rehearsal, Selma, the lead protagonist in Dancer in the Dark, makes a plea for more rhythm. But there is no license for tap-dancing in The Sound of Music. This chapter considers Dancer’s persistent play on rhythmic sounds as that which trip Selma’s fantasy song and dance numbers as a ‘tympanising’ of the limits, notably of the limits of the law in both juridical and symbolic senses, as they also work the edges of the film’s two styles. In a provocative analysis of this film, Cary Wolfe suggests that we might understand Selma’s vocal style as a refusal of the phallic imposition of language, and that her virtually suicidal submission to the death sentence construed as a Lacanian ‘feminine’ act, allow for a notion of a ‘posthuman feminine’. ‘Tympan Alley’ redirects Wolfe’s tantalising term ‘posthuman feminine’ through a more consistently Derridean line of thought. It draws on Derrida’s late work on the animal, in which it is polemically clear that deconstruction has never been confined to the signifier nor to the human, and sounds out the implications of his early work on b/eating the limits through Selma’s percussive ear. (shrink)

Contemporary philosophical work on causation is a tangled mess of disparate aims, approaches, and accounts. Best to cut through it by means of ruthless but, hopefully, sensible judgments. The ones that follow are designed to sketch the most fruitful avenues for future work.

A poset is well‐partially ordered (WPO) if all its linear extensions are well orders; the supremum of ordered types of these linear extensions is the length, of p. We prove that if the vertex set X is infinite, of cardinality κ, and the ordering ⩽ is the intersection of finitely many well partial orderings of X,, then, letting, with, denote the euclidian division by κ (seen as an initial ordinal) of the length of each corresponding poset: where denotes (...) the least initial ordinal greater than the ordinal. This inequality is optimal. This result answers questions of Forster. (shrink)

Given i, j, k ∈ {1,2,3,4}, the notion of -length neutrosophic subalgebras in BCK=BCI-algebras is introduced, and their properties are investigated. Characterizations of length neutrosophic subalgebras are discussed by using level sets of interval neutrosophic sets. Conditions for level sets of interval neutrosophic sets to be subalgebras are provided.

In lieu of an abstract, here is a brief excerpt of the content:134 Feminist Studies 41, no. 1. © 2015 by Gabeba Baderoon Focal Length Gabeba Baderoon I take out the black and white photos I brought with me from Cape Town and haven’t looked at for years and stand them next to one another on the dining room table. In one, my mother in her white coat at the hospital looks up from her notes, distracted, in the grainy (...) matte finish you could ask for in the eighties instead of gloss. Here she is, younger, standing by the window, holding the telephone with its spiraling black cord to her ear, the curtain slanting to the side as she turns away from the camera. I take down from the wall the framed collection of Rafi’s baby photos I’d found wrapped in tissue paper among the tablecloths in the sideboard we inherited from his parents and line us up with each other. There he is, his face fitting into his mother’s shoulder; his brother holding him with hands under the armpits the way he was told; posing by a white door in a hooded woolen coat, his head reaching just above the handle. When I unwrapped them, the tissue paper had only one set of creases, untouched since she packed them for their long journey. In the soft focus of faded paper, I am standing with my back to a VW Beetle I know is pale green, my hands tucked behind me against the bumper, the license plate showing the number from the time before we moved from Uitenhage to Cape Town. In this one, I am on my mother’s lap, leaning against her like gravity. In the photo the focus shifts between my face and my mother’s. She is looking at me, like my father who is taking the picture. My face is clear and hers slightly blurred, as though his eyes are moving between us, as though the camera cannot capture the eye’s oscillation between two people one loves at the same time. One photo had been folded into three, bent once and then again to fit into a pocket, close enough to the skin to warm the paper, and then smoothed out again to fit into a frame. In it, I am turning sideways toward the camera—someone must have called my name—and a line creases just Gabeba Baderoon 135 beneath my eyes. Folded, hidden, forgotten, memory doesn’t come to me straight. The pleat of the curtain as she leans against it, his face in the crook of her shoulder as though he would never leave, me turning toward my name, the paper keeping its original crease. Poetry for Beginners In the evening poetry class for beginners in the community hall during the introductions a girl looking down behind her hair and a thick brown coat she doesn’t take off breathes in deep and risking something says fast my boyfriend’s in prison and I’m here to find out how to write to him through the bars and someone laughs and she pulls herself back into her coat and from inside looks past us and the next week doesn’t come back and I think of her for years and what poetry is I think of her long pause at the beginning her silence before and her silence after and I think this is my origin where poetry is risk, is betrayal and the memory of the first question how not to be alone 136 Gabeba Baderoon ID Photos In the small caravan parked permanently next to the Traffic Department with the handwritten sign ID Photos Taken Here its wheels rusted into place the young old photographer with dreadlocks and a tired poet’s face is shaking his head from side to side muttering some version of no just before me a woman in a long black skirt and black veil unties the loop of fabric knotted behind her head and her face briefly emerges the young old photographer sees everything hundreds of unclaimed photos line the inside of his caravan the making of identity interrupted and turned into small sad signs of something else we don’t look at... (shrink)

Internet Alley is much more a book about regional history than about politics, economics, or history of technology, yet it draws extensively on all of these fields. The book is stronger for its interdisciplinarity, but as a result does not sit comfortably within any traditional historical discourse. Historians of science or technology not dealing with northern Virginia in the twentieth century will find little of help in this book.

I discuss a rarely mentioned correspondence between Einstein and Swann on the constructive approach to the special theory of relativity, in which Einstein points out that the attempts to construct a dynamical explanation of relativistic kinematical effects require postulating a fundamental length scale in the level of the dynamics. I use this correspondence to shed light on several issues under dispute in current philosophy of spacetime that were highlighted recently in Harvey Brown’s monograph Physical Relativity, namely, Einstein’s view on (...) the distinction between principle and constructive theories, and the consequences of pursuing the constructive approach in the context of spacetime theories. r 2008 Elsevier Ltd. All rights reserved. (shrink)

In this paper we examine to what extent the lengths of the links in an animated articulated figure can be changed without the viewer being aware of the change. This is investigated in terms of a framework that emphasizes the role of attention in visual perception. We conducted a set of five experiments to establish bounds for the sen-sitivity to changes in length as a function of several parameters and the amount of attention available. We found that while (...) class='Hi'>length changes of 3% can be perceived when the relevant links are given full attention, changes of over 20% can go unnoticed when attention is not focused in this way. These results provide general guidelines for algorithms that produce or process character motion data and also bring to light some of the potential gains that stand to be achieved with attention-based algorithms. (shrink)

Telomeres are short repetitive DNA sequences capping the ends of chromosomes. Telomere shortening occurs during cell division and may be accelerated by oxidative damage or ameliorated by telomere maintenance mechanisms. Consequently, telomere length changes with age, which was recently confirmed in a large meta‐analysis across vertebrates. However, based on the correlation between telomere length and age, it was concluded that telomere length can be used as a tool for chronological age estimation in animals. Correlation should not be (...) confused with predictability, and the current data and studies suggest that telomeres cannot be used to reliably predict individual chronological age. There are biological reasons for why there is large individual variation in telomere dynamics, which is mainly due to high susceptibility to a wide range of environmental, but also genetic factors, rendering telomeres unfeasible as a tool for age estimation. The use of telomeres for chronological age estimation is largely a misguided effort, but its occasional reappearance in the literature raises concerns that it will mislead resources in wildlife conservation. (shrink)

The time-limits imposed by the κλεψύδρα on speakers in Athenian trials have been much discussed, but a valuable distillation of the ancient evidence and modern interpretations of it has recently been made by P. J. Rhodes, A Commentary on the Aristotelian Athenaion Politeia , pp. 719–28. He prudently states his own conclusions in a cautious manner, but I find them convincing. One khous of water took 3 minutes to run out; this is indicated by the length of time taken (...) by the κλεψύδρα found in the Agora , which holds 2 khoes and takes 6 minutes, and it is also consistent with the evidence of Aiskhines about the διαμεμετρημένη μέρα. In a ‘measured-through day’, used only for public cases, the total amount of time allowed for the speeches in a trial was 11 amphoreis , equivalent to 132 khoes, taking 396 minutes; one third of this time was allocated to the prosecution, one third to the defence, and one third to the speeches on the assessment of the penalty . Time taken for other proceedings, including the allocation of jurors to courts, voting, and payment of jurors at the end of the day , was additional. (shrink)

Loop quantum gravity predicts that spatial geometry is fundamentally discrete. Whether this discreteness entails a departure from exact Lorentz symmetry is a matter of dispute that has generated an interesting methodological dilemma. On one hand one would like the theory to agree with current experiments, but, so far, tests in the highest energies we can manage show no such sign of departure. On the other hand one would like the theory to yield testable predictions, and deformations of exact Lorentz symmetry (...) in certain yet– to–be–tested regimes may have phenomenological consequences. Exposing their shortcomings, here I discuss two arguments that exemplify this dilemma, and compare them to other cases from the history of physics that share their symptoms. (shrink)

Assume $\mathsf {ZF} + \mathsf {AD}$ and all sets of reals are Suslin. Let $\Gamma $ be a pointclass closed under $\wedge $, $\vee $, $\forall ^{\mathbb {R}}$, continuous substitution, and has the scale property. Let $\kappa = \delta (\Gamma )$ be the supremum of the length of prewellorderings on $\mathbb {R}$ which belong to $\Delta = \Gamma \cap \check \Gamma $. Let $\mathsf {club}$ denote the collection of club subsets of $\kappa $. Then the countable length everywhere (...) club uniformization holds for $\kappa $ : For every relation $R \subseteq {}^{<{\omega _1}}\kappa \times \mathsf {club}$ with the property that for all $\ell \in {}^{<{\omega _1}}\kappa $ and clubs $C \subseteq D \subseteq \kappa $, $R(\ell,D)$ implies $R(\ell,C)$, there is a uniformization function $\Lambda : \mathrm {dom}(R) \rightarrow \mathsf {club}$ with the property that for all $\ell \in \mathrm {dom}(R)$, $R(\ell,\Lambda (\ell ))$. In particular, under these assumptions, for all $n \in \omega $, $\boldsymbol {\delta }^1_{2n + 1}$ satisfies the countable length everywhere club uniformization. (shrink)