Lowest-unique sealed-bid auctions are auctions with endogenous participation, costly bids, and the lowest bid among all unique bids wins. Properties of symmetric NEs are studied. The symmetric NE with the lowest expected gains is the maximin outcome under symmetric strategies, and it is the solution to a mathematical program. Comparative statics for the number of bidders, the value of the item and the bidding cost are derived. The two bidders’ auction is equivalent to the Hawk–Dove game. Simulations of replicator (...) dynamics provide numerical evidence that the symmetric NE with the lowest expected gains is also asymptotically stable. (shrink)

In this paper, we study the auction to allocate an indivisible good when each potential buyer has a private and independent valuation for the item and suffers a negative externality if a competitor acquires it. In that case, the outside option of each buyer is mechanism-dependent, which implies that participation is endogenous. As several works in the literature have shown, the optimal auction entails strong threats to induce full entry and maximal expected revenue. This results from the full (...) commitment assumption, which ensures that threats are credible. We show that absent credible threats, the entry process does not lead to full participation: the equilibrium entails screening of agents in the entry stage and a trade-off between reserve prices and entry fees. Besides, we discuss the conditions under which the impossibility to use threats does not prevent the seller from ensuring a minimal screening and reaching a high expected revenue. (shrink)

Lowest-unique sealed-bid auctions are auctions with endogenous participation, costly bids, and the lowest bid among all unique bids wins. Properties of symmetric NEs are studied. The symmetric NE with the lowest expected gains is the maximin outcome under symmetric strategies, and it is the solution to a mathematical program. Comparative statics for the number of bidders, the value of the item and the bidding cost are derived. The two bidders’ auction is equivalent to the Hawk–Dove game. Simulations of replicator (...) dynamics provide numerical evidence that the symmetric NE with the lowest expected gains is also asymptotically stable. (shrink)

This article further studies ex ante efficient auctions in the setting of Stegeman (1996 Participation costs and efficient auctions, Journal of Economic Theory 71, 228–259.), where there exist entry costs for bidders who know their valuations. An alternative method is established to address efficient auctions. This method illustrates the intuition why the ex ante efficient allocation is Bayesian implementable through the Stegeman (1996) auction (a second-price auction with a reserve price equal to seller’s valuation and no entry fee). (...) More importantly, our method leads to an alternative ex ante efficient auction that implements uniquely the efficient entry. Thus, this alternative auction solves the entry indeterminacy problem of the Stegeman (1996) auction, which generally induces inefficient entry equilibria besides the efficient ones. (shrink)

This paper presents a new theoretical justification for the Cournot–Bertrand model to arise in equilibrium when firms have, at the outset, the same cost structure and sell symmetrically differentiated products. The Cournot–Bertrand model assumes some firms compete on price, adjusting their production to meet demand, while others set quantities and let their price adjust until market equilibrium is reached. We show that this may occur endogenously due to the possibility of entry, which may be deterred when some of the (...) incumbents decide to set prices, while others free ride on this behavior and choose quantities. (shrink)

The law of prior entry was one of E.B. Titchener’s seven fundamental laws of attention. According to Titchener : “the object of attention comes to consciousness more quickly than the objects which we are not attending to.” Although researchers have been studying prior entry for more than a century now, progress in understanding the effect has been hindered by the many methodological confounds present in early research. As a consequence, it is unclear whether the behavioral effects reported in (...) the majority of published studies in this area should be attributed to attention, decisional response biases, and/or, in the case of exogenous spatial cuing studies of the prior-entry effect, to sensory facilitation effects instead. In this article, the literature on the prior-entry effect is reviewed, the confounds present in previous research highlighted, current consensus summarized, and some of the key questions for future research outlined. In particular, recent research has now provided compelling psychophysical and electrophysiological evidence to support the claim that attending to a sensory modality, spatial location, or stimulus feature/attribute can all give rise to a relative speeding-up of the time of arrival of attended, as compared to relatively less attended stimuli. Prior-entry effects have now been demonstrated following both the endogenous and exogenous orienting of attention, though prior-entry effects tend to be smaller in magnitude when assessed by means of participants’ performance on SJ tasks than when assessed by means of their performance on TOJ tasks. (shrink)

ABSTRACT The list of proposed addictions has recently grown to include television, videogames, shopping, day trading, kleptomania, and use of the Internet. These activities share with a more established entry, gambling, the property that they require no delivery of a biological stimulus that might be thought to unlock a hardwired brain process. I propose a framework for analyzing that class of incentives that do not depend on the prediction of physically privileged environmental events: people have a great capacity to (...) coin endogenous reward; we learn to cultivate it, and, where it is entrapping, to minimize it, by managing internally generated appetites for it. The basic method of cultivating endogenous reward is to learn cues that predict when best to harvest the reward that has been made possible by the growth of these appetites. This hedonic management occurs in the same motivational marketplace as the instrumental planning that seeks environmental goods in the conventional manner, and presumably obeys the same laws of temporal difference learning; but these laws are no longer limiting. Furthermore, instrumental contingencies often provide the most productive structure for hedonic management as well, for reasons that I discuss; but the needs of hedonic management create incentives both to pursue instrumental goals in a suboptimal manner and to avoid noticing how the hedonic incentive affects this pursuit. The result is the apparent irrationality that is often observed in process addictions. (shrink)

Viruses are the simplest of pathogens, but possess sophisticated molecular mechanisms to manipulate host behavior, frequently utilizing molecular mimicry. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been shown to bind to the host receptor neuropilin-1 in order to gain entry into the cell. To do this, the virus utilizes its spike protein polybasic cleavage site (PCS), which mimics the CendR motif of neuropilin-1’s endogenous ligands. In addition to facilitating cell entry, binding to neuropilin-1 has analgesic effects. (...) We discuss the potential impact of neuropilin-1 binding by SARS-CoV-2 in ameliorating sickness behavior of the host, and identify a convergent evolutionary strategy of PCS cleavage and subsequent neuropilin binding in other human viruses. In addition, we discuss the evolutionary leap of the ancestor of SARS-COV-2, which involved acquisition of the PCS thus faciliting binding to the neuropilin-1 receptor. Acquisition of the PCS by the ancestor of SARS-CoV-2 appears to have led to pleiotropic beneficial effects including enhancement of cell entry via binding to ACE2, facilitation of cell entry via binding to neuropilin-1, promotion of analgesia, and potentially the formation of decoy epitopes via enhanced shedding of the S1 subunit. Lastly, other potential neuromanipulation strategies employed by SARS-CoV-2 are discussed, including interferon suppression and the resulting reduction in sickness behavior, enhanced transmission through neurally mediated cough induction, and reduction in sense of smell. (shrink)

The extended dual-aspect monism framework of consciousness, based on neuroscience, consists of five components: (1) dual-aspect primal entities; (2) neural-Darwinism: co-evolution and co-development of subjective experiences (SEs) and associated neural-nets from the mental aspect (that carries the SEs/proto-experiences (PEs) in superposed and unexpressed form) and the material aspect (mass, charge, spin and space-time) of fundamental entities (elementary particles), respectively and co-tuning via sensorimotor interaction; (3) matching and selection processes: interaction of two modes, namely, (a) the non-tilde mode that is the (...) material and mental aspect of cognition (memory and attention) related feedback signals in a neural-network, which is the cognitive nearest past approaching towards present; and (b) the tilde mode that is the material and mental aspect of the feed forward signals due to external environmental input and internal endogenous input, which is the nearest future approaching towards present and is a entropy-reversed representation of non-tilde mode; (4) the segregation and integration of information, and (5) the necessary ingredients of SEs (such as wakefulness, attention, re-entry, working memory, stimulus at or above threshold level, and neural-net PEs). This framework leads to structural and functional coherence between the mind and the brain, bridges the explanatory gap (the gap between SEs and their neural-correlates), and leads to our mundane subjective experiences. This extended dual-aspect monism (eDAM) framework (Vimal, 2008, 2010, 2013, 2015a, 2015b) could be the fundamental basis of various religions and philosophies. This is a Western perspective. On the other hand, Eastern perspectives emphasize the practical methods for achieving altered experience at samadhi state. An important corollary of these methods (such as yogic method) is the sublimation of negative aspects of seven groups of self-protective energy system (desire, anger, ego, greed, attachment, jealousy, and selfish-love) into their positive aspects. Their negative aspects create war and suffering, whereas their positive aspects advance science and technology, family values, peace, and happiness. Here, the Western perspective framework is extended to include the concepts of the sublimation process to encompass Eastern perspectives. The four elements (war, suffering, peace, and happiness) are ubiquitous in both space and time because they are essential contributors to the variations for natural selection in our evolutionary system. The sublimation process optimizes the system: minimizes war and suffering, maximizes peace and happiness, and enhances family values and individual progress. This is consistent with both Eastern and Western perspectives. (shrink)

Endogenous retrovirsuses (ERVs) have long been known to influence gene expression in plants in important ways, but what of their roles in mammals? Our relatively sparse knowledge in that area was recently increased with the finding that ERVs can influence the expression of mammalian resident genes by disrupting transcriptional termination. For many mammalian biologists, retrotransposition is considered unimportant except when it disrupts the reading frame of a gene, but this view continues to be challenged. It has been known for (...) some time that integration into an intron can create novel transcripts and integration upstream of a gene can alter the expression of the transcript, in many cases producing phenotypic consequences and disease. The new findings on transcriptional termination extend the opportunities for retrotransposons to play a role in human disease. (shrink)

La plupart des projets d’architectures cognitives dans les sciences cognitives et des explications des processus cérébraux dans les neurosciences interprètent l’esprit/cerveau comme réactif : le processus est déclenché par un stimulus et se termine par une réponse. Mais il y a de plus en plus de données laissant penser que le cerveau est endogéniquement actif : des oscillations de l’activité électrochimique à de multiples fréquences ont lieu dans le cerveau même en l’absence de stimuli et ceux-ci servent plutôt à moduler (...) ces oscillations qu’à déclencher l’activité. De plus, des données montrent que cette activité endogène est utilisée dans diverses activités de traitement de l’information. Je m’appuie sur les données issues des enregistrements cellulaires unitaires, de l’EEG et de l’IRMf en situation passive, afin de soutenir la thèse d’un comportement oscillatoire continu dans le cerveau et d’identifier plusieurs manières dont ce comportement peut contribuer à la cognition. Si les sciences cognitives ont pour but de comprendre comment nous effectuons des tâches cognitives, elles ont besoin de développer des architectures cognitives qui intègrent le type d’activité endogène dynamique présentée par le cerveau. (shrink)

La plupart des projets d’architectures cognitives dans les sciences cognitives et des explications des processus cérébraux dans les neurosciences interprètent l’esprit/cerveau comme réactif : le processus est déclenché par un stimulus et se termine par une réponse. Mais il y a de plus en plus de données laissant penser que le cerveau est endogéniquement actif : des oscillations de l’activité électrochimique à de multiples fréquences ont lieu dans le cerveau même en l’absence de stimuli et ceux-ci servent plutôt à moduler (...) ces oscillations qu’à déclencher l’activité. De plus, des données montrent que cette activité endogène est utilisée dans diverses activités de traitement de l’information. Je m’appuie sur les données issues des enregistrements cellulaires unitaires, de l’EEG et de l’IRMf en situation passive, afin de soutenir la thèse d’un comportement oscillatoire continu dans le cerveau et d’identifier plusieurs manières dont ce comportement peut contribuer à la cognition. Si les sciences cognitives ont pour but de comprendre comment nous effectuons des tâches cognitives, elles ont besoin de développer des architectures cognitives qui intègrent le type d’activité endogène dynamique présentée par le cerveau. (shrink)

Why do people who disagree about one subject tend to disagree about other subjects as well? In this paper, we introduce a model to explore this phenomenon of ‘epistemic factionization’. Agents attempt to discover the truth about multiple propositions by testing the world and sharing evidence gathered. But agents tend to mistrust evidence shared by those who do not hold similar beliefs. This mistrust leads to the endogenous emergence of factions of agents with multiple, highly correlated, polarized beliefs.

This paper develops a mechanistic account of basic mental agency by identifying similarities between two of its major exemplars: endogenous attention and imagination. Five key similarities are identified: i) that both capacities are driven by currently prioritised goals that are either person-level or apt to become person-level. ii) that both deliver their outputs to the working memory iii) that both range across all and only conceptual contents; iv) that both proceed under the guidance of norms and/or habits; and v) (...) that both directly activate rather than inhibit content. These five features are consolidated by proposing that basic mental agency is essentially the power to call for conceptual content and hold it within our working memories. (shrink)

We contrast reactive and endogenously active perspectives on brain activity. Both have been pursued continuously in neurophysiology laboratories since the early 20thcentury, but the endogenous perspective has received relatively little attention until recently. One of the many successes of the reactive perspective was the identification, in the second half of the 20th century, of the distinctive contributions of different brain regions involved in visual processing. The recent prominence of the endogenous perspective is due to new findings of ongoing (...) oscillatory activity in the brain at a wide range of time scales, exploiting such techniques as single-cell recording, EEG, and fMRI. We recount some of the evidence pointing to ways in which this endogenous activity is relevant to cognition and behavior. Our major objective is to consider certain implications of the contrast between the reactive and endogenous perspectives. In particular, we relate these perspectives to two different characterizations of explanation in the new mechanistic philosophy of science. In a basic mechanistic explanation, the operations of a mechanism are characterized qualitatively and as functioning sequentially until a terminating condition is realized. In contrast, a dynamic mechanistic explanation allows for non-sequential organization and emphasizes quantitative modeling of the mechanisms's behavior. For example, with appropriate parameter values a set of differential equations can be used to demonstrate ongoing oscillations in a system organized with feedback loops. We conclude that the basic conception of mechanistic explanation is adequate for reactive accounts of brain activity, but dynamical accounts are required to explain sustained, endogenous activity. (shrink)

This paper examines the theoretical background and actual behavior in a gaming tournament with endogenous timing where a person has more incentive, structure, and time to form a strategy. The baseline treatment suggests that subgame perfection is a reasonable predictor of behavior –- subjects made 170 of 208 theoretically predicted choices of best actions, with the majority of mistakes made in timing choices by the players who did not survive the cut to the second round. Four sensitivity treatments established (...) that the design feature that lead to more predictable behavior was time to think –- 745 of 960 correctly predicted decisions with more time versus 595 of 960 with less time. A random effects Probit model suggests that the key design feature that closed the gap between predicted and observed behavior was not necessarily the non-linear payoffs created by the tournament design, but rather that the key was providing people with more time to think about their strategy. (shrink)

Uncovering the wealth of traditional African knowledge and techniques has direct implications for the future development of the continent. This book is written against the background of the tragedy that most Africans are profoundly ignorant of the achievements of the past, let alone the traditions that are still upheld today. It is an exploration and analysis of Africa's historical roots, and the editor is one of Africa's most distinguished philosophers. Rich in detailed and original field research, the volume covers a (...) wide variety of topics, from the probability theory of cowry shell diviners, to hydrology and rainmaking, and the links between sorcery and psychosomatic medicine. Chapters include the use of number systems, ingredients used in pharmaceutical practice, and the mysterious phenomena of foreign objects projected into human bodies. (shrink)

This paper studies a sender-receiver game in which both players want the receiver to choose the state-optimal action. Before observing the state, the sender observes a “contextual signal,” a payoff-irrelevant signal that correlates with states and is imperfectly shared with the receiver. Once the sender observes the state, the sender sends a message to the receiver, incurring a small messaging cost. It is shown that there is no miscommunication in any efficient equilibrium if the messaging cost is uniform or contextual (...) information is poorly shared between players. However, if the messaging costs are different between some messages, and contextual information can affect the probability ranking of states and is shared reasonably well, any efficient equilibrium that favors the sender exhibits miscommunication. Furthermore, the messages that cause miscommunication can be coarse or ambiguous, depending on how well players share contextual information. (shrink)

Evolutionary biology is striking for its ability to explain a large and diverse range of empirical phenomena on the basis of a few general theoretical principles. This article offers a philosophical perspective on the way that evolutionary biology has come to achieve such impressive generality, by focusing on “the strategy of endogenization”. This strategy involves devising evolutionary explanations for biological features that were originally part of the background conditions, or scaffolding, against which such explanations take place. Where successful, the strategy (...) moves biology a step closer to the ideal of explaining as much as possible from evolutionary first principles. The strategy of endogenization is illustrated through a series of biological examples, historical and recent, and its philosophical implications are explored. (shrink)

Does the desirability of social institutions for public goods provision depend on the extent to which they include mechanisms for endogenous enforcement of cooperative behavior? We consider alternative institutions that vary the use of direct punishments to promote social cooperation. In one institution, subjects participate in a public goods experiment in which an initial stage of voluntary contribution is followed by a second stage of voluntary, costly sanctioning. Another institution consists of the voluntary contribution stage only, with no subsequent (...) opportunity to sanction. In a third stage subjects vote for which institution they prefer for future interactions: do they prefer one that does allow sanctions or one that does not allow sanctions? Our results show that even though sanctions are frequently used when available, the clear majority of individuals vote for the institution that does not allow sanctions. Thus, a distinction is required between the principles that guide the choice of institutions and the principles that apply to actions guided by institutions. Our results indicate that it is the wealth generated by the institution that determines its desirability. (shrink)

In addition to endogenously produced opiates, which are part of normal affiliative neurocircuitry and attachment formation, exogenous opiates – such as drugs of addiction and abuse – may affect affiliation. We consider possible modulatory effects of such exogenous opiates on the development of early parent–infant attachment from both parents' and infants' perspectives.

Following much work in linguistic theory, it is hypothesized that the language faculty has a modular structure and consists of two basic components, a lexicon of (structured) entries and a computational system of combinatorial operations to form larger linguistic expressions from lexical entries. This target article provides evidence for the dual nature of the language faculty by describing recent results of a multidisciplinary investigation of German inflection. We have examined: (1) its linguistic representation, focussing on noun plurals and verb inflection (...) (participles), (2) processes involved in the way adults produce and comprehend inflected words, (3) brain potentials generated during the processing of inflected words, and (4) the way children acquire and use inflection. It will be shown that the evidence from all these sources converges and supports the distinction between lexical entries and combinatorial operations. (shrink)

The goal of this study is to characterize observers’ abilities to discriminate between endogenous and exogenous changes. To do so, we developed a new experimental paradigm. On each trial, participants were shown a dot pattern on the screen. Next, the pattern disappeared and participants were to reproduce it. Changes were surreptuously introduced in the stimulus, either by presenting participants anew with the dot pattern they had themselves produced on the previous trial or by presenting participants with a slightly different (...) dot pattern . We analyzed awareness of the changes and behavioral adaptation to them in a dynamical manner. We observe signal attenuation in the presence of endogenous change, dissociation between self-attribution reports and behavioral effect of agency. We discuss the source of this sensitive attenuation as well as the relation between a minimal or core self and an extended, narrative or autobiographical self. (shrink)

This paper examines the theoretical background and actual behavior in a gaming tournament with endogenous timing where a person has more incentive, structure, and time to form a strategy. The baseline treatment suggests that subgame perfection is a reasonable predictor of behavior –- subjects made 170 of 208 theoretically predicted choices of best actions, with the majority of mistakes made in timing choices by the players who did not survive the cut to the second round. Four sensitivity treatments established (...) that the design feature that lead to more predictable behavior was time to think –- 745 of 960 correctly predicted decisions with more time versus 595 of 960 with less time. A random effects Probit model suggests that the key design feature that closed the gap between predicted and observed behavior was not necessarily the non-linear payoffs created by the tournament design, but rather that the key was providing people with more time to think about their strategy. (shrink)

Several studies have revealed the presence in human DNA of thousands of endogenous retrovirus genomes, or HERVs. Many HERVs are related to extant retroviruses that infect other vertebrates and some have been present in the germ line of primates for millions of years. Although the HERVs that have been isolated are defective and thus do not encode infectious retroviruses, there may be HERVs that are capable of infection. In addition, because HERVs are so ancient in the human lineage, evolution (...) of the human genome may have included the acquisition of some HERV genes for strictly cellular functions. (shrink)

This is a short entry on "Metatheatre" in Section 4, "Concepts, Themes and Topics Treated in the Dialogues," in The Bloomsbury Handbook of Plato, edited by Gerald Press and Mateo Duque.

This is a short entry on "Comedy" in Section 3, "Important Features of the Dialogues," in The Bloomsbury Handbook of Plato, edited by Gerald Press and Mateo Duque.

We expose some representations and practices related to the natural environment among Nahua peasants in a village located at the western boundary of Puebla and Guerrero states, in Mexico. Information was obtained by individual interviews and focal groups' work, following an open guide with ecological items considered as rooted in Mesoamerican cultures. The use of some local, vegetal resources, and the local perception of changes, mainly in the water availability, is documented. Survival strategies involve ancestral representations and material products, and (...) entail a high grade of pragmatism. “Natural environment” is framed in a local culture that involves relational and sacred dimensions, usually omitted in other approaches. Hence, for the Temalac peasants, there is no dissection, at an operative level, between “natural facts” and personal or social ones, being these often considered as determinant for the quality and accessibility of resources and weather conditions. We discuss the challenge for these elements posed by a growing migration rate and an increasing external influence. (shrink)

That endogenous retrovirus (ERV) is present within the placenta of humans and other mammals has been known for the past 25 years, but the significance of this observation is still not fully understood. Much molecular biological data have emerged in recent years to support the earlier electron microscopic data on the presence of placental ERV. The evidence for ERV in animal and human placental tissue is presented, then integrated with data on the the presence of ERV in a range (...) of other tissues, in particular teratocarcinoma cells. Placental invasiveness and maternal immunosuppression are then discussed in relation to metalloproteinase secretion, the immunosuppressive potential of retroviruses, and placental growth factors, while the evidence for a functional link between placental proto‐oncogenes and trophoblast malignancy is reviewed. Finally, placental development, structure, and life span are discussed within an evolutionary context. The hypothesis that one or more ancient trophoblastic ERVs could have played a role in the evolution and divergence of all placental mammals is evaluated. BioEssays 20:307‐316, 1998. © 1998 John Wiley & Sons, Inc. (shrink)

This entry provides an overview of some key positions on God and time and discusses arguments for and against divine timelessness. The final section outlines some other philosophical contexts in which the concept of eternity can play a role.

The beginning of the twenty first century has been characterized by the expansion of economics, politics and institutional relations. Using international case studies, this book illustrates the local answer to the challenge of increasing competition. The book introduces the idea of endogenous development, identifying the theoretical roots and defining its main features. It then goes on to indicate how this concept can be used to understand economic dynamics, and to show how the concept is relevant in economic analysis and (...) policy implementation in times of globalization. This work will be of essential interest to academics and policy-makers in planning and development economics. (shrink)

In Africa, the human person is the supreme force, the most powerful and dominant among all created beings. While this decreed power makes the lower beings subservient to humanity, it is only intended to be a source of harmony in the advancement of the hospitality and the joy of the human species. Today, however, the traditional lifestyles of Africans are threatened with virtual extinction by insensitive development over which the indigenous peoples have no participation. Africa has not only acquiesced a (...) scientific technology that has developed its own laws far removed from the known system of nature, it has no self-limiting principle in terms of size, speed and violence to nature and humanity. Consequent upon this incongruity, the machine has replaced the human person thus degrading the ecology and resources necessary for harmonious living. This chapter argues that, African endogenous knowledge is strategic heritage resource to salvage the technologically abused environment for sustainable agro-ecological living. The chapter argues further that African endogenous knowledge system encodes environmental management and policies for resource development in Africa’s complex and ageing ecological system. In doing this, we engage in conversation about current and potential land sovereignty work in African Indigenous communities. This will achieve food security and improved nutrition, promote sustainable agriculture and improved economic status of the African indigenous farmer. We conclude that, in seeking the whole from the units of the earth resources through cultivation of the soil, the African derives high credit balance of spiritual good, virtuous life, self-reliance, courage and moral integrity. (shrink)

Through a series of examples, we illustrate some important drawbacks that the action model logic framework suffers from in its ability to represent the dynamics of information updates. We argue that these problems stem from the fact that the action model, a central construct designed to encode agents’ uncertainty about actions, is itself effectively common knowledge amongst the agents. In response to these difficulties, we motivate and propose an alternative semantics that avoids them by endogenizing the action model. We discuss (...) the relationship between this new framework and action model logic, and provide a sound and complete axiomatization of several new logics that naturally arise. (shrink)

In eukaryotes, double‐stranded RNAs (dsRNAs) or short, interfering dsRNAs (siRNAs) can reduce the accumulation of a sequence‐related mRNA, often resulting in a loss‐of‐function phenotype—a process termed RNA interference (RNAi). Unfortunately, some mRNAs are resistant to the effects of dsRNA. Experiments designed to unravel RNAi mechanisms in Caenorhabditis elegans have led to the identification of two worm proteins, RRF‐31,2 and, now, ERI‐1,3 that can inhibit RNAi responses. Animals defective in either protein can display enhanced RNAi phenotypes for mRNAs that were previously (...) resistant to dsRNA. Since ERI‐1 is a conserved protein, development of procedures to enhance RNAi effectiveness in other systems may be possible. BioEssays 26:715–718, 2004. © 2004 Wiley Periodicals, Inc. (shrink)

It is widely recognized that computational theories of learning must posit the existence of a priori constraints on hypothesis selection. The present article surveys the theoretical options available for modelling the dynamic process whereby the constraints have their effect. According to the 'simplicity' theory (exemplified by Fodor's treatment), hypotheses are preference-ordered in terms of their syntactic or semantic properties. It is argued that the same explanatory power can be obtained with a weaker (hence better) theory, the 'minimalist' theory, which dispenses (...) with the preference ordering. According to the 'finitistic' theory, the learner is capable of generating only finitely many hypotheses for evaluation. Chomsky maintains that the occurrence of errorless learning in language acquisition necessitates a finististic explanation. Once again, there is a weaker theory that explains the same data. Finally, Goodman's argument to the effect that there cannot be a computational theory of learning is examined and rejected. (shrink)

The phenomenon of consciousness has received through the centuries a profusion of interpretations, engaging researchers across many disciplines. Nevertheless, consensus still floats at large. The aim of the present work is therefore twofold. Through the review of a selected number of existing proposals, it will first be considered the extents of their reciprocal compatibility, tentatively shaping an integrated, theoretical profile of consciousness. A new theory, the Endogenous Feedback Network will consequently be introduced which, besides being able to accommodate the (...) main tenets of the reviewed theories, appears able to compensate for the explanatory gaps they leave behind. The EFN proposes consciousness as the phenomenon emerging from a distinct neural network broadcasting the changes associated to mental activations across the brain. It additionally argues for the need to include a 5th element to Ned Block’s taxonomy that is, non-cognitive consciousness. (shrink)

We consider a two-player contest in which one contestant has a headstart advantage, but both can exert further effort. We allow the prize to depend on total performance in the contest and consider the respective cases in which efforts are productive and destructive of prize value. When the contest success function takes a logit form, and marginal cost is increasing in effort, we show that a Nash equilibrium exists and is unique both in productive and destructive endogenous prize contests. (...) In equilibrium, the underdog expends more resources to win the prize, but still his probability of winning remains below that of the favorite. In a productive contest, the underdog behaves more aggressively and wins the prize more often in comparison to a fixed-value contest. Thus, the degree of competitive balance—defined as the level of uncertainty of the outcome—depends upon the prize nature of the contest. (shrink)