In his thesis Para uma Teoria Geral dos Homomorfismos (1944), the Portuguese mathematician José Sebastião e Silva constructed an abstract or generalized Galois theory, that is intimately linked to F. Klein’s Erlangen Program and that foreshadows some notions and results of today’s model theory; an analogous theory was independently worked out by M. Krasner in 1938. In this paper, we present a version of the theory making use of tools which were not at Silva’s disposal. At the same time, we (...) tried to keep in mind, so much as possible, the gist of his standpoint. (shrink)
In his thesis 'Para uma Teoria Geral dos Homomorfismos' (1944) the Portuguese mathematician José Sebastião e Silva constructed an abstract or generalized Galois theory, that is intimately linked to F. Klein’s Erlangen Program and that foreshadows some notions and results of today’s model theory; an analogous theory was independently worked out by M. Krasner in 1938. In this paper, we present a version of the theory making use of tools which were not at Silva’s disposal. At the same time, we (...) tried to keep in mind, so much as possible, the gist of his standpoint. (shrink)
After recalling the rigorous mathematical representations in Relativity Theory (RT) of (i) observers, (ii) reference frames fields, (iii) their classifications, (iv) naturally adapted coordinate systems (nacs) to a given reference frame, (v) synchronization procedure and some other key concepts, we analyze three problems concerning experiments on rotating frames which even now (after almost a century after the birth of RT) are sources of misunderstandings and misconceptions. The first problem, which serves to illustrate the power of rigorous mathematical methods in RT, (...) is the explanation of the Sagnac effect (SE). This presentation is opportune because recently there have appeared many non sequitur claims in the literature stating that the SE cannot be explained by SRT, even disproving this theory or claiming that the explanation of the effect requires a new theory of electrodynamics. The second example has to do with the measurement of the one-way velocity of light in rotating reference frames, a problem about which many wrong statements appear in recent literature. The third problem has to do with claims that only Lorentz-like type transformations can be used between the nacs associated with a reference frame mathematically modeling of a rotating platform and the nacs associated with a inertial frame (the laboratory). We show that these claims are equivocal. (shrink)
In this paper we scrutinize the so called Principle of Local Lorentz Invariance (PLLI) that many authors claim to follow from the Equivalence Principle. Using rigourous mathematics, we introduce in the General Theory of Relativity two classes of reference frames (PIRFs and LLRFγs) which as natural generalizations of the concept of the inertial reference frames of the Special Relativity Theory. We show that it is the class of the LLRFγs that is associated with the PLLI. Next we give a definition (...) of physically equivalent reference frames. Then, we prove that there are models of General Relativity Theory (in particular on a Friedmann universe) where the PLLI is false. However our finding is not in contradiction with the many experimental claims vindicating the PLLI, because theses experiments do not have enough accuracy to detect the effect we found. We prove moreover that PIRFs are not physically equivalent. (shrink)
Given an argumentation network with initial values to the arguments, we look for algorithms which can yield extensions compatible with such initial values. We find that the best way of tackling this problem is to offer an iteration formula that takes the initial values and the attack relation and iterates a sequence of intermediate values that eventually converges leading to an extension. The properties surrounding the application of the iteration formula and its connection with other numerical and non-numerical techniques proposed (...) by others are thoroughly investigated in this paper. (shrink)
There is a generic way to add any new feature to a system. It involves identifying the basic units which build up the system and introducing the new feature to each of these basic units. In the case where the system is argumentation and the feature is probabilistic we have the following. The basic units are: the nature of the arguments involved; the membership relation in the set S of arguments; the attack relation; and the choice of extensions. Generically to (...) add a new aspect to an argumentation network \ can be done by adding this feature to each component. This is a brute-force method and may yield a non-intuitive or meaningful result. A better way is to meaningfully translate the object system into another target system which does have the aspect required and then let the target system endow the aspect on the initial system. In our case we translate argumentation into classical propositional logic and get probabilistic argumentation from the translation. Of course what we get depends on how we translate. In fact, in this paper we introduce probabilistic semantics to abstract argumentation theory based on the equational approach to argumentation networks. We then compare our semantics with existing proposals in the literature including the approaches by M. Thimm and by A. Hunter. Our methodology in general is discussed in the conclusion. (shrink)
BackgroundClinical ethics consultations can be complex interventions, involving multiple methods, stakeholders, and competing ethical values. Despite longstanding calls for rigorous evaluation in the field, progress has been limited. The Medical Research Council proposed guidelines for evaluating the effectiveness of complex interventions. The evaluation of CEC may benefit from application of the MRC framework to advance the transparency and methodological rigor of this field. A first step is to understand the outcomes measured in evaluations of CEC in healthcare settings. ObjectiveThe primary (...) objective of this review was to identify and map the outcomes reported in primary studies of CEC. The secondary objective was to provide a comprehensive overview of CEC structures, processes, and roles to enhance understanding and to inform standardization.MethodsWe searched electronic databases to identify primary studies of CEC involving patients, substitute decision-makers and/or family members, clinicians, healthcare staff and leaders. Outcomes were mapped across five conceptual domains as identified a priori based on our clinical ethics experience and preliminary literature searches and revised based on our emerging interpretation of the data. These domains included personal factors, process factors, clinical factors, quality, and resource factors. ResultsForty-eight studies were included in the review. Studies were highly heterogeneous and varied considerably regarding format and process of ethical intervention, credentials of interventionist, population of study, outcomes reported, and measures employed. In addition, few studies used validated measurement tools. The top three outcome domains that studies reported on were quality, process factors, and clinical factors. The majority of studies examined multiple outcome domains. All five outcome domains were multidimensional and included a variety of subthemes.ConclusionsThis scoping review represents the initial phase of mapping the outcomes reported in primary studies of CEC and identifying gaps in the evidence. The confirmed lack of standardization represents a hindrance to the provision of high quality intervention and CEC scientific progress. Insights gained can inform the development of a core outcome set to standardize outcome measures in CEC evaluation research and enable scientifically rigorous efficacy trials of CEC. (shrink)
Ion channels are transport proteins present in the lipid bilayers of biological membranes. They are involved in many physiological processes, such as the generation of nerve impulses, hormonal secretion, and heartbeat. Conformational changes in the ion channel-forming protein allow the opening or closing of pores to control the ionic flux through the cell membranes. The opening and closing of the ion channel have been classically treated as a random kinetic process, known as a Markov process. Here the time the channel (...) remains in a given state is assumed to be independent of the condition it had in the previous state. More recently, however, several studies have shown that this process is not random but a deterministic one, where both the open and closed dwell-times and the ionic current flowing through the channel are history-dependent. This property is called long memory or long-range correlation. However, there is still much controversy regarding how this memory originates, which region of the channel is responsible for this property, and which models could best reproduce the memory effect. In this article, we provide a review of what is, where it is, its possible origin, and the mathematical methods used to analyze the long-term memory present in the kinetic process of ion channels. (shrink)
This paper introduces the logic _Q__L__E__T_ _F_, a quantified extension of the logic of evidence and truth _L__E__T_ _F_, together with a corresponding sound and complete first-order non-deterministic valuation semantics. _L__E__T_ _F_ is a paraconsistent and paracomplete sentential logic that extends the logic of first-degree entailment (_FDE_) with a classicality operator ∘ and a non-classicality operator ∙, dual to each other: while ∘_A_ entails that _A_ behaves classically, ∙_A_ follows from _A_’s violating some classically valid inferences. The semantics of _Q__L__E__T_ (...) _F_ combines structures that interpret negated predicates in terms of anti-extensions with first-order non-deterministic valuations, and completeness is obtained through a generalization of Henkin’s method. By providing sound and complete semantics for first-order extensions of _FDE_, _K3_, and _LP_, we show how these tools, which we call here the method of _anti-extensions + valuations_, can be naturally applied to a number of non-classical logics. (shrink)
Delusion is one of the most intriguing psychopathological phenomena and its conceptualization remains the subject of genuine debate. Claims that it is ill-defined, however, are typically grounded on essentialist expectations that a given definition should capture the core of every instance acknowledged as delusion in the clinical setting.
In August 2021, Froese et al. published survey data collected from 2,543 respondents on their subjective experiences living under imposed social distancing measures during COVID-19 (1). The questionnaire was issued to respondents in the UK, Japan, and Mexico. By combining the authors’ expertise in phenomenological philosophy, phenomenological psychopathology, and enactive cognitive science, the questions were carefully phrased to prompt reports that would be useful to phenomenological investigation and theorizing (2–4). These questions reflected the various author’s research interests (e.g., technology, grief, (...) time). Between April 7th and July 31st, 2021, a second questionnaire with the same question set was issued to respondents of the original who had agreed to do a follow-up. This was intended to capture subjective reports of life under social distancing measures a year after the initial survey. By this time–depending on their country of residence and health status–respondents had potentially lived with repeated and prolonged lockdowns and a variety of other restrictions on their social lives. When taken together, Survey I and Survey II provide a cross-cultural and longitudinal dataset that allows for analysis of longer-term impacts of imposed social distancing measures on people’s experiences. For researchers working in diverse disciplines, this dataset offers a rich resource that reflects people’s reactions to the imposition of different social restrictions in different countries and over different time periods. (shrink)
Chervenak and McCullough, authors of the most acknowledged ethical framework for maternal–fetal surgery, rely on the ‘ethical–obstetrical’ concept of the fetus as a patient in order to determine what is morally owed to fetuses by both physicians and the women who gestate them in the context of prenatal surgery. In this article, we reconstruct the argumentative structure of their framework and present an internal criticism. First, we analyse the justificatory arguments put forward by the authors regarding the moral status of (...) the fetus qua patient. Second, we discuss the internal coherence and consistency of the moral obligations those authors derive from that concept. We claim that some of the dilemmas their approach is purported to avoid, such as the debate about the independent moral status of the fetus, and the foundation of the moral obligations of pregnant women (towards the fetuses they gestate) are not, all things considered, avoided. Chervenak and McCullough construct the obligations of physicians as obligations towards entities with equal moral status. But, at the same time, they assume that the woman has an independent moral status while the moral status of the fetus is dependent on the decision of the woman to present it to a physician for care. According to the logic of their own argumentation, Chervenak and McCullough implicitly admit a different moral status of the woman and the fetus, which will lead to different ascription of duties of the physician than those they ascribed. (shrink)
This article focuses on maternal-fetal surgery (MFS) and on the concept of clinical equipoise that is a widely accepted requirement for conducting randomized controlled trials (RCT). There are at least three reasons why equipoise is unsuitable for MFS. First, the concept is based on a misconception about the nature of clinical research and the status of research subjects. Second, given that it is not clear who the research subject/s in MFS is/are, if clinical equipoise is to be used as a (...) criterion to test the ethical appropriateness of RCT, its meaning should be unambiguous. Third, because of the multidisciplinary character of MFS, it is not clear who should be in equipoise. As a result, we lack an adequate criterion for the ethical review of MFS protocols. In our account, which is based on Chervenak and McCullough's seminal work in the field of obstetric ethics, equipoise is abandoned. and RCT involving MFS can be ethically initiated when a multidisciplinary ethics review board (ERB), having an evidence-based assessment of the risks involved, is convinced that the value of answering the research hypothesis, for the sake of the health interests of future pregnant women carrying fetuses with certain congenital birth defects, justifies the actual risks research participants might suffer within a set limit of low/manageable. (shrink)
Este artículo tiene como objetivo presentar un modelo de comprensión tal que permita a la investigación pastoral reflexionar sobre cómo la traditio fidei se puede realizar con el recurso de entornos digitales. Para eso, recurre a la mediología de Régis Debray, reflexionando sobre el modo como los componentes de la cultura digital pueden estar al servicio de la transmisión cultural.
Live donor kidney transplantation is the best treatment option for most patients with late-stage chronic kidney disease; however, the rate of living kidney donation has declined in the United States. A consensus conference was held June 5-6, 2014 to identify best practices and knowledge gaps pertaining to live donor kidney transplantation and living kidney donation. Transplant professionals, patients, and other key stakeholders discussed processes for educating transplant candidates and potential living donors about living kidney donation; efficiencies in the living donor (...) evaluation process; disparities in living donation; and financial and systemic barriers to living donation. We summarize the consensus recommendations for best practices in these educational and clinical domains, future research priorities, and possible public policy initiatives to remove barriers to living kidney donation. (shrink)
SÍNTESE - Um dos aspectos mais amplamente abordados em estudos recentes de Filosofia da Ciência tem sido o debate epistemológico criado em tomo das idéias de Thomas Kuhn e Karl Popper. Na tentativa de resolver a controvérsia estabelecida, Imre Lakatos propôs a falsificação metodológica sofisticada. O presente artigo coloca em foco esta proposição, discutindo sua formulação e destacando a contribuição de Lakatos ao raciocinio epistemológico. PALAVRAS-CHAVE - filosofia da ciência, Lakatos, falsificação metodológica.
High-level improvising musicians master idiosyncratic gesture vocabularies that allow them to express themselves in unique ways. The full use of such vocabularies is nevertheless challenged when improvisers incorporate electronics in their performances. To control electronic sounds and effects, they typically use commercial interfaces whose physicality is likely to limit their freedom of movement. Based on Jim Black's descriptions of his ideal digital musical instrument, embodied improvisation gestures, and stage performance constraints, we develop the concept of a modular wearable MIDI interface (...) to closely meet the needs of professional improvisers, rather than proposing a new generic instrument that would require substantial practice to adapt improvisational techniques already acquired. Our research draws upon different bodies of knowledge, from theoretical principles on collaboration and embodiment to wearable interface design, in order to create a digital vest called Track It, Zip It that features two innovative on-body sensors. Allowing for sound control, these sensors are seamlessly integrated with Black's improvisational gesture vocabulary. We then detail the design process of three TIZI prototypes structured by the outcomes of a performance test with Black, a public performance by a novice improviser during the 2017 International Guthman Musical Instrument Competition, and measurements of sensor responses. After commenting on the strengths and weaknesses of the final TIZI prototype, we discuss how our interdisciplinary and collective process involving a world-class improviser at the very center of the design process can provide recommendations to designers who wish to create interfaces better adapted to high-level performers. Finally, we present our goals for the future creation of a wireless version of the vest for a female body based on Diana Policarpo's artistic vision. (shrink)
The purpose of the present paper is to reply to a misleading paper by M. Sachs entitled “Einstein's later view of the Twin Paradox” (TP) (Found. Phys. 15, 977 (1985)). There, by selecting some passages from Einstein's papers, he tried to convince the reader that Einstein changed his mind regarding the asymmetric aging of the twins on different motions. Also Sachs insinuates that he presented several years ago “convincing mathematical arguments” proving that the theory of relativity does not predict asymmetrical (...) aging in the TP. Here we give a definitive treatment to the clocks problem showing that Sachs' “convincing mathematical arguments” are non sequitur. Also, by properly quoting Einstein, we show that his later view of the TP coincides with the one derived from the rigorous theory of time developed in this paper. (shrink)
SummaryIn 1905 the Campos Rodrigues Observatory was founded in Lourenço Marques, the capital of Mozambique, by then part of the Portuguese overseas empire. In this paper the inception and early history of the CRO are analysed in the broader context of the interwoven history of the Portuguese and British empires in Africa, and specifically with respect to the scientific relations between Mozambique and South Africa. The equipment, personnel, practices and networks involved in the inception and early development of the (...) CRO are brought into focus in order to illustrate the problems and strategies that shaped the establishment and functioning of this observatory, which was conceived essentially as a symbol of imperial stamina and colonial prowess. It is suggested that by providing a focal point for the development of scientific relations between Mozambique and South Africa, the CRO served both Portuguese ambitions for recognition as an imperial power and the emergence of South African nationalism. (shrink)
Este texto propõe discutir a controvérsia sobre o uso dos transgênicos na agricultura e pergunta também pela possibilidade de uma alternativa melhor a eles. Quando falamos em controvérsia, referimo-nos a uma discussão sobre ideias que refletem posturas opostas. Serão, portanto, apresentadas duas perspectivas distintas a respeito do tema: a perspectiva dos proponentes da transgenia e a dos críticos. A partir da perspectiva crítica, a agroecologia será elencada como possível alternativa para produção de alimentos considerando sua dimensão ética.
The advanced donation program was proposed in 2014 to allow an individual to donate a kidney in order to provide a voucher for a kidney in the future for a particular loved one. In this article, we explore the logistical and ethical issues that such a program raises. We argue that such a program is ethical in principle but there are many logistical issues that need to be addressed to ensure that the actual program is fair to both those who (...) do and do not participate in this program. (shrink)
We retrieve Bakhtin's reflections on Forms of Time and the Chronotope in the Novel present in The Dialogic Imagination: Four Essays by M. M. Bakhtin in order to verify the variations of the 'Ancient Biography and Autobiography Chronotope' in contemporary autobiography novel. We thus analyze the chronotope in the autobiography novels A Moveable Feast, by Ernest Hemingway, and Chá das cinco com o vampire [Afternoon Tea with the Vampire], by the Brazilian writer Miguel Sanches Neto. Our reading of Bakhtin's notion (...) of chronotope in these narratives leads us to relate the form of public and private space configuration with different strategies of representation. (shrink)
Although corporate social innovation studies in developing countries acknowledge the importance of firm resources and capabilities for attaining social goals, they overlook the way in which these interact with broader institutions to generate successful outcomes. We address this gap by exploring the relationship between firm resources-capabilities and institutions that is conducive to meeting both business and social interests in developing countries. By employing a fuzzy-set qualitative comparative analysis of corporate social innovation projects performed by joint ventures of Dutch SMEs and (...) their local partners in developing countries, we show that firm resources and/or capabilities complement strong institutions in these countries. Corporate social innovation can also be facilitated by firm capabilities in running highly legitimate projects that substitute institutional voids in these economies, attesting to multiple paths that corporations can take to achieve social innovation. (shrink)
This paper reviews the central points and presents some recent developments of the epistemic approach to paraconsistency in terms of the preservation of evidence. Two formal systems are surveyed, the basic logic of evidence (BLE) and the logic of evidence and truth (LET J ), designed to deal, respectively, with evidence and with evidence and truth. While BLE is equivalent to Nelson’s logic N4, it has been conceived for a different purpose. Adequate valuation semantics that provide decidability are given for (...) both BLE and LET J . The meanings of the connectives of BLE and LET J , from the point of view of preservation of evidence, is explained with the aid of an inferential semantics. A formalization of the notion of evidence for BLE as proposed by M. Fitting is also reviewed here. As a novel result, the paper shows that LET J is semantically characterized through the so-called Fidel structures. Some opportunities for further research are also discussed. (shrink)
Background: The magnitude of bullying and harassment among psychiatrists is reportedly high, yet no peer-review published studies addressing this issue could be found. Therefore, it was decided to conduct a pilot study to assess the degree of the problem, the types of bullying/harassment and to provide some insights into the situation.Methods and Principal Findings: Following multiple focus group meetings, a yes/no response type questionnaire was developed to assess the degree and type of bullying and harassment experienced by psychiatrists. Over a (...) 3-month period the questionnaire was administered to a random sample of 60 psychiatrists. 57 out of the 60 psychiatrists reported harassment and bullying. Frequencies of the following response variables are presented in descending order: rumours 40% ; defamation 20% ; passing remarks 20% ; false accusations 15% ; threats 13.3% ; verbal abuse 13.3% ; unjustified complaints 13.3% ; promotion blocked 13.3% ; humiliation 13% ; bad reference given 10% ; credentials questioned 8.3% ; physical attacks 5% ; termination 5% ; derogatory remarks 1.7% and 1.7% were subjected to personal work. As a result of being subjected to harassment, 66.7% of the psychiatrists did not take any action, whereas 33.3% confronted the person they believed responsible. Asked whether the bullying and harassment caused distress, 18.3% of the psychiatrists did not report any effect, 30% reported mild distress, 40% moderate distress and severe distress was reported by 11.7%.Conclusions: It was concluded that the magnitude of bullying and harassment among psychiatrists may be quite high, as evidenced by this pilot study. There is a need for extensive systematic studies on this subject and to establish strategies to prevent and address this issue at a national and regulatory level. (shrink)
In the years 1878 and 1879 the American physicist Alfred Marshall Mayer published his experiments with floating magnets as a didactic illustration of molecular actions and forms. A number of physicists made use of this analogy of molecular structure. For William Thomson they were a mechanical illustration of the kinetic equilibrium of groups of columnar vortices revolving in circles round their common centre of gravity . A number of modifications of Mayer's experiments were described, which gave configurations which were more (...) or less analogous to Mayer's arrangements. It was Joseph John Thomson who, in publications between 1897 and 1907, used Mayer's results to obtain a good deal of insight into the general laws which govern the configuration of the electrons in his atomic model. This article is mainly concerned with Mayer's experiments with floating magnets and their use by a number of physicists. Through his experiments Mayer made a significant, although small, contribution to the theory of atomic structure. (shrink)
This volume is an introduction to the philosophy of William of Ockham. After a brief account of his life and works, it presents his philosophical ideas under the headings of logic, epistemology, metaphysics, rational theology, philosophy of nature, psychology, ethics, and politics. The work concludes with a bibliography on Ockham and Ockhamism from 1950 to 1970, supplementing that of V. Heynck from 1919 to 1949. This is a well-informed presentation of Ockham’s philosophical ideas. Covering the whole range of his philosophy, (...) it does not treat any part of it in depth; but, as Fr. Bettoni says in his introduction, it offers a new global perspective on Ockham’s thought. There are frequent citations from Ockham’s writings in the notes, indicating the author’s close reading of Ockham’s works. The author is well aware that Ockham was "a philosopher who never ceases to be a theologian". But he does not convey to his reader the fact that Ockham’s interests, like those of Aquinas and Scotus, were primarily theological and not philosophical; that Ockham developed a logic and philosophy in support of a theology. The title of the work "Guglielmo di Ockham" suggests that the Ockham presented in it—Ockham the philosopher, not Ockham the theologian—was the "essential" Ockham.—A. A. M. (shrink)
In different papers, Carnielli, W. & Rodrigues, A., Carnielli, W. Coniglio, M. & Rodrigues, A. and Rodrigues & Carnielli, present two logics motivated by the idea of capturing contradictions as conflicting evidence. The first logic is called BLE and the second—that is a conservative extension of BLE—is named LETJ. Roughly, BLE and LETJ are two non-classical logics in which the Laws of Explosion and Excluded Middle are not admissible. LETJ is built on top of BLE. Moreover, LETJ (...) is a Logic of Formal Inconsistency. This means that there is an operator that, roughly speaking, identifies a formula as having classical behavior. Both systems are motivated by the idea that there are different conditions for accepting or rejecting a sentence of our natural language. So, there are some special introduction and elimination rules in the theory that are capturing different conditions of use. Rodrigues & Carnielli’s paper has an interesting and challenging idea. According to them, BLE and LETJ are incompatible with dialetheia. It seems to show that these paraconsistent logics cannot be interpreted using truth-conditions that allow true contradictions. In short, BLE and LETJ talk about conflicting evidence avoiding to talk about gluts. I am going to argue against this point of view. Basically, I will firstly offer a new interpretation of BLE and LETJ that is compatible with dialetheia. The background of my position is to reject the one canonical interpretation thesis: the idea according to which a logical system has one standard interpretation. Then, I will secondly show that there is no logical basis to fix that Rodrigues & Carnielli’s interpretation is the canonical way to establish the content of logical notions of BLE and LETJ. Furthermore, the system LETJ captures inside classical logic. Then, I am also going to use this technical result to offer some further doubts about the one canonical interpretation thesis. (shrink)
ISI Books' Crosscurrents series makes available in English-usually for the first time-new translations of both classic and contemporary works by authors working within, or with crucial importance for, the conservative, religious, and humanist intellectual traditions. Book jacket.
Mental health practitioners often come across a number of challenges in their clinical practice. One such challenge that posed a management dilemma presented with the history of reincarnation. This subject has been discussed in non-scientific literature at length but there is an absolute paucity in scientific literature. This paper describes a case where a boy presented with memories of previous life that started haunting him and caused significant anxiety. The subject of reincarnation needs extensive research in order to understand and (...) manage the resultant clinical challenges. (shrink)
We present the opinion of some authors who believe there is no force between a stationary charge and a stationary resistive wire carrying a constant current. We show that this force is different from zero and present its main components: the force due to the charges induced in the wire by the test charge and a force proportional to the current in the resistive wire. We also discuss briefly a component of the force proportional to the square of the current (...) which should exist according to some models and another component due to the acceleration of the conduction electrons in a curved wire carrying a dc current (centripetal acceleration). Finally, we analyze experiments showing the existence of the electric field proportional to the current in resistive wires. (shrink)
The nature of quantum computation is discussed. It is argued that, in terms of the amount of information manipulated in a given time, quantum and classical computation are equally efficient. Quantum superposition does not permit quantum computers to ''perform many computations simultaneously'' except in a highly qualified and to some extent misleading sense. Quantum computation is therefore not well described by interpretations of quantum mechanics which invoke the concept of vast numbers of parallel universes. Rather, entanglement makes available types of (...) computation processes which, while not exponentially larger than classical ones, are unavailable to classical systems. The essence of quantum computation is that it uses entanglement to generate and manipulate a physical representation of the correlations between logical entities, without the need to completely represent the logical entities themselves. (shrink)