2,934 research outputs found
A note on entropic uncertainty relations of position and momentum
We consider two entropic uncertainty relations of position and momentum
recently discussed in literature. By a suitable rescaling of one of them, we
obtain a smooth interpolation of both for high-resolution and low-resolution
measurements respectively. Because our interpolation has never been mentioned
in literature before, we propose it as a candidate for an improved entropic
uncertainty relation of position and momentum. Up to now, the author has
neither been able to falsify nor prove the new inequality. In our opinion it is
a challenge to do either one.Comment: 2 pages, 2 figures, 2 references adde
Quantum information entropies of the eigenstates and the coherent state of the P\"oschl-Teller potential
The position and momentum space information entropies, of the ground state of
the P\"oschl-Teller potential, are exactly evaluated and are found to satisfy
the bound, obtained by Beckner, Bialynicki-Birula and Mycielski. These
entropies for the first excited state, for different strengths of the potential
well, are then numerically obtained. Interesting features of the entropy
densities, owing their origin to the excited nature of the wave functions, are
graphically demonstrated. We then compute the position space entropies of the
coherent state of the P\"oschl-Teller potential, which is known to show revival
and fractional revival. Time evolution of the coherent state reveals many
interesting patterns in the space-time flow of information entropy.Comment: Revtex4, 11 pages, 11 eps figures and a tabl
Tripartism in comparative and historical perspective
This special issue explores changes in the nature of tripartite arrangements between firms, governments and organized labour across the last century, focusing on their post-1945 heyday. Although tripartism has its origins at the turn of the Twentieth Century, the post-1945 long boom represented an historical high-water mark that may now be seen as quite distinct from our own long period of volatility and crisis. Historical concerns are frequently stimulated by those of the present and this is especially the case in contemporary history. Anglo-Saxon historians may feel that the age of tripartism is at an end, but the contributions within this issue show that although this may accurately reflect current perceptions, tripartism continues , albeit often in weak forms, in other national and transnational contexts; its history therefore retains contemporary resonance.
In our present age, it is commonly assumed that the relative power of employers has increased at the expense of government – the central co-ordinating actor in tripartism – and organized labour. Within the firm, not only workers, but also traditional managers have been displaced by assertive investors and allied to them, a new managerial class that has little emotional capital sunk in the firm other than as a vehicle for shareholder value maximization or release, and personal enrichment. From the business historian’s viewpoint, these assumptions raise a number of issues surrounding long term trends and diversity in the nature of the capitalist ecosystem within which tripartism is located. In this connection, there are four alternative points of view on broad approaches to labour management. The first, rooted in the then apparent solidity of the British postwar tripartite settlement, was that the incorporation of labour’s institutions was structurally essential to the state’s role in avoiding or genuinely resolving crises. The second sees tripartism as very much an historical exception, representing to a large extent a product of a very specific set of historic circumstances around the Great Depression and the post-World War Two long boom. The third, a variant of the second, would see historic compromises between state, the firm, and workers as a reflection of the thirty year period of relative global prosperity and growth which had deeper historic roots stretching back at least into the Nineteenth Century. The fourth highlights national diversity in global capitalism and views the labour management options adopted according not only to temporal trends but also to such dimensions as space, scale, and global centre-periphery relations. The latter view implies that elements of post-war compromises may persist, even if, within many of the advanced societies, they do so in dilute form
A closer look at the uncertainty relation of position and momentum
We consider particles prepared by the von Neumann-L\"uders projection. For
those particles the standard deviation of the momentum is discussed. We show
that infinite standard deviations are not exceptions but rather typical. A
necessary and sufficient condition for finite standard deviations is given.
Finally, a new uncertainty relation is derived and it is shown that the latter
cannot be improved.Comment: 3 pages, introduction shortened, content unchange
Overview of the BioCreative III Workshop
<p>Abstract</p> <p>Background</p> <p>The overall goal of the BioCreative Workshops is to promote the development of text mining and text processing tools which are useful to the communities of researchers and database curators in the biological sciences. To this end BioCreative I was held in 2004, BioCreative II in 2007, and BioCreative II.5 in 2009. Each of these workshops involved humanly annotated test data for several basic tasks in text mining applied to the biomedical literature. Participants in the workshops were invited to compete in the tasks by constructing software systems to perform the tasks automatically and were given scores based on their performance. The results of these workshops have benefited the community in several ways. They have 1) provided evidence for the most effective methods currently available to solve specific problems; 2) revealed the current state of the art for performance on those problems; 3) and provided gold standard data and results on that data by which future advances can be gauged. This special issue contains overview papers for the three tasks of BioCreative III.</p> <p>Results</p> <p>The BioCreative III Workshop was held in September of 2010 and continued the tradition of a challenge evaluation on several tasks judged basic to effective text mining in biology, including a gene normalization (GN) task and two protein-protein interaction (PPI) tasks. In total the Workshop involved the work of twenty-three teams. Thirteen teams participated in the GN task which required the assignment of EntrezGene IDs to all named genes in full text papers without any species information being provided to a system. Ten teams participated in the PPI article classification task (ACT) requiring a system to classify and rank a PubMed<sup>®</sup> record as belonging to an article either having or not having “PPI relevant” information. Eight teams participated in the PPI interaction method task (IMT) where systems were given full text documents and were required to extract the experimental methods used to establish PPIs and a text segment supporting each such method. Gold standard data was compiled for each of these tasks and participants competed in developing systems to perform the tasks automatically.</p> <p>BioCreative III also introduced a new interactive task (IAT), run as a demonstration task. The goal was to develop an interactive system to facilitate a user’s annotation of the unique database identifiers for all the genes appearing in an article. This task included ranking genes by importance (based preferably on the amount of described experimental information regarding genes). There was also an optional task to assist the user in finding the most relevant articles about a given gene. For BioCreative III, a user advisory group (UAG) was assembled and played an important role 1) in producing some of the gold standard annotations for the GN task, 2) in critiquing IAT systems, and 3) in providing guidance for a future more rigorous evaluation of IAT systems. Six teams participated in the IAT demonstration task and received feedback on their systems from the UAG group. Besides innovations in the GN and PPI tasks making them more realistic and practical and the introduction of the IAT task, discussions were begun on community data standards to promote interoperability and on user requirements and evaluation metrics to address utility and usability of systems.</p> <p>Conclusions</p> <p>In this paper we give a brief history of the BioCreative Workshops and how they relate to other text mining competitions in biology. This is followed by a synopsis of the three tasks GN, PPI, and IAT in BioCreative III with figures for best participant performance on the GN and PPI tasks. These results are discussed and compared with results from previous BioCreative Workshops and we conclude that the best performing systems for GN, PPI-ACT and PPI-IMT in realistic settings are not sufficient for fully automatic use. This provides evidence for the importance of interactive systems and we present our vision of how best to construct an interactive system for a GN or PPI like task in the remainder of the paper.</p
Entropy and the uncertainty principle
We generalize, improve and unify theorems of Rumin, and Maassen--Uffink about
classical entropies associated to quantum density matrices. These theorems
refer to the classical entropies of the diagonals of a density matrix in two
different bases. Thus they provide a kind of uncertainty principle. Our
inequalities are sharp because they are exact in the high-temperature or
semi-classical limit.Comment: 6 page
Structural analysis of employment in the Brazilian economy: 1996 and 2002 compared
With the implementation, in 1994, of the Real plan in the Brazilian economy, and the consequent price stabilization, the analysis of structural aspects of the economy has gain in importance. Among these aspects, giving the needs for labor absorption in the economy, one of the main concerns relates to the question of employment. This paper deals with this by making an analysis of the changes in the employment in the Brazilian economy and relating these changes with the productive structure of the Brazilian economy between 1996 and 2002. To do it is made use of input-output matrices estimated for the Brazilian economy for these years and for 42 economic sectors, according to the methodology presented by Guilhoto and Sesso Fillho (2005). Through the use of these matrices, a series of indicators were estimated, which then, allowed to make an analysis of the structural aspects of the Brazilian economy and to relate if with the employment changes occurred in the period being considered
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