Visual illusions of movement

Visual illusions related to involuntary eye movemen

Polynomial-Time Algorithms for Prime Factorization and Discrete Logarithms on a Quantum Computer

A digital computer is generally believed to be an efficient universal computing device; that is, it is believed able to simulate any physical computing device with an increase in computation time of at most a polynomial factor. This may not be true when quantum mechanics is taken into consideration. This paper considers factoring integers and finding discrete logarithms, two problems which are generally thought to be hard on a classical computer and have been used as the basis of several proposed cryptosystems. Efficient randomized algorithms are given for these two problems on a hypothetical quantum computer. These algorithms take a number of steps polynomial in the input size, e.g., the number of digits of the integer to be factored.Comment: 28 pages, LaTeX. This is an expanded version of a paper that appeared in the Proceedings of the 35th Annual Symposium on Foundations of Computer Science, Santa Fe, NM, Nov. 20--22, 1994. Minor revisions made January, 199

Monensin-dependent and -independent mechanisms of cell-matrix adhesion

AbstractAttachment and spreading of human FL cells on a subcellular matrix (SCM) preparation made by treating confluent cell monolayers with deoxycholate are insensitive to the presence of monensin. However, if the cell suspension is surface-iodinated prior to adhesion using the LPO/H2O2 system, cell spreading on SCM is inhibited by 1 μM monensin. The suggested interpretation is that cell surface components required for cell spreading on SCM are inactivated by iodination and need replacement from intracellular reserves by a monensin-sensitive pathway. This pathway is not required in the absence of iodination when sufficient surface components (or a monensin-independent pathway of surface expression) are available. Support for this interpretation is obtained by means of double-iodination experiments in which surface-labelled cells adhere and spread, are detached and labelled a second time and then allowed to adhere again to SCM. Cell spreading in the second case is inhibited by ~ 80%, suggesting that both previously expressed and newly recruited receptors are inactivated

Exactness of the Original Grover Search Algorithm

It is well-known that when searching one out of four, the original Grover's search algorithm is exact; that is, it succeeds with certainty. It is natural to ask the inverse question: If we are not searching one out of four, is Grover's algorithm definitely not exact? In this article we give a complete answer to this question through some rationality results of trigonometric functions.Comment: 8 pages, 2 figure

Occupational class differences in suicide: evidence of changes over time and during the global financial crisis in Australia

BACKGROUND: Previous research showed an increase in Australian suicide rates during the Global Financial Crisis (GFC). There has been no research investigating whether suicide rates by occupational class changed during the GFC. The aim of this study was to investigate whether the GFC-associated increase in suicide rates in employed Australians may have masked changes by occupational class. METHODS: Negative binomial regression models were used to investigate Rate Ratios (RRs) in suicide by occupational class. Years of the GFC (2007, 2008, 2009) were compared to the baseline years 2001-2006. RESULTS: There were widening disparities between a number of the lower class occupations and the highest class occupations during the years 2007, 2008, and 2009 for males, but less evidence of differences for females. CONCLUSIONS: Occupational disparities in suicide rates widened over the GFC period. There is a need for programs to be responsive to economic downturns, and to prioritise the occupational groups most affected

Global periodicity conditions for maps and recurrences via Normal Forms

We face the problem of characterizing the periodic cases in parametric families of (real or complex) rational diffeomorphisms having a fixed point. Our approach relies on the Normal Form Theory, to obtain necessary conditions for the existence of a formal linearization of the map, and on the introduction of a suitable rational parametrization of the parameters of the family. Using these tools we can find a finite set of values p for which the map can be p-periodic, reducing the problem of finding the parameters for which the periodic cases appear to simple computations. We apply our results to several two and three dimensional classes of polynomial or rational maps. In particular we find the global periodic cases for several Lyness type recurrences.Comment: 25 page

What to Expect from Sectoral Trading: A U.S.–China Example

Abstract and PDF report are also available on the MIT Joint Program on the Science and Policy of Global Change website (http://globalchange.mit.edu/)In recent United Nations Framework Convention on Climate Change (UNFCCC) negotiations, sectoral mechanisms were proposed as a way to encourage early action and spur investment in low carbon technologies in developing countries, particularly in the electricity sector. Sectoral trading, which is one such proposition, involves including a sector from one or more nations in an international cap-and-trade system. In order to assess potential impacts from such a mechanism, we analyze trade in carbon permits between the Chinese electricity sector and a U.S. economy-wide cap-and-trade program using the MIT Emissions Prediction and Policy Analysis (EPPA) model. We find that this sectoral policy induces significant financial transfers between the two countries. In 2030, the U.S. purchases permits valued at $42 billion from China, which represents more than 46% of its capped emissions. Despite these transfers, there is only a small change in Chinese welfare. In the U.S., the availability of relatively cheap emissions permits significantly reduces the cost of climate policy. In China, sectoral trading increases the price of electricity and reduces the amount of electricity generated, particularly from coal, while opposite effects are observed in the U.S. Despite increases in the price of electricity in China, only small increases in electricity generation from nuclear and renewables are projected in the timeframe of our analysis (2010- 2030). Because the price of coal decree ses, we also find that sectoral trading leads to emissions increases in non-electricity sectors in China, a form of internal carbon leakage.This study received support from the MIT Joint Program on the Science and Policy of Global Change, which is funded by a consortium of government, industry and foundation sponsors

Electron-electron interaction corrections to the thermal conductivity in disordered conductors

We evaluate the electron-electron interaction corrections to the electronic thermal conductivity in a disordered conductor in the diffusive regime. We use a diagrammatic many-body method analogous to that of Altshuler and Aronov for the electrical conductivity. We derive results in one, two and three dimensions for both the singlet and triplet channels, and in all cases find that the Wiedemann-Franz law is violated.Comment: 8 pages, 2 figures Typos corrected in formulas (15) and (A.4) and Table 1; discussion of previous work in introduction extended; reference clarifying different definitions of parameter F adde