Doubly Perfect Nonlinear Boolean Permutations

Due to implementation constraints the XOR operation is widely used in order to combine plaintext and key bit-strings in secret-key block ciphers. This choice directly induces the classical version of the differential attack by the use of XOR-kind differences. While very natural, there are many alternatives to the XOR. Each of them inducing a new form for its corresponding differential attack (using the appropriate notion of difference) and therefore block-ciphers need to use S-boxes that are resistant against these nonstandard differential cryptanalysis. In this contribution we study the functions that offer the best resistance against a differential attack based on a finite field multiplication. We also show that in some particular cases, there are robust permutations which offers the best resistant against both multiplication and exponentiation base differential attacks. We call them doubly perfect nonlinear permutations

THE ECONOMIC AND POLITICAL IMPLICATIONS OF DEEP DRAFT USER FEES

Public Economics,

On differential uniformity of maps that may hide an algebraic trapdoor

We investigate some differential properties for permutations in the affine group, of a vector space V over the binary field, with respect to a new group operation $\circ$, inducing an alternative vector space structure on $V$ .Comment: arXiv admin note: text overlap with arXiv:1411.768

Features of spin-charge separation in the equilibrium conductance through finite rings

We calculate the conductance through rings with few sites $L$ described by the $t-J$ model, threaded by a magnetic flux $\Phi$ and weakly coupled to conducting leads at two arbitrary sites. The model can describe a circular array of quantum dots with large charging energy $U$ in comparison with the nearest-neighbor hopping $t$. We determine analytically the particular values of $\Phi$ for which a depression of the transmittance is expected as a consequence of spin-charge separation. We show numerically that the equilibrium conductance at zero temperature is depressed at those particular values of $\Phi$ for most systems, in particular at half filling, which might be easier to realize experimentally.Comment: 8 pages, 7 figure

On the generalized linear equivalence of functions over finite fields

In this paper we introduce the concept of generalized linear equivalence between functions defined over finite fields; this can be seen as an extension of the classical criterion of linear equivalence, and it is obtained by means of a particular geometric representation of the functions. After giving the basic definitions, we prove that the known equivalence relations can be seen as particular cases of the proposed generalized relationship and that there exist functions that are generally linearly equivalent but are not such in the classical theory. We also prove that the distributions of values in the Difference Distribution Table (DDT) and in the Linear Approximation Table (LAT) are invariants of the new transformation; this gives us the possibility to find some Almost Perfect Nonlinear (APN) functions that are not linearly equivalent (in the classical sense) to power functions, and to treat them accordingly to the new formulation of the equivalence criterion

Extension of nano-confined DNA: quantitative comparison between experiment and theory

The extension of DNA confined to nanochannels has been studied intensively and in detail. Yet quantitative comparisons between experiments and model calculations are difficult because most theoretical predictions involve undetermined prefactors, and because the model parameters (contour length, Kuhn length, effective width) are difficult to compute reliably, leading to substantial uncertainties. Here we use a recent asymptotically exact theory for the DNA extension in the "extended de Gennes regime" that allows us to compare experimental results with theory. For this purpose we performed new experiments, measuring the mean DNA extension and its standard deviation while varying the channel geometry, dye intercalation ratio, and ionic buffer strength. The experimental results agree very well with theory at high ionic strengths, indicating that the model parameters are reliable. At low ionic strengths the agreement is less good. We discuss possible reasons. Our approach allows, in principle, to measure the Kuhn length and effective width of a single DNA molecule and more generally of semiflexible polymers in solution.Comment: Revised version, 6 pages, 2 figures, 1 table, supplementary materia

Time trends in reported prevalence of kidney stones in the United States: 1976–199411.See Editorial by Goldfarb, p. 1951.

Time trends in reported prevalence of kidney stones in the United States: 1976–1994.BackgroundA body of evidence establishes that the occurrence of kidney stone disease has increased in some communities of industrialized countries. Information on recent temporal trends in the United States is lacking and population-based data on epidemiologic patterns are limited.Study objective was to determine whether kidney stone disease prevalence increased in the United States over a 20-year period and the influence of region, race/ethnicity, and gender on stone disease risk.MethodsWe measured the prevalence of kidney stone disease history from the United States National Health and Nutrition Examination Survey (II and III), population-based, cross-sectional studies, involving 15,364 adult United States residents in 1976 to 1980 and 16,115 adult United States residents in 1988 to 1994.ResultsDisease prevalence among 20- to 74-year-old United States residents was greater in 1988 to 1994 than in 1976 to 1980 (5.2% vs. 3.8%, P < 0.05), greater in males than females, and increased with age in each time period. Among 1988 to 1994 adults, non-Hispanic African Americans had reduced risk of disease compared to non-Hispanic Caucasians (1.7% vs. 5.9%, P < 0.05), and Mexican Americans (1.7% vs. 2.6%, P < 0.05). Also, age-adjusted prevalence was highest in the South (6.6%) and lowest in the West (3.3%). Findings were consistent across gender and multivariate adjusted odds ratios for stone disease history, including all demographic variables, as well as diuretic use, tea or coffee consumption, and dietary intake of calcium, protein, and fat did not materially change the results.ConclusionPrevalence of kidney stone disease history in the United States population increased between 1980 and 1994. A history of stone disease was strongly associated with race/ethnicity and region of residence

Effects of hatchery rearing and sea ranching of parents on the life history traits of released salmon offspring

Life-history traits such as growth, survival, sea migration and age at sexual maturity in the sea were compared between Carlin-tagged hatchery-reared Atlantic salmon smolts (Salmo salar) originating from hatchery broodstocks (reared) or naturally ascending spawners captured (sea ranched). The ranched parents included both wild (born in nature) and reared individuals (released as parr or smolts). All smolts were reared in similar hatchery conditions, and they were tagged and released as two-year-olds in the Simojoki River in 1986-2007. The recapture rates did not differ between the progeny groups, although the tagged smolts of the reared parents were larger than those of ranched parents at time of release. The captive salmon with ranched parents were at average heavier during their second winter at sea, but not later. Salmon with ranched parents more frequently migrated to feed in the Main Basin of the Baltic Sea, further from the home river of the salmon stock. The proportions of multi-sea-winter returners were 30% and 69% in salmon with reared and ranched parents, respectively. The different patterns of migration and sea age at maturity of these parental progeny groups suggest that differences in the life history of brood fish may cause distinct, possibly even genetic differences in the progenies. (c) 2013 Elsevier B.V. All rights reserved