Limits on the Usefulness of Random Oracles

In their seminal work, Impagliazzo and Rudich (STOC’89) showed that no key-agreement protocol exists in the random-oracle model, yielding that key agreement cannot be black-box reduced to one-way functions. In this work, we generalize their result, showing that, to a large extent, no-private-input, semi-honest, two-party functionalities that can be securely implemented in the random oracle model can be securely implemented information theoretically (where parties are assumed to be all powerful, and no oracle is given). Using a recent information-theoretic impossibility result by McGregor et al. (FOCS’10), our result yields that certain functionalities (e.g. inner product) cannot be computed both in an accurately and in a differentially private manner in the random oracle model, implying that protocols for computing these functionalities cannot be black-box reduced to the existence of one-way functions.     

Dietary intake and stress fractures among elite male combat recruits

Background

We examined the effect of four weeks of ??-alanine supplementation on isometric endurance of the knee extensors at 45% maximal voluntary isometric contraction (MVIC).

Methods

Thirteen males (age 23?±?6 y; height 1.80?±?0.05?m; body mass 81.0?±?10.5?kg), matched for pre-supplementation isometric endurance, were allocated to either a placebo (n?=?6) or ??-alanine (n?=?7; 6.4?g·d^-1 over 4?weeks) supplementation group. Participants completed an isometric knee extension test (IKET) to fatigue, at an intensity of 45% MVIC, before and after supplementation. In addition, two habituation tests were completed in the week prior to the pre-supplementation test and a further practice test was completed in the week prior to the post-supplementation test. MVIC force, IKET hold-time, and impulse generated were recorded.

Results

IKET hold-time increased by 9.7?±?9.4?s (13.2%) and impulse by 3.7?±?1.3 kN·s^-1 (13.9%) following ??-alanine supplementation. These changes were significantly greater than those in the placebo group (IKET: t ₍₁₁₎?=?2.9, p ??0.05; impulse: t ₍₁₁₎?=?3.1, p????0.05). There were no significant changes in MVIC force in either group.

Conclusion

Four weeks of ??-alanine supplementation at 6.4?g·d^-1 improved endurance capacity of the knee extensors at 45% MVIC, which most likely results from improved pH regulation within the muscle cell as a result of elevated muscle carnosine levels.     

Al Mansfeld and the interpretation of the Israel Museum

Over the past few decades, the Israel Museum in Jerusalem has been the subject of post-colonial interpretations which likened the organisation of the pavilions that make up the museum to the form of an Arab village. Focusing on the organisational and formal similarities between the museum and the typology of the Arab village, these interpretations propose that Israel, even before the 1967 War and the conquest of the West Bank and Gaza Strip, had already begun to appropriate Palestinian symbols. These interpretations often refer to drawings made by Al Mansfeld, the museum's architect. This essay argues that while the post-colonial interpretations may be correct, they neglect to address yet another big influence on Mansfeld's thinking when he conceptualised the Israel Museum in the late 1950s. During the early 1930s in Berlin, Mansfeld was a student of two German Expressionist architects, Hans Poelzig and Heinrich Tessenow. During these years, Mansfeld was exposed to expressionist ideas about architecture that later permeated his designs and artwork, including the design of the Israel Museum.     

A response to Gazzaniga: Language in the right hemisphere, convergent perspectives.

Responds to M. S. Gazzaniga's (see record 1984-07149-001) review of right-hemisphere language in split-brain patients. The present author contests Gazzaniga's assumption that, without language, right-hemisphere cognition shows no purpose, representing only an early phylogenetic and ontogenetic stage of development. The present author presents evidence from some of the same patients studied by Gazzaniga (the California series), the right hemisphere in aphasics, and language in normal right hemispheres to refute Gazzaniga's hypothesis that overall cognitive competence of the right hemisphere freezes at the time language processes are consolidated in the left hemisphere. Evidence for right-hemisphere involvement in normal language is becoming increasingly evident. (26 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Melting and burning solids into liquids and gases

We propose a novel technique for melting and burning solid materials, including the simulation of the resulting liquid and gas. The solid is simulated with traditional mesh-based techniques (triangles or tetrahedra) which enable robust handling of both deformable and rigid objects, collision and self-collision, rolling, friction, stacking, etc. The subsequently created liquid or gas is simulated with modern grid-based techniques, including vorticity confinement and the particle level set method. The main advantage of our method is that state-of-the-art techniques are used for both the solid and the fluid without compromising simulation quality when coupling them together or converting one into the other. For example, we avoid modeling solids as Eulerian grid-based fluids with high viscosity or viscoelasticity, which would preclude the handling of thin shells, self-collision, rolling, etc. Thus, our method allows one to achieve new effects while still using their favorite algorithms (and implementations) for simulating both solids and fluids, whereas other coupling algorithms require major algorithm and implementation overhauls and still fail to produce rich coupling effects (e.g., melting and burning solids).     

Control of sulfide in sewer systems by dosage of iron salts: comparison between theoretical and experimental results, and practical implications

Removal of sulfide species from municipal sewage conveyance systems by dosage of iron salts is a relatively common practice. However, the reactions that occur between dissolved iron and sulfide species in municipal sewage media have not yet been fully quantified, and practical application relies heavily on empirical experience, which is often site specific. The aim of this work was to combine theoretical considerations and empirical observations to enable a more reliable prediction of the sulfide removal efficiency for a given dosing strategy. Two main questions were addressed, regarding the dominant sulfur species that results from the oxidation of sulfide by Fe(III) and the dominant precipitation reaction between Fe(II) and sulfide species. Comparison of thermodynamic prediction obtained by an equilibrium chemistry-based computer program (MINEQL+) with experimental results obtained by dosing ferrous salts showed that the product of precipitation is FeS under all operational conditions tested. Regarding the reaction between ferric salts and sulfide species, analysis of thermodynamic data suggested that the dominant product of sulfide oxidation under typical pe/pH conditions prevailing in municipal raw wastewater is SO(4)(2-). However, comparison between sulfide removal in laboratory experiments conducted with multiple samples of raw municipal sewage with a varying composition, and the prediction of MINEQL+ showed the main sulfide oxidation product to be S(0). In order to reduce sulfide in sewage to <0.1 mgS/l a minimal molar ratio of around 1.3 Fe to 1 S should be applied when ferrous salts are used, as compared with a minimal ratio of 0.9 Fe to 1 S required when ferric salts or a mixture of ferrous and ferric salts (at a 2 Fe(III) to 1 Fe(II) ratio) are used. It appears that the high Fe to S(-II) ratios often recommended in practice can be reduced considerably by applying tight in-line control.     

On the economic effects of the text completion interface: empirical analysis of financial markets

Electronic Markets - In financial markets, investment options are relatively fixed but may occasionally change as new securities (tickers) are introduced to the markets. Theory on exploratory...     

Fuzzy-logic optical optimization of mainframe CPU and memory

The allocation of CPU time and memory resources is a familiar problem in organizations with a large number of users and a single mainframe. Usually the amount of resources allocated to a single user is based on the user's own statistics not on the statistics of the entire organization, therefore patterns are not well identified and the allocation system is prodigal. A fuzzy-logic-based algorithm to optimize the CPU and memory distribution among users based on their history is suggested. The algorithm works on heavy and light users separately since they present different patterns to be observed. The result is a set of rules generated by the fuzzy-logic inference engine that will allow the system to use its computing ability in an optimized manner. Test results on data taken from the Faculty of Engineering of Tel Aviv University demonstrate the capabilities of the new algorithm.