Understanding the Transition between High School and College Mathematics and Science

Mathematics and science education is gaining increasing recognition as key for the well-being of individuals and society. Accordingly, the transition from high school to college is particularly important to ensure that students are prepared for college mathematics and science. The goal of this study was to understand how high school mathematics and science course-taking related to performance in college. Specifically, the study employed a nonparametric regression method to examine the relationship between high school mathematics and science courses, and academic performance in college mathematics and science courses. The results provide some evidence pertaining to the positive benefits from high school course-taking. Namely, students who completed high school trigonometry and lab-based chemistry tended to earn higher grades in college algebra and general chemistry, respectively. However, there was also evidence that high school coursework in biology and physics did not improve course performance in general biology and college physics beyond standardized test scores. Interestingly, students who completed high school calculus earned better grades in general biology. The implications of the findings are discussed for high school curriculum and alignment in standards between high schools and colleges

Thermal conductivity in harmonic lattices with random collisions

We review recent rigorous mathematical results about the macroscopic behaviour of harmonic chains with the dynamics perturbed by a random exchange of velocities between nearest neighbor particles. The random exchange models the effects of nonlinearities of anharmonic chains and the resulting dynamics have similar macroscopic behaviour. In particular there is a superdiffusion of energy for unpinned acoustic chains. The corresponding evolution of the temperature profile is governed by a fractional heat equation. In non-acoustic chains we have normal diffusivity, even if momentum is conserved.Comment: Review paper, to appear in the Springer Lecture Notes in Physics volume "Thermal transport in low dimensions: from statistical physics to nanoscale heat transfer" (S. Lepri ed.

Hydrodynamic limit for the velocity flip model

We study the diffusive scaling limit for a chain of $N$ coupled oscillators. In order to provide the system with good ergodic properties, we perturb the Hamiltonian dynamics with random flips of velocities, so that the energy is locally conserved. We derive the hydrodynamic equations by estimating the relative entropy with respect to the local equilibrium state modified by a correction term

LCC analysis for glued laminated timber components exposed in external

The aim of the experimentation is to characterize the performances of glued laminated timber components exposed to atmospheric agents, in the light of the concept of Life Cycle Cost, particularly emphasized in the Italian new legislation on public works. In fact, it could be seen that the design of the construction details and the initial characteristics of glue laminated timber components, require a particular attention to avoid errors that may undermine the possibility to perform the structural functions for which, above all, this material it is dedicated. The experimentation consisted of a series of tests aimed to identify the performance of glued laminated timber beams taken in site, after a work executed some years ago on a theatre built in Roman era, and to compare them with similarly manufactured new elements. The tests performed were thermography, ultrasound, Wood-Pecker penetrometer, mechanical characterization. The results will be used to begin setting limits and conditions for outdoor use of glue laminated timber, and assume a reliable life cycle, and consequently identify the most appropriate maintenance strategy for the LCC

Thermal conductivity of the Toda lattice with conservative noise

We study the thermal conductivity of the one dimensional Toda lattice perturbed by a stochastic dynamics preserving energy and momentum. The strength of the stochastic noise is controlled by a parameter $\gamma$. We show that heat transport is anomalous, and that the thermal conductivity diverges with the length $n$ of the chain according to $\kappa(n) \sim n^\alpha$, with $0 < \alpha \leq 1/2$. In particular, the ballistic heat conduction of the unperturbed Toda chain is destroyed. Besides, the exponent $\alpha$ of the divergence depends on $\gamma$

Empirical assessment of the effort needed to attack programs protected with client/server code splitting

Context. Code hardening is meant to fight malicious tampering with sensitive code executed on client hosts. Code splitting is a hardening technique that moves selected chunks of code from client to server. Although widely adopted, the effective benefits of code splitting are not fully understood and thoroughly assessed. Objective. The objective of this work is to compare non protected code vs. code splitting protected code, considering two levels of the chunk size parameter, in order to assess the effectiveness of the protection - in terms of both attack time and success rate - and to understand the attack strategy and process used to overcome the protection. Method. We conducted an experiment with master students performing attack tasks on a small application hardened with different levels of protection. Students carried out their task working at the source code level. Results. We observed a statistically significant effect of code splitting on the attack success rate that, on the average, was reduced from 89% with unprotected clear code to 52% with the most effective protection. The protection variant that moved some small-sized code chunks turned out to be more effective than the alternative moving fewer but larger chunks. Different strategies were identified yielding different success rates. Moreover, we discovered that successful attacks exhibited different process w.r.t. failed ones.Conclusions We found empirical evidence of the effect of code splitting, assessed the relative magnitude, and evaluated the influence of the chunk size parameter. Moreover, we extracted the process used to overcome such obfuscation technique

Fluctuations in Hadronic and Nuclear Collisions

We investigate several fluctuation effects in high-energy hadronic and nuclear collisions through the analysis of different observables. To introduce fluctuations in the initial stage of collisions, we use the Interacting Gluon Model (IGM) modified by the inclusion of the impact parameter. The inelasticity and leading-particle distributions follow directly from this model. The fluctuation effects on rapidity distributions are then studied by using Landau's Hydrodynamic Model in one dimension. To investigate further the effects of the multiplicity fluctuation, we use the Longitudinal Phase-Space Model, with the multiplicity distribution calculated within the hydrodynamic model, and the initial conditions given by the IGM. Forward-backward correlation is obtained in this way.Comment: 22 pages, RevTex, 8 figures (included); Invited paper to the special issue of Foundation of Physics dedicated to Mikio Namiki's 70th. birthda