Elastic response of filamentous networks with compliant crosslinks

Experiments have shown that elasticity of disordered filamentous networks with compliant crosslinks is very different from networks with rigid crosslinks. Here, we model and analyze filamentous networks as a collection of randomly oriented rigid filaments connected to each other by flexible crosslinks that are modeled as worm-like chains. For relatively large extensions we allow for enthalpic stretching of crosslinks' backbones. We show that for sufficiently high crosslink density, the network linear elastic response is affine on the scale of the filaments' length. The nonlinear regime can become highly nonaffine and is characterized by a divergence of the elastic modulus at finite strain. In contrast to the prior predictions, we do not find an asymptotic regime in which the differential elastic modulus scales linearly with the stress, although an approximate linear dependence can be seen in a transition from entropic to enthalpic regimes. We discuss our results in light of the recent experiments.Comment: 10 pages, 11 figure

Giving Voice to Language: Basque Language Activism and the Politics of Education in France, 1969-1994

Over the past several decades there has been a wellspring of political debate in Europe regarding the rights of linguistic minorities in education. Perhaps nowhere has this transnational debate sparked more controversy than in France where the notion of linguistic rights has been negatively construed by many political authorities as antithetical to the republican model of universal public education. Despite such enmity a host of ethnolinguistic activists in France have been laboring for decades to transform education from a site of exclusion into a vehicle of empowerment. In this dissertation I explore the mobilization dynamics that characterized a minority language schooling initiative within the French Basque Country from 1969 to 1994. Drawing on qualitative case study data, I pay particular attention to the struggles, strategies and successes of Basque language activists affiliated with a community-based schooling association known as 'Seaska'. Building on social movement theory, I argue that Seaska gradually accrued the support of reluctant policy-makers by mobilizing an influential repertoire of discursive, organizational and performative strategies. Throughout my discussion I show how these strategic practices allowed Seaska to cope with an enduring tide of political opposition, seize upon several windows of political opportunity and gain increasing levels of recognition within the political arena. By way of conclusion I consider future avenues for conducting comparative research on minority language activism in educational settings beyond the French Basque context

Direct evidence for the magnetic ordering of Nd ions in NdMn2_2Si2_2 and NdMn2_2Ge2_2 by high resolution inelastic neutron scattering

We have investigated the low energy nuclear spin excitations in NdMn$_2$Si$_2$ and NdMn$_2$Ge$_2$ by high resolution inelastic neutron scattering. Previous neutron diffraction investigations gave ambiguous results about Nd magnetic ordering at low temperatures. The present element-specific technique gave direct evidence for the magnetic ordering of Nd ions. We found considerable difference in the process of the Nd magnetic ordering at low temperature in NdMn$_2$Si$_2$ and NdMn$_2$Ge$_2$. Our results are consistent with those of magnetization and recent neutron diffraction measurements

Direct evidence for the magnetic ordering of Nd ions in NdFeAsO by high resolution inelastic neutron scattering

We investigated the low energy excitations in the parent compound NdFeAsO of the Fe-pnictide superconductor in the $\mu$eV range by a back scattering neutron spectrometer. The energy scans on a powder NdFeAsO sample revealed inelastic peaks at E = 1.600 $\pm 0.003 \mu$eV at T = 0.055 K on both energy gain and energy loss sides. The inelastic peaks move gradually towards lower energy with increasing temperature and finally merge with the elastic peak at about 6 K. We interpret the inelastic peaks to be due to the transition between hyperfine-split nuclear level of the $^{143}$Nd and $^{145}$Nd isotopes with spin $I = 7/2$. The hyperfine field is produced by the ordering of the electronic magnetic moment of Nd at low temperature and thus the present investigation gives direct evidence of the ordering of the Nd magnetic sublattice of NdFeAsO at low temperature

Quantum key distribution using non-classical photon number correlations in macroscopic light pulses

We propose a new scheme for quantum key distribution using macroscopic non-classical pulses of light having of the order 10^6 photons per pulse. Sub-shot-noise quantum correlation between the two polarization modes in a pulse gives the necessary sensitivity to eavesdropping that ensures the security of the protocol. We consider pulses of two-mode squeezed light generated by a type-II seeded parametric amplification process. We analyze the security of the system in terms of the effect of an eavesdropper on the bit error rates for the legitimate parties in the key distribution system. We also consider the effects of imperfect detectors and lossy channels on the security of the scheme.Comment: Modifications:added new eavesdropping attack, added more references Submitted to Physical Review A [email protected]

Artifacts - Anycast Agility: Network Playbooks to Fight DDoS

In this document, we provide datasets and software tools related to our paper “Anycast Agility: Network Playbooks to Fight DDoS”. Our artifact contains several datasets generated from our anycast experiments and analysis. Our datasets provide a snapshot of the results that we generated during our experiments. Some of our experimental results are dependent on the current state of the network interconnections and policies. However, due to the anycast stability, we expect to get similar results if we redo the experiments now. Our published datasets support our key results and are publicly available. We also provide tools and scripts that can be useful for other researchers. We provide datasets and tools for measuring anycast agility against DDoS. Our datasets are available upon request. We provide datasets about the traffic distribution after BGP changes in testbeds, attack data from a DNS root server and from the Dutch National Scrubbing Center, other data related to anycast catchment stability, and other supporting data for our software tools. We provide codes for traffic estimation, for reproducing experiments, and for parsing the collected data.This work is supported, in part, by the DHS HSARPA Cyber Security Division via contract number HSHQDC-17-R-B0004-TTA.02-0006-I and Netherlands Organisation for scientific research (4019020199)