The Strategic Justification for BGP

The Internet consists of many administrative domains, or \emph{Autonomous Systems} (ASes), each owned by an economic entity (Microsoft, AT\&T, The Hebrew University, etc.). The task of ensuring interconnectivity between ASes, known as \emph{interdomain routing}, is currently handled by the \emph{Border Gateway Protocol} (BGP). ASes are self-interested and might be willing to manipulate BGP for their benefit. In this paper we present the strategic justification for using BGP for interdomain routing in today's Internet: We show that, in the realistic Gao-Rexford setting, BGP is immune to almost all forms of rational manipulation by ASes, and can easily be made immune to all such manipulations. The Gao-Rexford setting is said to accurately depict the current commercial relations between ASes in the Internet. Formally, we prove that a slight modification of BGP is incentive-compatible in \emph{ex-post Nash equilibrium}. Moreover, we show that, if a certain reasonable condition holds, then this slightly modified BGP is also \emph{collusion-proof} in ex-post Nash -- i.e., immune to rational manipulations even by \emph{coalitions} of \emph{any} size. Unlike previous works on achieving incentive-compatibility in interdomain routing, our results \emph{do not require any monetary transfer between ASes} (as is the case in practice). We also strengthen the Gao-Rexford constraints by proving that one of the three constraints can actually be enforced by the rationality of ASes if the two other constraints hold.Networks; Ex post Nash; Routing; rational manipulation; Border Gateway Protocol; Dispute Wheel

Interdomain routing and games

We present a game-theoretic model that captures many of the intricacies of \emph{interdomain routing} in today's Internet. In this model, the strategic agents are source nodes located on a network, who aim to send traffic to a unique destination node. The interaction between the agents is dynamic and complex -- asynchronous, sequential, and based on partial information. Best-reply dynamics in this model capture crucial aspects of the only interdomain routing protocol de facto, namely the Border Gateway Protocol (BGP). We study complexity and incentive-related issues in this model. Our main results are showing that in realistic and well-studied settings, BGP is incentive-compatible. I.e., not only does myopic behaviour of all players \emph{converge} to a ``stable'' routing outcome, but no player has motivation to unilaterally deviate from the protocol. Moreover, we show that even \emph{coalitions} of players of \emph{any} size cannot improve their routing outcomes by collaborating. Unlike the vast majority of works in mechanism design, our results do not require any monetary transfers (to or by the agents).Interdomain Routing; Network Games; BGP protocol;

Constitutional Human Duties

Constitutional human duties are simultaneously present and absent. Though many human duties are set forth in many constitutions throughout the entire world, modern scholarship has almost entirely excluded them from legal conceptualization. Liberalism shifted the spotlight to the individual, as an autonomous independent unit, while abandoning society. Furthermore, there is a tendency to frame constitutional human duties as “constitutional interests.” This Article suggests an innovative comparative analysis of constitutional human duties. Founded on that analysis, this Article develops a novel typology through which the characteristics of constitutional human duties are examined. The implications of various constitutional duties are explored in accordance with the proposed typology. This Article further argues that, notwithstanding the differences between various constitutional human duties, all the duties share core characteristics and implications. Finally, this Article proposes that the constitutionalization of human duties is justified as long as their inclusion in the Constitution is essential for protecting fundamental constitutional values

Diameter Variability of Rotary Files and Their Corresponding Gutta-Percha Cones Using Laser Scan Micrometre

Introduction: Manufacturers offer gutta-percha (GP) cones matched with different sizes of endodontic files as an attempt to simplify the obturation process and create a tight seal in the canal. The purpose of this study was to evaluate whether intra-manufacture GP diameters matched the diameters of their corresponding files at different levels using laser micrometre. Methods and Materials: Twenty files and corresponding GP master cones of Reciproc R40 (40/0.06) (VDW, Munich, Germany), WaveOne Large (40/0.08) (Dentsply Maillefer, Ballaigues, Switzerland), ProTaper F3 (30/0.09) (Dentsply Maillefer, Ballaigues, Switzerland), and Mtwo 40/0.06 (VDW, Munich, Germany) were examined using laser micrometre (LSM 6000 by Mitutoyo, Japan) with accuracy of 1 nm to establish their actual diameter at D0, D1, D3 and D6. The data was analysed using the independent t-test. The differences were considered at 0.05. Results: The diameter of GP master cones was significantly larger than that of the corresponding files at all levels in all brands. ProTaper GP diameter was closest to the file diameter at D1 (GP=0.35, File=0.35 mm), and D3 (GP=0.48, File=0.49). Conclusion: Within the same manufacturer, GP cone diameters do not match the diameters of their corresponding files. Clinicians are advised to use a GP gauge to cut the tip so as to appropriate the diameter from a smaller sized GP cone.Keywords: Diameter; Gutta-Percha; Root Canal; Rotary File; Size 

On flow magnitude and field-flow alignment at Earth's core surface

We present a method to estimate the typical magnitude of flow close to Earth's core surface based on observational knowledge of the geomagnetic main field (MF) and its secular variation (SV), together with prior information concerning field-flow alignment gleaned from numerical dynamo models. An expression linking the core surface flow magnitude to spherical harmonic spectra of the MF and SV is derived from the magnetic induction equation. This involves the angle γ between the flow and the horizontal gradient of the radial field. We study γ in a suite of numerical dynamo models and discuss the physical mechanisms that control it. Horizontal flow is observed to approximately follow contours of the radial field close to high-latitude flux bundles, while more efficient induction occurs at lower latitudes where predominantly zonal flows are often perpendicular to contours of the radial field. We show that the amount of field-flow alignment depends primarily on a magnetic modified Rayleigh number Raη=αg0ΔTD/ηΩ, which measures the vigour of convective driving relative to the strength of magnetic dissipation. Synthetic tests of the flow magnitude estimation scheme are encouraging, with results differing from true values by less than 8 per cent. Application to a high-quality geomagnetic field model based on satellite observations (the xCHAOS model in epoch 2004.0) leads to a flow magnitude estimate of 11-14 km yr−1, in accordance with previous estimates. When applied to the historical geomagnetic field model gufm1 for the interval 1840.0-1990.0, the method predicts temporal variations in flow magnitude similar to those found in earlier studies. The calculations rely primarily on knowledge of the MF and SV spectra; by extrapolating these beyond observed scales the influence of small scales on flow magnitude estimates is assessed. Exploring three possible spectral extrapolations we find that the magnitude of the core surface flow, including small scales, is likely less than 50 km yr−

Alias-Free Convnets: Fractional Shift Invariance via Polynomial Activations

Although CNNs are believed to be invariant to translations, recent works have shown this is not the case, due to aliasing effects that stem from downsampling layers. The existing architectural solutions to prevent aliasing are partial since they do not solve these effects, that originate in non-linearities. We propose an extended anti-aliasing method that tackles both downsampling and non-linear layers, thus creating truly alias-free, shift-invariant CNNs. We show that the presented model is invariant to integer as well as fractional (i.e., sub-pixel) translations, thus outperforming other shift-invariant methods in terms of robustness to adversarial translations.Comment: The paper was accepted to CVPR 2023. Our code is available at https://github.com/hmichaeli/alias_free_convnets

The Intra-Manufacture Diameter Variability of Rotary Files and Their Corresponding Gutta-Percha Cones Using Laser Scan Micrometer

Introduction: As an attempt to simplify the obturation process and create a tight seal, manufacturers offer gutta-percha (GP) cones matching different sizes of endodontic files. The purpose of this study was to evaluate whether intra-manufacture GP diameters matched the diameters of their corresponding files at different horizontal levels of the canal. Methods and Materials: Twenty files and corresponding GP master cones of Reciproc R 40/0.08 (VDW, Munich, Germany), WaveOne Large (40/0.08) (Dentsply Maillefer, Ballaigues, Switzerland), ProTaper F3 (30/0.09) (Dentsply Maillefer, Ballaigues, Switzerland), and Mtwo (40/0.06) (VDW, Munich, Germany) were examined using laser micrometer (LSM 6000 by Mitutoyo, Japan) with accuracy of 1 nm to establish their actual diameter at D0, D1, D3 and D6. Data were analysed using the independent t-test. The differences were considered as significant for P<0.05. Results: The diameter of GP master cones was significantly larger than the corresponding files at all levels with all the above brands. ProTaper GP diameter were closest to the file diameter at D1 (GP=0.35, File=0.35 mm), and D3 (GP=0.48, file=0.49). Conclusion: This in vitro study showed that within the same manufacturer GP cone diameters do not match the diameters of their corresponding files.Keywords: Diameter; Gutta-percha Cone; Laser Scan Micrometer; Rotary File; Tape

Tests of core flow imaging methods with numerical dynamos

We test the quality of a new core flow imaging method that incorporates constraints on flow helicity, using synthetic magnetic secular variation data from 3-D self-consistent numerical dynamo models. Comparison with the dynamo model flows reveals that our imaging method delineates most of the main large-scale flow features, both in pattern and magnitude. The dynamo model flows are characterized by high-latitude vortices, some equatorial symmetry, columnar convection and a significant amount of flow along radial magnetic field contours. Our inversion method correctly images these aspects of the flows. The correlation coefficient between the dynamo velocity and the imaged velocity exceeds 0.5 in cases with large-scale flow and magnetic field pattern, but degrades substantially in more complex cases when the scale of the secular variation is small. The magnitude of the imaged velocity depends on the a priori-assumed ratio of tangential divergence to radial vorticity k, in some resemblance to the damping parameter in spectral methods, although with our method the misfit is insensitive to k-values. Including tangential magnetic diffusion in core flow inversion improves the quality of the imaged velocity patte

Comparative metagenomic analyses reveal viral-induced shifts of host metabolism towards nucleotide biosynthesis

BACKGROUND: Viral genomes often contain metabolic genes that were acquired from host genomes (auxiliary genes). It is assumed that these genes are fixed in viral genomes as a result of a selective force, favoring viruses that acquire specific metabolic functions. While many individual auxiliary genes were observed in viral genomes and metagenomes, there is great importance in investigating the abundance of auxiliary genes and metabolic functions in the marine environment towards a better understanding of their role in promoting viral reproduction. RESULTS: In this study, we searched for enriched viral auxiliary genes and mapped them to metabolic pathways. To initially identify enriched auxiliary genes, we analyzed metagenomic microbial reads from the Global Ocean Survey (GOS) dataset that were characterized as viral, as well as marine virome and microbiome datasets from the Line Islands. Viral-enriched genes were mapped to a “global metabolism network” that comprises all KEGG metabolic pathways. Our analysis of the viral-enriched pathways revealed that purine and pyrimidine metabolism pathways are among the most enriched pathways. Moreover, many other viral-enriched metabolic pathways were found to be closely associated with the purine and pyrimidine metabolism pathways. Furthermore, we observed that sequential reactions are promoted in pathways having a high proportion of enriched genes. In addition, these enriched genes were found to be of modular nature, participating in several pathways. CONCLUSIONS: Our naïve metagenomic analyses strongly support the well-established notion that viral auxiliary genes promote viral replication via both degradation of host DNA and RNA as well as a shift of the host metabolism towards nucleotide biosynthesis, clearly indicating that comparative metagenomics can be used to understand different environments and systems without prior knowledge of pathways involved