Pluripotency factors functionally premark cell-type-restricted enhancers in ES cells.

Enhancers for embryonic stem (ES) cell-expressed genes and lineage-determining factors are characterized by conventional marks of enhancer activation in ES cells1-3, but it remains unclear whether enhancers destined to regulate cell-type-restricted transcription units might also have distinct signatures in ES cells. Here we show that cell-type-restricted enhancers are 'premarked' and activated as transcription units by the binding of one or two ES cell transcription factors, although they do not exhibit traditional enhancer epigenetic marks in ES cells, thus uncovering the initial temporal origins of cell-type-restricted enhancers. This premarking is required for future cell-type-restricted enhancer activity in the differentiated cells, with the strength of the ES cell signature being functionally important for the subsequent robustness of cell-type-restricted enhancer activation. We have experimentally validated this model in macrophage-restricted enhancers and neural precursor cell (NPC)-restricted enhancers using ES cell-derived macrophages or NPCs, edited to contain specific ES cell transcription factor motif deletions. DNA hydroxyl-methylation of enhancers in ES cells, determined by ES cell transcription factors, may serve as a potential molecular memory for subsequent enhancer activation in mature macrophages. These findings suggest that the massive repertoire of cell-type-restricted enhancers are essentially hierarchically and obligatorily premarked by binding of a defining ES cell transcription factor in ES cells, dictating the robustness of enhancer activation in mature cells

Lower Bounds on Charged Higgs Bosons from LEP and the TEVATRON

We point out that charged Higgs bosons can decay into final states different than $\tau^+ \nu_\tau$ and $c \bar{s}$, even when they are light enough to be produced at LEPII or at the Tevatron, through top-quark decays. These additional decay modes are overlooked in ongoing searches even though they alter the existing lower bounds on the mass of charged Higgs bosons that are present in supersymmetric and two Higgs doublets models.Comment: 9 pages, 4 figure

Associated H−^{-} W+^{+} Production in High Energy e+e−e^+e^- Collisions

We study the associated production of charged Higgs bosons with $W$ gauge bosons in high energy $e^+ e^-$ collisions at the one loop level. We present the analytical results and give a detailed discussion for the total cross section predicted in the context of a general Two Higgs Doublet Model (THDM).Comment: Latex, 31 pages, 6 figures, cosmetically improved and one reference adde

Postprocessing for quantum random number generators: entropy evaluation and randomness extraction

Quantum random-number generators (QRNGs) can offer a means to generate information-theoretically provable random numbers, in principle. In practice, unfortunately, the quantum randomness is inevitably mixed with classical randomness due to classical noises. To distill this quantum randomness, one needs to quantify the randomness of the source and apply a randomness extractor. Here, we propose a generic framework for evaluating quantum randomness of real-life QRNGs by min-entropy, and apply it to two different existing quantum random-number systems in the literature. Moreover, we provide a guideline of QRNG data postprocessing for which we implement two information-theoretically provable randomness extractors: Toeplitz-hashing extractor and Trevisan's extractor.Comment: 13 pages, 2 figure

EmLog:Tamper-Resistant System Logging for Constrained Devices with TEEs

Remote mobile and embedded devices are used to deliver increasingly impactful services, such as medical rehabilitation and assistive technologies. Secure system logging is beneficial in these scenarios to aid audit and forensic investigations particularly if devices bring harm to end-users. Logs should be tamper-resistant in storage, during execution, and when retrieved by a trusted remote verifier. In recent years, Trusted Execution Environments (TEEs) have emerged as the go-to root of trust on constrained devices for isolated execution of sensitive applications. Existing TEE-based logging systems, however, focus largely on protecting server-side logs and offer little protection to constrained source devices. In this paper, we introduce EmLog -- a tamper-resistant logging system for constrained devices using the GlobalPlatform TEE. EmLog provides protection against complex software adversaries and offers several additional security properties over past schemes. The system is evaluated across three log datasets using an off-the-shelf ARM development board running an open-source, GlobalPlatform-compliant TEE. On average, EmLog runs with low run-time memory overhead (1MB heap and stack), 430--625 logs/second throughput, and five-times persistent storage overhead versus unprotected logs.Comment: Accepted at the 11th IFIP International Conference on Information Security Theory and Practice (WISTP '17

SPRINT: High-Throughput Robust Distributed Schnorr Signatures

We describe high-throughput threshold protocols with guaranteed output delivery for generating Schnorr-type signatures. The protocols run a single message-independent interactive ephemeral randomness generation procedure (e.g., DKG) followed by a \emph{non-interactive} multi-message signature generation procedure. The protocols offer significant increase in throughput already for as few as ten parties while remaining highly-efficient for many hundreds of parties with thousands of signatures generated per minute (and over 10,000 in normal optimistic case). These protocols extend seamlessly to the dynamic/proactive setting, where each run of the protocol uses a new committee, and they support sub-sampling the committees from among an effectively unbounded number of nodes. The protocols work over a broadcast channel in both synchronous and asynchronous networks. The combination of these features makes our protocols a good match for implementing a signature service over an (asynchronous) public blockchain with many validators, where guaranteed output delivery is an absolute must. In that setting, there is a system-wide public key, where the corresponding secret signature key is distributed among the validators. Clients can submit messages (under suitable controls, e.g. smart contracts), and authorized messages are signed relative to the global public key. Asymptotically, when running with committees of $n$ parties, our protocols can generate $\Omega(n^2)$ signatures per run, while providing resilience against $\Omega(n)$ corrupted nodes, and using broadcast bandwidth of only $O(n^2)$ group elements and scalars. For example, we can sign about $n^2/16$ messages using just under $2n^2$ total bandwidth while supporting resilience against $n/4$ corrupted parties, or sign $n^2/8$ messages using just over $2n^2$ total bandwidth with resilience against $n/5$ corrupted parties. We prove security of our protocols by reduction to the hardness of the discrete logarithm problem in the random-oracle model

Quantum key distribution with delayed privacy amplification and its application to security proof of a two-way deterministic protocol

Privacy amplification (PA) is an essential post-processing step in quantum key distribution (QKD) for removing any information an eavesdropper may have on the final secret key. In this paper, we consider delaying PA of the final key after its use in one-time pad encryption and prove its security. We prove that the security and the key generation rate are not affected by delaying PA. Delaying PA has two applications: it serves as a tool for significantly simplifying the security proof of QKD with a two-way quantum channel, and also it is useful in QKD networks with trusted relays. To illustrate the power of the delayed PA idea, we use it to prove the security of a qubit-based two-way deterministic QKD protocol which uses four states and four encoding operations.Comment: 11 pages, 3 figure

The muon anomalous magnetic moment and a new light gauge boson

It is shown that the 2.6 $\sigma$ discrepancy between the predicted and recently measured value of the anomalous magnetic moment of positive muons could be explained by the existence of a new light gauge boson X with a mass $M_X \leq O(5) GeV$. Phenomenological bounds on the X coupling are discussed.Comment: 7 pages, version to appear in PL

Phenomenology of models with more than two Higgs doublets

We study the most general Multi-Higgs-Doublet Model (MHDM) with Natural Flavor Conservation (NFC). The couplings of a charged scalar $H_i^{\pm}$ to up quarks, down quarks and charged leptons depend on three new complex parameters, $X_i$, $Y_i$ and $Z_i$, respectively. We prove relations among these parameters. We carry out a comprehensive analysis of phenomenological constraints on the couplings of the lightest charged scalar: $X$, $Y$ and $Z$. We find that the general MHDM may differ significantly from its minimal version, the Two-Higgs-Doublet Model (2HDM).Comment: 28 pages, 8 figures available upon request, LaTeX, WIS-94/3/Jan-P

Inert Dark Matter and Strong Electroweak Phase Transition

The main virtue of the Inert Doublet Model (IDM) is that one of its spinless neutral bosons can play the role of Dark Matter. Assuming that the additional sources of CP violation are present in the form of higher dimensional operator(s) we reexamine the possibility that the model parameters for which the right number density of relic particles is predicted are compatible with the first order phase transition that could lead to electroweak baryogenesis. We find, taking into account recent indications from the LHC and the constraints from the electroweak precision data, that for a light DM (40-60 GeV) particle and heavy almost degenerate additional scalars $H^\pm$ and $A^0$ this is indeed possible but the two parameters most important for the strength of the phase transition: the common mass of $H^\pm$ and $A^0$ and the trilinear coupling of the Higgs-like particle to DM are strongly constrained. $H^\pm$ and $A^0$ must weight less than $\sim440$ GeV if the inert minimum is to be the lowest one and the value of the coupling is limited by the XENON 100 data. We stress the important role of the zero temperature part of the potential for the strength of the phase transition.Comment: 15 pages, 5 figures, minor chnges, comment on h-->2gamma adde