Modular differential equations for characters of RCFT

We discuss methods, based on the theory of vector-valued modular forms, to determine all modular differential equations satisfied by the conformal characters of RCFT; these modular equations are related to the null vector relations of the operator algebra. Besides describing effective algorithmic procedures, we illustrate our methods on an explicit example.Comment: 13 page

Towards the Perfect X-ray Beam Splitter

X-ray free-electron lasers (FEL) deliver ultrabright X-ray pulses, but not the sequences of phase-coherent pulses required for time-domain interferometry and control of quantum states. For conventional split-and-delay schemes to produce such sequences the challenge stems from extreme stability requirements when splitting Angstrom wavelength beams where tiniest path length differences introduce phase jitter. We describe an FEL mode based on selective electron bunch degradation and transverse beam shaping in the accelerator, combined with a self-seeded photon emission scheme. Instead of splitting the photon pulses after their generation by the FEL, we split the electron bunch in the accelerator, prior to photon generation, to obtain phase-locked X-ray pulses with sub-femtosecond duration. Time-domain interferometry becomes possible, enabling the concomitant program of classical and quantum optics experiments with X-rays. The scheme leads to new scientific benefits of cutting-edge FELs with attosecond and/or high-repetition rate capabilities, ranging from the X-ray analog of Fourier transform infrared spectroscopy to damage-free measurements

Regenerative approaches for V/UHTS feeder links: system analysis and on-board complexity reduction

The dramatically increasing demand for high data rates necessitates the proper dimensioning of the feeder links of very or ultra high throughput satellite (V/UHTS) systems. However, because most of the current solutions rely on transparent payloads, the deployment of a very large number of spatially separated ground stations is necessary to support the total system bandwidth by enabling a full reuse of the scarce available uplink bandwidth. This approach has a significant impact on the complexity and the costs of the ground segment infrastructure. Regenerative payloads could be considered to avoid this design bottleneck. By allowing demodulation and decoding on-board the satellite, the favourable link budget conditions of feeder links compared to the user links can be exploited. Using a spectral efficient transmission technique, the number of ground stations required to support a target sum throughput can be notably reduced. Meanwhile, regenerative solutions have until now barely been used in V/UHTS payloads due to their high on-board power consumption. As a consequence, candidate solutions are proposed in this work to overcome this limitation. A non-coherent modulation technique, known as Differential Amplitude Phase Shift Keying (DAPSK), is introduced to avoid on-board carrier synchronization. Moreover, polar codes are considered to minimize the power consumption of the channel decoder. A preliminary analysis of the expected on-board power consumption compared to that of a standard DVB-S2 approach is conducted using available results in the open literature. Link performance is also evaluated via numerical simulations

Specific Heat Study of Non-Fermi Liquid Behavior in CeNi_2Ge_2: Anomalous Peak in Quasi-Particle Density-of-States

To investigate the non-Fermi liquid (NFL) behavior in a nonalloyed system CeNi_2Ge_2, we have measured the temperature and field dependences of the specific heat C on a CeNi_2Ge_2 single crystal. The distinctive temperature dependence of C/T (~a-b*T^(1/2)) is destroyed in almost the same manner for both field directions of B//c-axis and B//a-axis. The overall behavior of C(T,B) and the low-temperature upturn in magnetic susceptibility can be reproduced, assuming an anomalous peak of the quasi-particle-band density-of-states (DOS) at the Fermi energy possessing (epsilon)^(1/2) energy dependence. Absence of residual entropy around T=0 K in B~0 T has been confirmed by the magnetocaloric effect measurements, which are consistent with the present model. The present model can also be applied to the NFL behavior in CeCu_{5.9}Au_{0.1} using a ln(epsilon)-dependent peak in the DOS. Possible origins of the peak in the DOS are discussed.Comment: 4 pages, LaTeX, using jpsj.sty, to be published in J. Phys. Soc. Jpn. 66 No. 10 (1997), 7 figures available at http://494-475.phys.metro-u.ac.jp/ao/ceni2ge2.htm

A Holder Continuous Nowhere Improvable Function with Derivative Singular Distribution

We present a class of functions $\mathcal{K}$ in $C^0(\R)$ which is variant of the Knopp class of nowhere differentiable functions. We derive estimates which establish \mathcal{K} \sub C^{0,\al}(\R) for 0<\al<1 but no $K \in \mathcal{K}$ is pointwise anywhere improvable to C^{0,\be} for any \be>\al. In particular, all $K$'s are nowhere differentiable with derivatives singular distributions. $\mathcal{K}$ furnishes explicit realizations of the functional analytic result of Berezhnoi. Recently, the author and simulteously others laid the foundations of Vector-Valued Calculus of Variations in $L^\infty$ (Katzourakis), of $L^\infty$-Extremal Quasiconformal maps (Capogna and Raich, Katzourakis) and of Optimal Lipschitz Extensions of maps (Sheffield and Smart). The "Euler-Lagrange PDE" of Calculus of Variations in $L^\infty$ is the nonlinear nondivergence form Aronsson PDE with as special case the $\infty$-Laplacian. Using $\mathcal{K}$, we construct singular solutions for these PDEs. In the scalar case, we partially answered the open $C^1$ regularity problem of Viscosity Solutions to Aronsson's PDE (Katzourakis). In the vector case, the solutions can not be rigorously interpreted by existing PDE theories and justify our new theory of Contact solutions for fully nonlinear systems (Katzourakis). Validity of arguments of our new theory and failure of classical approaches both rely on the properties of $\mathcal{K}$.Comment: 5 figures, accepted to SeMA Journal (2012), to appea

Study and implementation of urogenital schistosomiasis elimination in Zanzibar (Unguja and Pemba islands) using an integrated multidisciplinary approach

ABSTRACT: BACKGROUND: Schistosomiasis is a parasitic infection that continues to be a major public health problem in many developing countries being responsible for an estimated burden of at least 1.4 million disability-adjusted life years (DALYs) in Africa alone. However, morbidity due to schistosomiasis has been greatly reduced in some parts of the world, including Zanzibar. The Zanzibar government is now committed to eliminate urogenital schistosomiasis. Over the next 3--5 years, the whole at-risk population will be administered praziquantel (40 mg/kg) biannually. Additionally, snail control and behaviour change interventions will be implemented in selected communities and the impact measured in a randomized intervention trial. METHODS: In this 5-year research study, on both Unguja and Pemba islands, urogenital schistosomiasis will be assessed in 45 communities with urine filtration and reagent strips in 4,500 schoolchildren aged 9--12 years annually, and in 4,500 first-year schoolchildren and 2,250 adults in years 1 and 5. Additionally, from first-year schoolchildren, a finger-prick blood sample will be collected and examined for Schistosoma haematobium infection biomarkers. Changes in prevalence and infection intensity will be assessed annually. Among the 45 communities, 15 were randomized for biannual snail control with niclosamide, in concordance with preventive chemotherapy campaigns. The reduction of Bulinus globosus snail populations and S. haematobium-infected snails will be investigated. In 15 other communities, interventions triggering behaviour change have been designed and will be implemented in collaboration with the community. A change in knowledge, attitudes and practices will be assessed annually through focus group discussions and in-depth interviews with schoolchildren, teachers, parents and community leaders. In all 45 communities, changes in the health system, water and sanitation infrastructure will be annually tracked by standardized questionnaire-interviews with community leaders. Additional issues potentially impacting on study outcomes and all incurring costs will be monitored and recorded. DISCUSSION: Elimination of schistosomiasis has become a priority on the agenda of the Zanzibar government and the international community. Our study will contribute to identifying what, in addition to preventive chemotherapy, needs to be done to prevent, control, and ultimately eliminate schistosomiasis, and to draw lessons for current and future schistosomiasis elimination programmes in Africa and elsewhere.Trial registrationISRCTN4883768

Inelastic Neutron scattering in CeSi_{2-x}Ga_x ferromagnetic Kondo lattice compounds

Inelastic neutron scattering investigation on ferromagnetic Kondo lattice compounds belonging to CeSi_{2-x}Ga_{x}, x = 0.7, 1.0 and 1.3, system is reported. The thermal evolution of the quasielastic response shows that the Kondo interactions dominate over the RKKY interactions with increase in Ga concentration from 0.7 to 1.3. This is related to the increase in k-f hybridization with increasing Ga concentration. The high energy response indicates the ground state to be split by crystal field in all three compounds. Using the experimental results we have calculated the crystal field parameters in all three compounds studied here.Comment: 12 Pages Revtex, 2 eps figures

PlaNet - Photo Geolocation with Convolutional Neural Networks

Is it possible to build a system to determine the location where a photo was taken using just its pixels? In general, the problem seems exceptionally difficult: it is trivial to construct situations where no location can be inferred. Yet images often contain informative cues such as landmarks, weather patterns, vegetation, road markings, and architectural details, which in combination may allow one to determine an approximate location and occasionally an exact location. Websites such as GeoGuessr and View from your Window suggest that humans are relatively good at integrating these cues to geolocate images, especially en-masse. In computer vision, the photo geolocation problem is usually approached using image retrieval methods. In contrast, we pose the problem as one of classification by subdividing the surface of the earth into thousands of multi-scale geographic cells, and train a deep network using millions of geotagged images. While previous approaches only recognize landmarks or perform approximate matching using global image descriptors, our model is able to use and integrate multiple visible cues. We show that the resulting model, called PlaNet, outperforms previous approaches and even attains superhuman levels of accuracy in some cases. Moreover, we extend our model to photo albums by combining it with a long short-term memory (LSTM) architecture. By learning to exploit temporal coherence to geolocate uncertain photos, we demonstrate that this model achieves a 50% performance improvement over the single-image model

Non-equilibrium stochastic dynamics of continuous systems and Bogoliubov generating functionals

Combinatorial harmonic analysis techniques are used to develop new functional analysis methods based on Bogoliubov functionals. Concrete applications of the methods are presented, namely, the study of a non-equilibrium stochastic dynamics of continuous systems.Comment: 37 page