The Near-Infrared Spectrograph (NIRSpec) on the James Webb Space Telescope V. Optimal algorithms for planning multi-object spectroscopic observations

We present an overview of the capabilities and key algorithms employed in the so-called eMPT software suite developed for planning scientifically optimized, multi-object spectroscopic (MOS) observations with the Micro-Shutter Array (MSA) of the Near-Infrared Spectrograph (NIRSpec) instrument on board the James Webb Space Telescope (JWST), the first multi-object spectrograph to operate in space. NIRSpec MOS mode is enabled by a programmable MSA, a regular grid of ~250,000 individual apertures that projects to a static, semi-regular pattern of available slits on the sky and makes the planning and optimization of an MSA observation a rather complex task. As such, the eMPT package is offered to the NIRSpec user community as a supplement to the MSA Planning Tool (MPT) included in the STScI Astronomer's Proposal Tool (APT) to assist in the planning of NIRSpec MOS proposals requiring advanced functionality to meet ambitious science goals. The eMPT produces output that can readily be imported and incorporated into the user's observing program within the APT to generate a customized MPT MOS observation. Furthermore, its novel algorithms and modular approach make it highly flexible and customizable, providing users the option to finely control the workflow and even insert their own software modules to tune their MSA slit masks to the particular scientific objectives at hand

Histone Deacetylase Inhibitors Enhance CD4 T Cell Susceptibility to NK Cell Killing but Reduce NK Cell Function

In the search for a cure for HIV-1 infection, histone deacetylase inhibitors (HDACi) are being investigated as activators of latently infected CD4 T cells to promote their targeting by cytotoxic T-lymphocytes (CTL). However, HDACi may also inhibit CTL function, suggesting different immunotherapy approaches may need to be explored. Here, we study the impact of different HDACi on both Natural Killer (NK) and CTL targeting of HIV-1 infected cells. We found HDACi down-regulated HLA class I expression independently of HIV-1 Nef which, without significantly compromising CTL function, led to enhanced targeting by NK cells. HDACi-treated HIV-1-infected CD4 T cells were also more effectively cleared than untreated controls during NK co-culture. However, HDACi impaired NK function, reducing degranulation and killing capacity. Depending on the HDACi and dose, this impairment could counteract the benefit gained by treating infected target cells. These data suggest that following HDACi-induced HLA class I down-regulation NK cells kill HIV-1-infected cells, although HDACi-mediated NK cell inhibition may negate this effect. Our data emphasize the importance of studying the effects of potential interventions on both targets and effectors

The discontinuous Galerkin method for fractional degenerate convection-diffusion equations

We propose and study discontinuous Galerkin methods for strongly degenerate convection-diffusion equations perturbed by a fractional diffusion (L\'evy) operator. We prove various stability estimates along with convergence results toward properly defined (entropy) solutions of linear and nonlinear equations. Finally, the qualitative behavior of solutions of such equations are illustrated through numerical experiments

Patterns and localized structures in bistable semiconductor resonators

We report experiments on spatial switching dynamics and steady state structures of passive nonlinear semiconductor resonators of large Fresnel number. Extended patterns and switching front dynamics are observed and investigated. Evidence of localization of structures is given.Comment: 5 pages with 9 figure

The Inverse S-Box, Non-linear Polynomial Relations and Cryptanalysis of Block Ciphers

Abstract. This paper is motivated by the design of AES. We consider a broader question of cryptanalysis of block ciphers having very good non-linearity and diffusion. Can we expect anyway, to attacks such ciphers, clearly designed to render hopeless the main classical attacks? Recently a lot of attention have been drawn to the existence of multivariate algebraic relations for AES (and other) S-boxes. Then, if the XSL-type algebraic attacks on block ciphers [11] are shown to work well, the answer would be positive. In this paper we show that the answer is certainly positive for many other constructions of ciphers. This is not due to an algebraic attack, but to new types of generalised linear cryptanalysis, highly-nonlinear in flavour. We present several constructions of somewhat special practical block ciphers, seemingly satisfying all the design criteria of AES and using similar S-boxes, and yet being extremely weak. They can be generalised, and evolve into general attacks that can be applied- potentially- to any block cipher. Key Words: block ciphers, AES, Rijndael, interpolation attack on block ciphers, fractional transformations, homographic functions, multivariate equations

Repeated games for eikonal equations, integral curvature flows and non-linear parabolic integro-differential equations

The main purpose of this paper is to approximate several non-local evolution equations by zero-sum repeated games in the spirit of the previous works of Kohn and the second author (2006 and 2009): general fully non-linear parabolic integro-differential equations on the one hand, and the integral curvature flow of an interface (Imbert, 2008) on the other hand. In order to do so, we start by constructing such a game for eikonal equations whose speed has a non-constant sign. This provides a (discrete) deterministic control interpretation of these evolution equations. In all our games, two players choose positions successively, and their final payoff is determined by their positions and additional parameters of choice. Because of the non-locality of the problems approximated, by contrast with local problems, their choices have to "collect" information far from their current position. For integral curvature flows, players choose hypersurfaces in the whole space and positions on these hypersurfaces. For parabolic integro-differential equations, players choose smooth functions on the whole space

Far-Ultraviolet Dust Albedo Measurements in the Upper Scorpius Cloud Using the SPINR Sounding Rocket Experiment

The Spectrograph for Photometric Imaging with Numeric Reconstruction (SPINR) sounding rocket experiment was launched on 2000 August 4 to record far-ultraviolet (912-1450 A) spectral and spatial information for the giant reflection nebula in the Upper Scorpius region. The data were divided into three arbitrary bandpasses (912-1029 A, 1030-1200 A, and 1235-1450 A) for which stellar and nebular flux levels were derived. These flux measurements were used to constrain a radiative transfer model and to determine the dust albedo for the Upper Scorpius region. The resulting albedos were 0.28+/-0.07 for the 912-1029 A bandpass, 0.33+/-0.07 for the 1030-1200 A bandpass, and 0.77+/-0.13 for the 1235-1450 A bandpass