@inproceedings{18332, abstract = {Presented here is a generalization of the modified relative Newton method, recently proposed in [1] for quasi-maximum likelihood blind source separation. Special structure of the Hessian matrix allows to perform block-coordinate Newton descent, which significantly reduces the algorithm computational complexity and boosts its performance. Simulations based on artificial and real data show that the separation quality using the proposed algorithm outperforms other accepted blind source separation methods.}, author = {Bronstein, Alexander and Bronstein, Michael M. and Zibulevsky, Michael}, booktitle = {5th International Conference on Independent Component Analysis and Blind Signal Separation}, isbn = {9783540230564}, issn = {1611-3349}, location = {Granada, Spain}, pages = {406–413}, publisher = {Springer Nature}, title = {{Blind source separation using the block-coordinate relative Newton method}}, doi = {10.1007/978-3-540-30110-3_52}, volume = {3195}, year = {2004}, } @inproceedings{18333, abstract = {The relative Newton algorithm, previously proposed for quasi maximum likelihood blind source separation and blind deconvolution of one-dimensional signals is generalized for blind deconvolution of images. Smooth approximation of the absolute value is used in modelling the log probability density function, which is suitable for sparse sources. We propose a method of sparsification, which allows blind deconvolution of sources with arbitrary distribution, and show how to find optimal sparsifying transformations by training.}, author = {Bronstein, Alexander and Bronstein, Michael M. and Zibulevsky, Michael and Zeevi, Yehoshua Y.}, booktitle = {5th International Conference on Independent Component Analysis and Blind Signal Separation}, isbn = {9783540230564}, issn = {1611-3349}, location = {Granada, Spain}, pages = {500--507}, publisher = {Springer Nature}, title = {{Optimal sparse representations for blind deconvolution of images}}, doi = {10.1007/978-3-540-30110-3_64}, volume = {3195}, year = {2004}, } @inproceedings{18334, abstract = {We propose a relative optimization framework for quasi maximum likelihood blind deconvolution and the relative Newton method as its particular instance. Special Hessian structure allows its fast approximate construction and inversion with complexity comparable to that of gradient methods. The use of rational IIR restoration kernels provides a richer family of filters than the traditionally used FIR kernels. Smoothed absolute value and the smoothed deadzone functions allow accurate and robust deconvolution of super- and sub-Gaussian sources, respectively. Simulation results demonstrate the efficiency of the proposed methods.}, author = {Bronstein, Alexander and Bronstein, Michael M. and Zibulevsky, Michael}, booktitle = {5th International Conference on Independent Component Analysis and Blind Signal Separation}, isbn = {9783540230564}, issn = {1611-3349}, location = {Granada, Spain}, pages = {554–561}, publisher = {Springer Nature}, title = {{Blind deconvolution using the relative Newton method}}, doi = {10.1007/978-3-540-30110-3_71}, volume = {3195}, year = {2004}, } @inproceedings{18335, abstract = {Blind deconvolution is considered as a problem of quasi maximum likelihood (QML) estimation of the restoration kernel. Simple closed-form expressions for the asymptotic estimation error are derived. The asymptotic performance bounds coincide with the Cramér-Rao bounds, when the true ML estimator is used. Conditions for asymptotic stability of the QML estimator are derived. Special cases when the estimator is super-efficient are discussed.}, author = {Bronstein, Alexander and Bronstein, Michael M. and Zibulevsky, Michael and Zeevi, Yehoshua Y.}, booktitle = {Proceedings of the 5th International Conference on Independent Component Analysis and Blind Signal Separation}, isbn = {9783540230564}, issn = {0302-9743}, location = {Granada, Spain}, pages = {677–684}, publisher = {Springer Nature}, title = {{QML blind deconvolution: Asymptotic analysis}}, doi = {10.1007/978-3-540-30110-3_86}, volume = {3195}, year = {2004}, } @article{18368, abstract = {Presented here is a block-coordinate version of the relative Newton method, recently proposed for quasi-maximum likelihood blind source separation. Special structure of the Hessian matrix allows performing block-coordinate Newton descent efficiently. Simulations show that typically our method converges in near constant number of iterations (order of 10) independently of the problem size.}, author = {Bronstein, Alexander and Bronstein, Michael M and Zibulevsky, Michael}, issn = {0165-1684}, journal = {Signal Processing}, number = {8}, pages = {1447--1459}, publisher = {Elsevier}, title = {{Blind source separation using block-coordinate relative Newton method}}, doi = {10.1016/j.sigpro.2004.05.019}, volume = {84}, year = {2004}, } @inproceedings{18396, abstract = {We discuss the synthesis between the 3D and the 2D data in three-dimensional face recognition. We show how to compensate for the illumination and racial expressions using the 3D facial geometry and present the approach of canonical images, which allows us to incorporate geometric information into standard face recognition approaches.}, author = {Bronstein, Alexander and Bronstein, M.M. and Gordon, E. and Kimmel, R.}, booktitle = {2004 International Conference on Image Processing}, isbn = {0780385543}, issn = {1522-4880}, location = {Singapore, Singapore}, publisher = {IEEE}, title = {{Fusion of 2D and 3D data in three-dimensional face recognition}}, doi = {10.1109/icip.2004.1418696}, year = {2004}, } @inbook{18739, abstract = {The first massive astrophysical black holes likely formed at high redshifts (z≳ 10) at the centers of low mass (~ 106 M⊙) dark matter concentrations. These black holes grow by mergers and gas accretion, evolve into the population of bright quasars observed at lower redshifts, and eventually leave the supermassive black hole remnants that are ubiquitous at the centers of galaxies in the nearby universe. The astrophysical processes responsible for the formation of the earliest seed black holes are poorly understood. The purpose of this review is threefold: (1) to describe theoretical expectations for the formation and growth of the earliest black holes within the general paradigm of hierarchical cold dark matter cosmologies, (2) to summarize several relevant recent observations that have implications for the formation of the earliest black holes, and (3) to look into the future and assess the power of forthcoming observations to probe the physics of the first active galactic nuclei.}, author = {Haiman, Zoltán and Quataert, Eliot}, booktitle = {Supermassive Black Holes in the Distant Universe}, isbn = {9789048166626}, issn = {0067-0057}, pages = {147--185}, publisher = {Springer Nature}, title = {{The Formation and Evolution of the First Massive Black Holes}}, doi = {10.1007/978-1-4020-2471-9_5}, volume = {308}, year = {2004}, } @article{12658, abstract = {[1] During the ablation period 2001 a glaciometeorological experiment was carried out on Haut Glacier d'Arolla, Switzerland. Five meteorological stations were installed on the glacier, and one permanent automatic weather station in the glacier foreland. The altitudes of the stations ranged between 2500 and 3000 m a.s.l., and they were in operation from end of May to beginning of September 2001. The spatial arrangement of the stations and temporal duration of the measurements generated a unique data set enabling the analysis of the spatial and temporal variability of the meteorological variables across an alpine glacier. All measurements were taken at a nominal height of 2 m, and hourly averages were derived for the analysis. The wind regime was dominated by the glacier wind (mean value 2.8 m s−1) but due to erosion by the synoptic gradient wind, occasionally the wind would blow up the valley. A slight decrease in mean 2 m air temperatures with altitude was found, however the 2 m air temperature gradient varied greatly and frequently changed its sign. Mean relative humidity was 71% and exhibited limited spatial variation. Mean incoming shortwave radiation and albedo both generally increased with elevation. The different components of shortwave radiation are quantified with a parameterization scheme. Resulting spatial variations are mainly due to horizon obstruction and reflections from surrounding slopes, i.e., topography. The effect of clouds accounts for a loss of 30% of the extraterrestrial flux. Albedos derived from a Landsat TM image of 30 July show remarkably constant values, in the range 0.49 to 0.50, across snow covered parts of the glacier, while albedo is highly spatially variable below the zone of continuous snow cover. These results are verified with ground measurements and compared with parameterized albedo. Mean longwave radiative fluxes decreased with elevation due to lower air temperatures and the effect of upper hemisphere slopes. It is shown through parameterization that this effect would even be more pronounced without the effect of clouds. Results are discussed with respect to a similar study which has been carried out on Pasterze Glacier (Austria). The presented algorithms for interpolating, parameterizing and simulating variables and parameters in alpine regions are integrated in the software package AMUNDSEN which is freely available to be adapted and further developed by the community.}, author = {Strasser, Ulrich and Corripio, Javier and Pellicciotti, Francesca and Burlando, Paolo and Brock, Ben and Funk, Martin}, issn = {0148-0227}, journal = {Journal of Geophysical Research: Atmospheres}, keywords = {Paleontology, Space and Planetary Science, Earth and Planetary Sciences (miscellaneous), Atmospheric Science, Earth-Surface Processes, Geochemistry and Petrology, Soil Science, Water Science and Technology, Ecology, Aquatic Science, Forestry, Oceanography, Geophysics}, number = {D3}, publisher = {American Geophysical Union}, title = {{Spatial and temporal variability of meteorological variables at Haut Glacier d'Arolla (Switzerland) during the ablation season 2001: Measurements and simulations}}, doi = {10.1029/2003jd003973}, volume = {109}, year = {2004}, } @article{18742, abstract = {Recent improved determinations of the mass density ρBH of supermassive black holes (SMBHs) in the local universe have allowed accurate comparisons of ρBH with the amount of light received from past quasar activity. These comparisons support the notion that local SMBHs are "dead quasars" and yield a value epsilon ≳ 0.1 for the average radiative efficiency of cosmic SMBH accretion. BH coalescences may represent an important component of the quasar mass assembly and yet not produce any observable electromagnetic signature. Therefore, ignoring gravitational wave (GW) emission during such coalescences, which reduces the amount of mass locked into remnant BHs, results in an overestimate of epsilon. Here we put constraints on the magnitude of this bias. We calculate the cumulative mass loss to GWs experienced by a representative population of BHs during repeated cosmological mergers, using loss prescriptions based on detailed general relativistic calculations. Despite the possibly large number of mergers in the assembly history of each individual SMBH, we find that near-equal mass mergers are rare; therefore, the cumulative loss is likely to be modest, amounting at most to a 20% increase in the inferred epsilon value. Thus, recent estimates of epsilon ≳ 0.1 appear robust. The space interferometer LISA should provide empirical constraints on the dark side of quasar evolution by measuring the masses and rates of coalescence of massive BHs to cosmological distances.}, author = {Menou, Kristen and Haiman, Zoltán}, issn = {1538-4357}, journal = {The Astrophysical Journal}, number = {1}, pages = {130--134}, publisher = {American Astronomical Society}, title = {{On the dark side of quasar evolution}}, doi = {10.1086/423951}, volume = {615}, year = {2004}, } @article{1963, abstract = {The mechanism coupling electron transfer and proton pumping in respiratory complex I (NADH-ubiquinone oxidoreductase) has not been established, but it has been suggested that it involves conformational changes. Here, the influence of substrates on the conformation of purified complex I from Escherichia coli was studied by cross-linking and electron microscopy. When a zero-length cross-linking reagent was used, the presence of NAD(P)H, in contrast to that of NAD+, prevented the formation of cross-links between the hydrophilic subunits of the complex, including NuoB, NuoI, and NuoCD. Comparisons using different cross-linkers suggested that NuoB, which is likely to coordinate the key iron-sulfur cluster N2, is the most mobile subunit. The presence of NAD(P)H led also to enhanced proteolysis of subunit NuoG. These data indicate that upon NAD(P)H binding, the peripheral arm of the complex adopts a more open conformation, with increased distances between subunits. Single particle analysis showed the nature of this conformational change. The enzyme retains its L-shape in the presence of NADH, but exhibits a significantly more open or expanded structure both in the peripheral arm and, unexpectedly, in the membrane domain also.}, author = {Mamedova, Aygun A and Holt, Peter J and Carroll, Joe D and Leonid Sazanov}, journal = {Journal of Biological Chemistry}, number = {22}, pages = {23830 -- 23836}, publisher = {American Society for Biochemistry and Molecular Biology}, title = {{Substrate-induced conformational change in bacterial complex I}}, doi = {10.1074/jbc.M401539200}, volume = {279}, year = {2004}, } @article{209, author = {Timothy Browning and Heath-Brown, Roger}, journal = {Inventiones Mathematicae}, number = {3}, pages = {553 -- 573}, publisher = {Unknown}, title = {{Equal sums of three powers}}, doi = {10.1007/s00222-004-0360-9}, volume = {157}, year = {2004}, } @article{2308, abstract = {It is widely believed that the inflammatory events mediated by microglial activation contribute to several neurodegenerative processes. Alzheimer's disease, for example, is characterized by an accumulation of β-amyloid protein (Aβ) in neuritic plaques that are infiltrated by reactive microglia and astrocytes. Although Aβ and its fragment 25-35 exert a direct toxic effect on neurons, they also activate microglia. Microglial activation is accompanied by morphological changes, cell proliferation, and release of various cytokines and growth factors. A number of scientific reports suggest that the increased proliferation of microglial cells is dependent on ionic membrane currents and in particular on chloride conductances. An unusual chloride ion channel known to be associated with macrophage activation is the chloride intracellular channel-1 (CLIC1). Here we show that Aβ stimulation of neonatal rat microglia specifically leads to the increase in CLIC1 protein and to the functional expression of CLIC1 chloride conductance, both barely detectable on the plasma membrane of quiescent cells. CLIC1 protein expression in microglia increases after 24 hr of incubation with Aβ, simultaneously with the production of reactive nitrogen intermediates and of tumor necrosis factor-α (TNF-α). We demonstrate that reducing CLIC1 chloride conductance by a specific blocker [IAA-94 (R(+)-[(6,7-dichloro-2-cyclopentyl-2,3-dihydro-2-methyl-1-oxo-1H-inden-5yl)-oxy] acetic acid)] prevents neuronal apoptosis in neurons cocultured with Aβ-treated microglia. Furthermore, we show that small interfering RNAs used to knock down CLIC1 expression prevent TNF-α release induced by Aβ stimulation. These results provide a direct link between Aβ-induced microglial activation and CLIC1 functional expression.}, author = {Gaia Novarino and Fabrizi, Cinzia and Tonini, Raffaella and Denti, Michela A and Malchiodi, Albedi F and Lauro, Giuliana M and Sacchetti, Benedetto and Paradisi, Silvia and Ferroni, Arnaldo and Curmi, Paul M G and Breit, Samuel N and Mazzanti, Michele}, journal = {Journal of Neuroscience}, number = {23}, pages = {5322 -- 5330}, publisher = {Society for Neuroscience}, title = {{Involvement of the intracellular ion channel CLIC1 in microglia-mediated β-amyloid-induced neurotoxicity}}, doi = {10.1523/JNEUROSCI.1170-04.2004}, volume = {24}, year = {2004}, } @article{2355, abstract = {The BMV conjecture for traces, which states that Tr exp(A - λB) is the Laplace transform of a positive measure, is shown to be equivalent to two other statements: (i) The polynomial λ → Tr(A + λB) p has only non-negative coefficients for all A, B ≥ 0, p ∈ ℕ and (ii) λ → Tr(A + λB)-p is the Laplace transform of a positive measure for A, B ≥ 0, p > 0.}, author = {Lieb, Élliott H and Robert Seiringer}, journal = {Journal of Statistical Physics}, number = {1-2}, pages = {185 -- 190}, publisher = {Springer}, title = {{ Equivalent forms of the Bessis-Moussa-Villani conjecture}}, doi = {10.1023/B:JOSS.0000019811.15510.27}, volume = {115}, year = {2004}, } @article{2356, abstract = {Recent experimental and theoretical work has shown that there are conditions in which a trapped, low-density Bose gas behaves like the one-dimensional delta-function Bose gas solved years ago by Lieb and Liniger. This is an intrinsically quantum-mechanical phenomenon because it is not necessary to have a trap width that is the size of an atom - as might have been supposed - but it suffices merely to have a trap width such that the energy gap for motion in the transverse direction is large compared to the energy associated with the motion along the trap. Up to now the theoretical arguments have been based on variational - perturbative ideas or numerical investigations. In contrast, this paper gives a rigorous proof of the one-dimensional behavior as far as the ground state energy and particle density are concerned. There are four parameters involved: the particle number, N, transverse and longitudinal dimensions of the trap, r and L, and the scattering length a of the interaction potential. Our main result is that if r/L → 0 and N → ∞ the ground state energy and density can be obtained by minimizing a one-dimensional density functional involving the Lieb-Liniger energy density with coupling constant ∼ a/r 2. This density functional simplifies in various limiting cases and we identify five asymptotic parameter regions altogether. Three of these, corresponding to the weak coupling regime, can also be obtained as limits of a three-dimensional Gross-Pitaevskii theory. We also show that Bose-Einstein condensation in the ground state persists in a part of this regime. In the strong coupling regime the longitudinal motion of the particles is strongly correlated. The Gross-Pitaevskii description is not valid in this regime and new mathematical methods come into play.}, author = {Lieb, Élliott H and Robert Seiringer and Yngvason, Jakob}, journal = {Communications in Mathematical Physics}, number = {2}, pages = {347 -- 393}, publisher = {Springer}, title = {{One-dimensional behavior of dilute, trapped Bose gases}}, doi = {10.1007/s00220-003-0993-3}, volume = {244}, year = {2004}, } @article{2360, abstract = {An optical lattice model developed that is similar to the Bose-Hubbard model to describe the transition between Bose-Einstein condensation (BEC) and a Mott insulator state was analyzed. It was found that the system was a hard core lattice gas at half of the maximum density and the optical lattice was modeled by a periodic potential of strength λ. It was also observed that the interparticle interaction was essential for this transition that occurred even in the ground state. The results show that all the essential features could be proved rigorously such as the existence of BEC for small λ and its suppression for a large λ.}, author = {Aizenman, Michael and Lieb, Élliott H and Robert Seiringer and Solovej, Jan P and Yngvason, Jakob}, journal = {Physical Review A - Atomic, Molecular, and Optical Physics}, number = {2}, pages = {023612 -- 1--0236121--2}, publisher = {American Physical Society}, title = {{Bose-Einstein quantum phase transition in an optical lattice model}}, doi = {10.1103/PhysRevA.70.023612}, volume = {70}, year = {2004}, } @inbook{2417, author = {Lovász, László and Vesztergombi, Katalin and Uli Wagner and Welzl, Emo}, booktitle = {Towards a Theory of Geometric Graphs}, editor = {Pach, János}, pages = {139 -- 148}, publisher = {American Mathematical Society}, title = {{Convex quadrilaterals and k-sets }}, doi = {10.1090/conm/342}, volume = {342}, year = {2004}, } @article{2425, abstract = {A finite set N ⊂ Rd is a weak ε-net for an n-point set X ⊂ Rd (with respect to convex sets) if N intersects every convex set K with |K ∩ X| ≥ εn. We give an alternative, and arguably simpler, proof of the fact, first shown by Chazelle et al., that every point set X in Rd admits a weak ε-net of cardinality O(ε-dpolylog(1/ε)). Moreover, for a number of special point sets (e.g., for points on the moment curve), our method gives substantially better bounds. The construction yields an algorithm to construct such weak ε-nets in time O(n ln(1/ε)).}, author = {Matoušek, Jiří and Uli Wagner}, journal = {Discrete & Computational Geometry}, number = {2}, pages = {195 -- 206}, publisher = {Springer}, title = {{New constructions of weak ε-nets}}, doi = {10.1007/s00454-004-1116-4}, volume = {32}, year = {2004}, } @article{2426, abstract = {We introduce the adaptive neighborhood graph as a data structure for modeling a smooth manifold M embedded in some Euclidean space ℝ d. We assume that M is known to us only through a finite sample P ⊂ M, as is often the case in applications. The adaptive neighborhood graph is a geometric graph on P. Its complexity is at most min{2O(k)n, n2}, where n = P and k = dim M, as opposed to the n[d/2] complexity of the Delaunay triangulation, which is often used to model manifolds. We prove that we can correctly infer the connected components and the dimension of M from the adaptive neighborhood graph provided a certain standard sampling condition is fulfilled. The running time of the dimension detection algorithm is d20(k7 log k) for each connected component of M. If the dimension is considered constant, this is a constant-time operation, and the adaptive neighborhood graph is of linear size. Moreover, the exponential dependence of the constants is only on the intrinsic dimension k, not on the ambient dimension d. This is of particular interest if the co-dimension is high, i.e., if k is much smaller than d, as is the case in many applications. The adaptive neighborhood graph also allows us to approximate the geodesic distances between the points in P.}, author = {Giesen, Joachim and Uli Wagner}, journal = {Discrete & Computational Geometry}, number = {2}, pages = {245 -- 267}, publisher = {Springer}, title = {{Shape dimension and intrinsic metric from samples of manifolds}}, doi = {10.1007/s00454-004-1120-8}, volume = {32}, year = {2004}, } @misc{2461, author = {Sauer, Michael and Friml, Jirí}, booktitle = {Development}, number = {23}, pages = {5774 -- 5775}, publisher = {Company of Biologists}, title = {{The Matryoshka dolls of plant polarity}}, doi = {10.1242/dev.01463}, volume = {131}, year = {2004}, } @article{17717, abstract = {We demonstrate that constraints on cosmological parameters from the distribution of clusters as a function of redshift (dN/dz) are complementary to accurate angular diameter distance (D_A) measurements to clusters, and their combination significantly tightens constraints on the energy density content of the Universe. The number counts can be obtained from X-ray and/or SZ (Sunyaev-Zel'dovich effect) surveys, and the angular diameter distances can be determined from deep observations of the intra-cluster gas using their thermal bremsstrahlung X-ray emission and the SZ effect. We combine constraints from simulated cluster number counts expected from a 12 deg^2 SZ cluster survey and constraints from simulated angular diameter distance measurements based on the X-ray/SZ method assuming a statistical accuracy of 10% in the angular diameter distance determination of 100 clusters with redshifts less than 1.5. We find that Omega_m can be determined within about 25%, Omega_Lambda within 20%, and w within 16%. We show that combined dN/dz + D_A constraints can be used to constrain the different energy densities in the Universe even in the presence of a few percent redshift dependent systematic error in D_A. We also address the question of how best to select clusters of galaxies for accurate diameter distance determinations. We show that the joint dN/dz + D_A constraints on cosmological parameters for a fixed target accuracy in the energy density parameters are optimized by selecting clusters with redshift upper cut--offs in the range 0.5 < z < 1.}, author = {Molnar, Sandor M. and Haiman, Zoltán and Birkinshaw, Mark and Mushotzky, Richard F.}, issn = {0004-637X}, journal = {The Astrophysical Journal}, number = {1}, pages = {22--27}, publisher = {American Astronomical Society}, title = {{Constraints on the energy content of the universe from a combination of galaxy cluster observables}}, doi = {10.1086/380295}, volume = {601}, year = {2004}, }