@article{3721, abstract = {Recent advances in atomic force microscopy allowed globular and membrane proteins to be mechanically unfolded on a single-molecule level. Presented is an extension to the existing force spectroscopy experiments. While unfolding single bacteriorhodopsins from native purple membranes, small oscillation amplitudes (6–9nm) were supplied to the vertical displacement of the cantilever at a frequency of 3kHz. The phase and amplitude response of the cantilever-protein system was converted to reveal the elastic (conservative) and viscous (dissipative) contributions to the unfolding process. The elastic response (stiffness) of the extended parts of the protein were in the range of a few tens pN/nm and could be well described by the derivative of the wormlike chain model. Discrete events in the viscous response coincided with the unfolding of single secondary structure elements and were in the range of 1μNs/m. In addition, these force modulation spectroscopy experiments revealed novel mechanical unfolding intermediates of bacteriorhodopsin. We found that kinks result in a loss of unfolding cooperativity in transmembrane helices. Reconstructing force-distance spectra by the integration of amplitude-distance spectra verified their position, offering a novel approach to detect intermediates during the forced unfolding of single proteins.}, author = {Harald Janovjak and Mueller, Daniel J and Humphris, Andrew D}, journal = {Biophysical Journal}, number = {2}, pages = {1423 -- 1431}, publisher = {Biophysical Society}, title = {{Molecular force modulation spectroscopy revealing the dynamic response of single bacteriorhodopsins}}, doi = {10.1529/biophysj.104.052746}, volume = {88}, year = {2005}, } @article{3741, abstract = {In an age of increasingly large data sets, investigators in many different disciplines have turned to clustering as a tool for data analysis and exploration. Existing clustering methods, however, typically depend on several nontrivial assumptions about the structure of data. Here, we reformulate the clustering problem from an information theoretic perspective that avoids many of these assumptions. In particular, our formulation obviates the need for defining a cluster "prototype," does not require an a priori similarity metric, is invariant to changes in the representation of the data, and naturally captures nonlinear relations. We apply this approach to different domains and find that it consistently produces clusters that are more coherent than those extracted by existing algorithms. Finally, our approach provides a way of clustering based on collective notions of similarity rather than the traditional pairwise measures.}, author = {Slonim,N. and Atwal,G. and Gasper Tkacik and Bialek, William S}, journal = {PNAS}, number = {51}, pages = {18297 -- 18302}, publisher = {National Academy of Sciences}, title = {{Information-based clustering}}, doi = {10.1073/pnas.0507432102}, volume = {102}, year = {2005}, } @unpublished{3746, abstract = {We address the practical problems of estimating the information relations that characterize large networks. Building on methods developed for analysis of the neural code, we show that reliable estimates of mutual information can be obtained with manageable computational effort. The same methods allow estimation of higher order, multi-information terms. These ideas are illustrated by analyses of gene expression, financial markets, and consumer preferences. In each case, information theoretic measures correlate with independent, intuitive measures of the underlying structures in the system.}, author = {Slonim,Noam and Atwal,Gurinder S and Gasper Tkacik and Bialek, William S}, booktitle = {ArXiv}, pages = {1 -- 11}, publisher = {ArXiv}, title = {{Estimating mutual information and multi-information in large networks}}, year = {2005}, } @article{3753, abstract = {Characterizing the dynamics of specific RNA levels requires real-time RNA profiling in a single cell. We show that the combination of a synthetic modular genetic system with fluorescence correlation spectroscopy allows us to directly measure in real time the activity of any specific promoter in prokaryotes. Using a simple inducible gene expression system, we found that induced RNA levels within a single bacterium of Escherichia coli exhibited a pulsating profile in response to a steady input of inducer. The genetic deletion of an efflux pump system, a key determinant of antibiotic resistance, altered the pulsating transcriptional dynamics and caused overexpression of induced RNA. In contrast with population measurements, real-time RNA profiling permits identifying relationships between genotypes and transcriptional dynamics that are accessible only at the level of the single cell.}, author = {Le,Thuc T. and Harlepp, Sébastien and Calin Guet and Dittmar,Kimberly and Emonet,Thierry and Pan,Tao and Cluzel,Philippe}, journal = {PNAS}, number = {26}, pages = {9160 -- 9164}, publisher = {National Academy of Sciences}, title = {{Real-time RNA profiling within a single bacterium}}, doi = {10.1073/pnas.0503311102}, volume = {102}, year = {2005}, } @article{3763, abstract = {The generation of realistic motion satisfying user-defined requirements is one of the most important goals of computer animation. Our aim in this paper is the synthesis of realistic, controllable motion for lightweight natural objects in a gaseous medium. We formulate this problem as a large-scale spacetime optimization with user controls and fluid motion equations as constraints. We have devised novel and effective methods to make this large optimization tractable. Initial trajectories are generated with data-driven synthesis based on stylistic motion planning. Smoothed particle hydrodynamics (SPH) is used during optimization to produce fluid simulations at a reasonable computational cost, while interesting vortex-based fluid motion is generated by recording the presence of vortices in the initial trajectories and maintaining them through optimization. Object rotations are refined as a postprocess to enhance the visual quality of the results. We demonstrate our techniques on a number of animations involving single or multiple objects.}, author = {Shi, Lin and Yu, Yizhou and Wojtan, Christopher J and Chenney, Stephen}, journal = {The Visual Computer}, number = {7}, pages = {474 -- 487}, publisher = {Springer}, title = {{Controllable motion synthesis in a gaseous medium}}, doi = {10.1007/s00371-005-0296-0}, volume = {21}, year = {2005}, } @article{3808, abstract = {Action potentials in central neurons are initiated near the axon initial segment, propagate into the axon, and finally invade the presynaptic terminals, where they trigger transmitter release. Voltage-gated Na(+) channels are key determinants of excitability, but Na(+) channel density and properties in axons and presynaptic terminals of cortical neurons have not been examined yet. In hippocampal mossy fiber boutons, which emerge from parent axons en passant, Na(+) channels are very abundant, with an estimated number of approximately 2000 channels per bouton. Presynaptic Na(+) channels show faster inactivation kinetics than somatic channels, suggesting differences between subcellular compartments of the same cell. Computational analysis of action potential propagation in axon-multibouton structures reveals that Na(+) channels in boutons preferentially amplify the presynaptic action potential and enhance Ca(2+) inflow, whereas Na(+) channels in axons control the reliability and speed of propagation. Thus, presynaptic and axonal Na(+) channels contribute differentially to mossy fiber synaptic transmission.}, author = {Engel, Dominique and Peter Jonas}, journal = {Neuron}, number = {3}, pages = {405 -- 17}, publisher = {Elsevier}, title = {{Presynaptic action potential amplification by voltage-gated Na+ channels in hippocampal mossy fiber boutons}}, doi = {10.1016/j.neuron.2004.12.048 }, volume = {45}, year = {2005}, } @misc{3812, abstract = {Hippocampal GABAergic interneurons show diverse molecular and morphological properties. The functional significance of this diversity for information processing is poorly understood. Here we show that cholecystokinin (CCK)-expressing interneurons in rat dentate gyrus release GABA in a highly asynchronous manner, in contrast to parvalbumin (PV) interneurons. With a gamma-frequency burst of ten action potentials, the ratio of asynchronous to synchronous release is 3:1 in CCK interneurons but is 1:5 in parvalbumin interneurons. N-type channels trigger synchronous and asynchronous release in CCK interneuron synapses, whereas P/Q-type Ca(2+) channels mediate release at PV interneuron synapses. Effects of Ca(2+) chelators suggest that both a long-lasting presynaptic Ca(2+) transient and a large distance between Ca(2+) source and sensor of exocytosis contribute to the higher ratio of asynchronous to synchronous release in CCK interneuron synapses. Asynchronous release occurs at physiological temperature and with behaviorally relevant stimulation patterns, thus generating long-lasting inhibition in the brain.}, author = {Hefft, Stefan and Peter Jonas}, booktitle = {Nature Neuroscience}, number = {10}, pages = {1319 -- 28}, publisher = {Nature Publishing Group}, title = {{Asynchronous GABA release generates long-lasting inhibition at a hippocampal interneuron-principal neuron synapse (Review)}}, doi = {10.1038/nn1542}, volume = {8}, year = {2005}, } @inproceedings{3892, abstract = {In 2-player non-zero-sum games, Nash equilibria capture the options for rational behavior if each player attempts to maximize her payoff. In contrast to classical game theory, we consider lexicographic objectives: first, each player tries to maximize her own payoff, and then, the player tries to minimize the opponent's payoff. Such objectives arise naturally in the verification of systems with multiple components. There, instead of proving that each component satisfies its specification no matter how the other components behave, it often suffices to prove that each component satisfies its specification provided that the other components satisfy their specifications. We say that a Nash equilibrium is secure if it is an equilibrium with respect to the lexicographic objectives of both players. We prove that in graph games with Borel winning conditions, which include the games that arise in verification, there may be several Nash equilibria, but there is always a unique maximal payoff profile of a secure equilibrium. We show how this equilibrium can be computed in the case of omega-regular winning conditions, and we characterize the memory requirements of strategies that achieve the equilibrium.}, author = {Krishnendu Chatterjee and Thomas Henzinger and Jurdziński, Marcin}, pages = {141 -- 161}, publisher = {Springer}, title = {{Games with secure equilibria}}, doi = {10.1007/11561163_7}, volume = {3657}, year = {2005}, } @inproceedings{3893, abstract = {We study infinite stochastic games played by two-players on a finite graph with goals specified by sets of infinite traces. The games are concurrent (each player simultaneously and independently chooses an action at each round), stochastic (the next state is determined by a probability distribution depending on the current state and the chosen actions), infinite (the game continues for an infinite number of rounds), nonzero-sum (the players' goals are not necessarily conflicting), and undiscounted. We show that if each player has an W-regular objective expressed as a paxity objective, then there exists an epsilon-Nash equilibrium, for every epsilon > 0. However, exact Nash equilibria need not exist. We study the complexity of finding values (payoff profile) of an epsilon-Nash equilibrium. We show that the values of an epsilon-Nash equilibrium in nonzero-sum concurrent parity games can be computed by solving the following two simpler problems: computing the values of zero-sum (the goals of the players axe strictly conflicting) concurrent parity games and computing epsilon-Nash equilibrium values of nonzero-sum concurrent games with reachability objectives. As a consequence we establish that values of an epsilon-Nash equilibrium can be computed in TFNP (total functional NP), and hence in EXPTIME.}, author = {Krishnendu Chatterjee}, pages = {413 -- 427}, publisher = {Schloss Dagstuhl - Leibniz-Zentrum für Informatik}, title = {{Two-player nonzero-sum ω-regular games}}, doi = {10.1007/11539452_32}, volume = {3653}, year = {2005}, } @inproceedings{3896, abstract = {Temporal Logic Model Checking is one of the most potent tools for the verification of finite state systems. Computation Tree Logic (CTL) has gained popularity because unlike most other logics, CTL model checking of a single transition system can be achieved in polynomial time. However, in most real-life problems, specially in distributed and parallel systems, the system consist of a set of concurrent processes and the verification problem translates to model check the composition of the component processes. Since explicit composition leads to state explosion, verifying the system without actually composing the components is attractive, even for possibly restrictive class of systems. We show that the problem of compositional CTL model checking is PSPACE complete for the class of systems composed of components that are tree-like transition structure and do not interact among themselves. For the simplest forms of existential and universal CTL formulas model checking turns out to be NP complete and coNP complete, respectively. The results hold for both synchronous and asynchronous composition.}, author = {Krishnendu Chatterjee and Dasgupta, Pallab and Chakrabarti, Partha P}, pages = {89 -- 102}, publisher = {Springer}, title = {{Complexity of compositional model checking of computation tree logic on simple structures}}, doi = {10.1007/978-3-540-30536-1_13}, volume = {3326}, year = {2005}, } @inproceedings{3902, author = {Cremer, Sylvia and Boomsma, Jacobus}, publisher = {Elsevier}, title = {{The drawback of mobility: invasive species in a globalised world}}, year = {2005}, } @article{3915, abstract = {In the ant Cardiocondyla obscurior, wingless males compete with nestmate males for access to female mating partners, leading to local mate competition (LMC). Queen number varies between colonies, resulting in variation in the strength of LMC. Cremer & Heinze (2002, Proceedings of the Royal Society of London, Series B, 269, 417–422) showed that colonies responded to increasing queen number by producing a less femalebiased sex ratio, as predicted by LMC theory. However, the proximate mechanisms responsible for this variation in the sex ratio could not be determined because the study was restricted to adult sex ratios.With LMC, the primary sex ratio (proportion of haploid eggs laid by the queen) is expected to be female biased, which lowers the conflict between queens and workers over sex allocation. We compared the primary sex ratios laid by queens in monogynous and in polygynous experimental colonies of C. obscurior. The proportion of haploid eggs laid by queens was significantly lower in single-queen than in multiple-queen colonies. Furthermore, queens rapidly adjusted their primary sex ratios to changes in colony queen number. This is the first report of an adaptive adjustment of the primary sex ratio in response to LMC by ant queens.}, author = {De Menten, Ludivine and Cremer, Sylvia and Heinze, Jürgen and Aron, Serge}, journal = {Animal Behaviour}, number = {5}, pages = {1031 -- 1035}, publisher = {Elsevier}, title = {{Primary sex ratio adjustment by ant queens in response to local mate competition}}, doi = {10.1016/j.anbehav.2004.09.005}, volume = {69}, year = {2005}, } @article{3916, abstract = {Divergent reproductive interests of males and females often cause sexual conflict [1] and [2]. Males of many species manipulate females by transferring seminal fluids that boost female short-term fecundity while decreasing their life expectancy and future reproductivity [3] and [4]. The life history of ants, however, is expected to reduce sexual conflict; whereas most insect females show repeated phases of mating and reproduction, antqueens mate only during a short period early in life and undergo a lifelong commitment to their mates by storing sperm [5]. Furthermore, sexual offspring can only be reared after a sterile worker force has been built up [5]. Therefore, the males should also profit from a long female lifespan. In the antCardiocondyla obscurior, mating indeed has a positive effect on the lifetime reproductive success of queens. Queens that mated to either one fertile or one sterilized male lived considerably longer and started laying eggs earlier than virgin queens. Only queens that received viable sperm from fertile males showed increased fecundity. The lack of a trade-off between fecundity and longevity is unexpected, given evolutionary theories of aging [6]. Our data instead reveal the existence of sexual cooperation in ants.}, author = {Schrempf, Alexandra and Heinze, Jürgen and Cremer, Sylvia}, journal = {Current Biology}, number = {3}, pages = {267 -- 270}, publisher = {Cell Press}, title = {{Sexual cooperation: mating increases longevity in ant queens}}, doi = {10.1016/j.cub.2005.01.036}, volume = {15}, year = {2005}, } @article{3933, abstract = {Resident dendritic cells (DC) within the T cell area of the lymph node take up soluble antigens that enter via the afferent lymphatics before antigen carrying DC arrive from the periphery. The reticular network within the lymph node is a conduit system forming the infrastructure for the fast delivery of soluble substances from the afferent lymph to the lumen of high endothelial venules (HEVs). Using high-resolution light microscopy and 3D reconstruction, we show here that these conduits are unique basement membrane-like structures ensheathed by fibroblastic reticular cells with occasional resident DC embedded within this cell layer. Conduit-associated DC are capable of taking up and processing soluble antigens transported within the conduits, whereas immigrated mature DC occur remote from the reticular fibers. The conduit system is, therefore, not a closed compartment that shuttles substances through the lymph node but represents the morphological equivalent to the filtering function of the lymph node.}, author = {Sixt, Michael K and Kanazawa, Nobuo and Selg, Manuel and Samson, Thomas and Roos, Gunnel and Reinhardt, Dieter and Pabst, Reinhard and Lutz, Manfred and Sorokin, Lydia}, journal = {Immunity}, number = {1}, pages = {19 -- 29}, publisher = {Cell Press}, title = {{The conduit system transports soluble antigens from the afferent lymph to resident dendritic cells in the T cell area of the lymph node}}, doi = {10.1016/j.immuni.2004.11.013}, volume = {22}, year = {2005}, } @inproceedings{3989, abstract = {We introduce local and global comparison measures for a collection of k less than or equal to d real-valued smooth functions on a common d-dimensional Riemannian manifold. For k = d = 2 we relate the measures to the set of critical points of one function restricted to the level sets of the other. The definition of the measures extends to piecewise linear functions for which they ace easy to compute. The computation of the measures forms the centerpiece of a software tool which we use to study scientific datasets.}, author = {Edelsbrunner, Herbert and Harer, John and Natarajan, Vijay and Pascucci, Valerio}, isbn = {0780387880}, location = {Austin, TX, United States}, pages = {275 -- 280}, publisher = {IEEE}, title = {{Local and global comparison of continuous functions}}, doi = {10.1109/VISUAL.2004.68}, year = {2005}, } @article{17715, abstract = {At redshifts beyond z>6, as the mean fraction of neutral hydrogen x_HI in the intergalactic medium (IGM) increases, the line flux of Lyman alpha (Lya) emitters can be significantly suppressed, which can result in a decrease in the observed number of emitters at a given Lya flux. However, cosmological HII regions surrounding the Lya emitting galaxies alleviate these effects. We use simple models of the Lya line suppression that incorporate the presence of HII regions to predict the overall effect of the Lya absorption on the Lya luminosity function. We find, in agreement with other recent studies, that unless ionizing sources are unusually strongly clustered, a fully neutral IGM may be inconsistent with the large abundance of confirmed z=6.5 Lya emitters. However, the presence of local HII regions prohibits placing a tight constraint on the mean neutral fraction. We find x_HI < 0.25; the presence of strong winds and/or the clustering of ionizing sources would further weaken this constraint. We conclude that the evolution of the Lya LF is consistent with reionization occurring near this redshift. Finally, we suggest that a measurement of observed Lya line width as a function of the Lya luminosity, in a future, larger sample of Lya emitters, may serve as a robust diagnostic of the neutral fraction in the IGM.}, author = {Haiman, Zoltán and Cen, Renyue}, issn = {0004-637X}, journal = {The Astrophysical Journal}, number = {2}, pages = {627--631}, publisher = {American Astronomical Society}, title = {{Constraining reionization with the evolution of the luminosity function of Lyα emitting galaxies}}, doi = {10.1086/428645}, volume = {623}, year = {2005}, } @article{17720, abstract = {We revisit the possibility of detecting an extrasolar planet around a background star as it crosses the fold caustic of a foreground binary lens. During such an event, the planet's flux can be magnified by a factor of ~100 or more. The detectability of the planet depends strongly on the orientation of its orbit relative to the caustic. If the source star is inside the intercaustic region, detecting the caustic-crossing planet is difficult against the magnified flux of its parent star. In the more favorable configuration, when the star is outside the intercaustic region when the planet crosses the caustic, a close-in Jupiter-like planet around a Sun-like star at a distance of 8 kpc is detectable in 8 minute integrations with a 10 m telescope at maximal signal-to-noise ratio (S/N) ~15 for phase angle ϕ ~ 10°. In this example, we find further that the presence of methane, at its measured abundance in Jupiter, and/or water, sodium, and potassium, at the abundances expected in theoretical atmosphere models of close-in Jupiters, could be inferred from a nondetection of the planet in strong broad absorption bands at 0.6-1.4 μm caused by these compounds, accompanied by a S/N ~ 10 detection in adjacent bands. We conclude that future generations of large telescopes might be able to probe the composition of the atmospheres of distant extrasolar planets.}, author = {Spiegel, David S. and Zamojski, Michel and Gersch, Alan and Donovan, Jennifer and Haiman, Zoltán}, issn = {0004-637X}, journal = {The Astrophysical Journal}, number = {1}, pages = {478--486}, publisher = {American Astronomical Society}, title = {{Can we probe the atmospheric composition of an extrasolar planet from its reflection spectrum in a high‐magnification microlensing event?}}, doi = {10.1086/430696}, volume = {628}, year = {2005}, } @article{17731, abstract = {In cosmological structure formation models, massive non-linear objects in the process of formation, such as galaxy clusters, are surrounded by large-scale shocks at or around the expected virial radius. Direct observational evidence for such virial shocks is currently lacking, but we show here that their presence can be inferred from future, high resolution, high-sensitivity observations of the Sunyaev-Zel'dovich (SZ) effect in galaxy clusters. We study the detectability of virial shocks in mock SZ maps, using simple models of cluster structure (gas density and temperature distributions) and noise (background and foreground galaxy clusters projected along the line of sight, as well as the cosmic microwave background anisotropies). We find that at an angular resolution of 2'' and sensitivity of 10 micro K, expected to be reached at ~ 100 GHz frequencies in a ~ 20 hr integration with the forthcoming ALMA instrument, virial shocks associated with massive M ~ 10^15 M_Sun clusters will stand out from the noise, and can be detected at high significance. More generally, our results imply that the projected SZ surface brightness profile in future, high-resolution experiments will provide sensitive constraints on the density profile of cluster gas.}, author = {Kocsis, Bence and Haiman, Zoltán and Frei, Zsolt}, issn = {0004-637X}, journal = {The Astrophysical Journal}, number = {2}, pages = {632--649}, publisher = {American Astronomical Society}, title = {{Can virialization shocks be detected around galaxy clusters through the Sunyaev‐Zel’dovich effect?}}, doi = {10.1086/427975}, volume = {623}, year = {2005}, } @article{17737, abstract = {Cosmological models that include suppression of the power spectrum of density fluctuations on small scales exhibit an exponential reduction of high-redshift, non-linear structures, including a reduction in the rate of gamma ray bursts (GRBs). Here we quantify the constraints that the detection of distant GRBs would place on structure formation models with reduced small-scale power. We compute the number of GRBs that could be detectable by the Swift satellite at high redshifts (z > 6), assuming that the GRBs trace the cosmic star formation history, which itself traces the formation of non-linear structures. We calibrate simple models of the intrinsic luminosity function of the bursts to the number and flux distribution of GRBs observed by the Burst And Transient Source Experiment (BATSE). We find that a discovery of high-z GRBs would imply strong constraints on models with reduced small-scale power. For example, a single GRB at z > 10, or 10 GRBs at z > 5, discovered by Swift during its scheduled two-year mission, would rule out an exponential suppression of the power spectrum on scales below R_c=0.09 Mpc (exemplified by warm dark matter models with a particle mass of m_x=2 keV). Models with a less sharp suppression of small-scale power, such as those with a red tilt or a running scalar index, n_s, are more difficult to constrain, because they are more degenerate with an increase in the power spectrum normalization, sigma_8, and with models in which star-formation is allowed in low-mass minihalos. We find that a tilt of \delta n_s ~ 0.1 is difficult to detect; however, an observed rate of 1 GRB/yr at z > 12 would yield an upper limit on the running of the spectral index, alpha = d(n_s)/d(ln k) > -0.05.}, author = {Mesinger, Andrei and Perna, Rosalba and Haiman, Zoltán}, issn = {0004-637X}, journal = {The Astrophysical Journal}, number = {1}, pages = {1--10}, publisher = {American Astronomical Society}, title = {{Constraints on the small‐scale power spectrum of density fluctuations from high‐redshift gamma‐ray bursts}}, doi = {10.1086/428770}, volume = {623}, year = {2005}, } @article{17761, abstract = {We explore the possibility of resolving an image of a damped Lyα (DLA) system in absorption against an extended, diffuse, background X-ray source. Typical columns of neutral hydrogen in DLA systems are high enough to block out up to ~30% of the soft X-ray flux at an observed photon energy of 0.5 keV, and we find that ~1% of the area of extended X-ray sources at z ≳ 1 have their 0.5 keV flux reduced by at least 20% because of intervening DLA systems. We discuss the observability of such absorption and find that ≳300 photons per angular resolution element are required in the 0.3-8 keV band for its detection and in order to distinguish it from intrinsic surface brightness fluctuations. For the surface brightness of the currently known high-redshift extended X-ray sources, this requires an integration time of a few megaseconds on Chandra, if the maps are smoothed spatially to ≈2'' resolution. The exact required integration time depends on the DLA system's column density, metallicity, and, most strongly, its redshift. Current X-ray telescopes are likely to detect DLA systems with N < 10^22 cm^-2 only out to z ≈ 2.3. The availability of DLA systems with a suitably high column density for a silhouette detection is currently poorly known. We suggest that at low redshifts archival data of bright X-ray point sources may be useful in constraining the high-N end of the column density distribution. We briefly discuss an alternative strategy of searching for extended X-ray sources behind known DLA systems. Although with current X-ray telescopes the detections are challenging, they will be within the reach of a routine observation with a next generation X-ray telescope, such as the X-Ray Evolving Universe Spectrometer (XEUS) or Generation-X, and will deliver novel constraints on the nature of protogalaxies.}, author = {Dijkstra, Mark and Haiman, Zoltán and Scharf, Caleb}, issn = {0004-637X}, journal = {The Astrophysical Journal}, number = {1}, pages = {85--93}, publisher = {American Astronomical Society}, title = {{On detecting the X‐ray silhouette of a damped Lyα system}}, doi = {10.1086/428766}, volume = {624}, year = {2005}, }