@article{7781, abstract = {Males are predicted to compete for reproductive opportunities, with sexual selection driving the evolution of large body size and weaponry through the advantage they confer for access to females. Few studies have explored potential trade‐offs of investment in secondary sexual traits between different components of fitness or tested for sexually antagonistic selection pressures. These factors may provide explanations for observed polymorphisms in both form and quality of secondary sexual traits. We report here an analysis of selection on horn phenotype in a feral population of Soay sheep (Ovis aries) on the island of Hirta, St. Kilda, Scotland. Soay sheep display a phenotypic polymorphism for horn type with males growing either normal or reduced (scurred) horns, and females growing either normal, scurred, or no (polled) horns; further variation in size exists within horn morphs. We show that horn phenotype and the size of the trait displayed is subject to different selection pressures in males and females, generating sexually antagonistic selection. Furthermore, there was evidence of a trade‐off between breeding success and longevity in normal‐horned males, with both the normal horn type and larger horn size being associated with greater annual breeding success but reduced longevity. Therefore, selection through lifetime breeding success was not found to act upon horn phenotype in males. In females, a negative association of annual breeding success within the normal‐horned phenotype did not result in a significant difference in lifetime fitness when compared to scurred individuals, as no significant difference in longevity was found. However, increased horn size within this group was negatively associated with breeding success and longevity. Females without horns (polled) suffered reduced longevity and thus reduced lifetime breeding success relative the other horn morphs. Our results therefore suggest that trade‐offs between different components of fitness and antagonistic selection between the sexes may maintain genetic variation for secondary sexual traits within a population.}, author = {Robinson, Matthew Richard and Pilkington, Jill G. and Clutton-Brock, Tim H. and Pemberton, Josephine M. and Kruuk, Loeske E.B.}, issn = {0014-3820}, journal = {Evolution}, number = {10}, pages = {2168--2181}, publisher = {Wiley}, title = {{Live fast, die young: Trade-offs between fitness components and sexually antagonistic selection on weaponry in soay sheep}}, doi = {10.1111/j.0014-3820.2006.tb01854.x}, volume = {60}, year = {2007}, } @article{8027, abstract = {Gating deficits and hallucinatory sensations are prominent symptoms of schizophrenia. Comparing these abnormalities with the failure modes of network models is an interesting way to explore how they arise. We present a network model that can both propagate and gate signals. The model exhibits effects reminiscent of clinically observed pathologies when the balance between excitation and inhibition that it requires is not properly maintained.}, author = {Vogels, Tim P and Abbott, L.}, issn = {0176-3679}, journal = {Pharmacopsychiatry}, number = {S 1}, pages = {S73--S77}, publisher = {Thieme}, title = {{Gating deficits in model networks: A path to schizophrenia?}}, doi = {10.1055/s-2007-992130}, volume = {40}, year = {2007}, } @inbook{167, abstract = {This book contains research articles on Diophantine Geometry, written by participants of a research program held at the Ennio De Giorgi Mathematical Research Center in Pisa, Italy, during the period April – July 2005. The authors are eminent experts in the field. Several subfields of the main topic are presented; the volume thus is particularly useful to get a broad overview of recent research developments.}, author = {Browning, Timothy D and Heath Brown, Roger}, booktitle = {Diophantine Geometry}, editor = {Zannier, Umberto}, pages = {93 -- 100}, publisher = {Edizioni della Normale}, title = {{Simultaneous equal sums of three powers}}, volume = {4}, year = {2007}, } @article{1750, abstract = {The authors investigate the composition profile of SiGe islands after capping with Si to form quantum dots, using a two step etching procedure and atomic force microscopy. Initially, the Si capping layers are removed by etching selectively Si over Ge and then the composition of the disclosed islands is addressed by selectively etching Ge over Si. For samples grown at 580 °C the authors show that even when overgrowth leads to a flat Si surface and the islands undergo strong morphological changes, a Ge-rich core region is still preserved in the dot. At high growth and overgrowth temperatures (740 °C), the experiments show that the newly formed base of the buried islands is more Si rich than their top. Furthermore, the authors find that for the growth conditions used, no lateral motion takes place during capping.}, author = {Georgios Katsaros and Stoffel, Mathieu and Rastelli, Armando and Schmidt, Oliver G and Kern, Klaus and Tersoff, Jerry}, journal = {Applied Physics Letters}, number = {1}, publisher = {American Institute of Physics}, title = {{Three-dimensional isocompositional profiles of buried SiGeSi (001) islands}}, doi = {10.1063/1.2752730}, volume = {91}, year = {2007}, } @article{1762, abstract = {In quantum information science, the phase of a wave function plays an important role in encoding information. Although most experiments in this field rely on dynamic effects to manipulate this information, an alternative approach is to use geometric phase, which has been argued to have potential fault tolerance. We demonstrated the controlled accumulation of a geometric phase, Berry's phase, in a superconducting qubit; we manipulated the qubit geometrically by means of microwave radiation and observed the accumulated phase in an interference experiment. We found excellent agreement with Berry's predictions and also observed a geometry-dependent contribution to dephasing.}, author = {Leek, Peter J and Johannes Fink and Blais, Alexandre and Bianchetti, R and Göppl, M and Gambetta, Jay M and Schuster, David I and Frunzio, Luigi and Schoelkopf, Robert J and Wallraff, Andreas}, journal = {Science}, number = {5858}, pages = {1889 -- 1892}, publisher = {American Association for the Advancement of Science}, title = {{Observation of Berry's phase in a solid-state qubit}}, doi = {10.1126/science.1149858}, volume = {318}, year = {2007}, } @article{1797, abstract = {Intrinsically photosensitive melanopsin-containing retinal ganglion cells (ipRGCs) control important physiological processes, including the circadian rhythm, the pupillary reflex, and the suppression of locomotor behavior (reviewed in [1]). ipRGCs are also activated by classical photoreceptors, the rods and cones, through local retinal circuits [2, 3]. ipRGCs can be transsynaptically labeled through the pupillary-reflex circuit with the derivatives of the Bartha strain of the alphaherpesvirus pseudorabies virus(PRV) [4, 5] that express GFP [6-12]. Bartha-strain derivatives spread only in the retrograde direction [13]. There is evidence that infected cells function normally for a while during GFP expression [7]. Here we combine transsynaptic PRV labeling, two-photon laser microscopy, and electrophysiological techniques to trace the local circuit of different ipRGC subtypes in the mouse retina and record light-evoked activity from the transsynaptically labeled ganglion cells. First, we show that ipRGCs are connected by monostratified amacrine cells that provide strong inhibition from classical-photoreceptor-driven circuits. Second, we show evidence that dopaminergic interplexiform cells are synaptically connected to ipRGCs. The latter finding provides a circuitry link between light-dark adaptation and ipRGC function.}, author = {Viney, Tim J and Bálint, Kamill and Hillier, Dániel and Sandra Siegert and Boldogköi, Zsolt S and Enquist, Lynn W and Meister, Markus and Cepko, Constance L and Roska, Botond M}, journal = {Current Biology}, number = {11}, pages = {981 -- 988}, publisher = {Cell Press}, title = {{Local retinal circuits of melanopsin-containing ganglion cells identified by transsynaptic viral tracing}}, doi = {10.1016/j.cub.2007.04.058}, volume = {17}, year = {2007}, } @article{1964, abstract = {Complex I of respiratory chains plays a central role in cellular energy production. Mutations in its subunits lead to many human neurodegenerative diseases. Recently, a first atomic structure of the hydrophilic domain of complex I from Thermus thermophilus was determined. This domain represents a catalytic core of the enzyme. It consists of eight different subunits, contains all the redox centers, and comprises more than half of the entire complex. In this review, novel mechanistic implications of the structure are discussed, and the effects of many known mutations of complex I subunits are interpreted in a structural context.}, author = {Leonid Sazanov}, journal = {Biochemistry}, number = {9}, pages = {2275 -- 2288}, publisher = {ACS}, title = {{Respiratory complex I: Mechanistic and structural insights provided by the crystal structure of the hydrophilic domain}}, doi = {10.1021/bi602508x}, volume = {46}, year = {2007}, } @article{1965, abstract = {Respiratory complex I (NADH:ubiquinone oxidoreductase) is an L-shaped multisubunit protein assembly consisting of a hydrophobic membrane arm and a hydrophilic peripheral arm. It catalyses the transfer of two electrons from NADH to quinone coupled to the translocation of four protons across the membrane. Although we have solved recently the crystal structure of the peripheral arm, the structure of the complete enzyme and the coupling mechanism are not yet known. The membrane domain of Escherichia coli complex I consists of seven different subunits with total molecular mass of 258 kDa. It is significantly more stable than the whole enzyme, which allowed us to obtain well-ordered two-dimensional crystals of the domain, belonging to the space group p22121. Comparison of the projection map of negatively stained crystals with previously published low-resolution structures indicated that the characteristic curved shape of the membrane domain is remarkably well conserved between bacterial and mitochondrial enzymes, helping us to interpret projection maps in the context of the intact complex. Two pronounced stain-excluding densities at the distal end of the membrane domain are likely to represent the two large antiporter-like subunits NuoL and NuoM. Cryo-electron microscopy on frozen-hydrated crystals allowed us to calculate a projection map at 8 Å resolution. About 60 transmembrane α-helices, both perpendicular to the membrane plane and tilted, are present within one membrane domain, which is consistent with secondary structure predictions. A possible binding site and access channel for quinone are found at the interface with the peripheral arm. Tentative assignment of individual subunits to the features of the map has been made. The location of subunits NuoL and NuoM at substantial distance from the peripheral arm, which contains all the redox centres of the complex, indicates that conformational changes are likely to play a role in the mechanism of coupling between electron transfer and proton pumping.}, author = {Baranova, Ekaterina A and Holt, Peter J and Leonid Sazanov}, journal = {Journal of Molecular Biology}, number = {1}, pages = {140 -- 154}, publisher = {Elsevier}, title = {{Projection structure of the membrane domain of Escherichia coli respiratory Complex I at 8 Å resolution}}, doi = {10.1016/j.jmb.2006.11.026}, volume = {366}, year = {2007}, } @article{1969, abstract = {Respiratory complex I catalyses the transfer of electrons from NADH to quinone coupled to the translocation of protons across the membrane. The mechanism of coupling and the structure of the complete enzyme are not known. The membrane domain of the complex contains three similar antiporter-like subunits NuoL/M/N, probably involved in proton pumping. We have previously shown that subunits NuoL/M can be removed from the rest of the complex, suggesting their location at the distal end of the membrane domain. Here, using electron microscopy and single particle analysis, we show that subunits NuoL and M jointly occupy a distal half of the membrane domain, separated by about 10 nm from the interface with the peripheral arm. This indicates that coupling mechanism of complex I is likely to involve long range conformational changes.}, author = {Baranova, Ekaterina A and Morgan, David J and Leonid Sazanov}, journal = {Journal of Structural Biology}, number = {2 SPEC. ISS.}, pages = {238 -- 242}, publisher = {Academic Press}, title = {{Single particle analysis confirms distal location of subunits NuoL and NuoM in Escherichia coli complex I}}, doi = {10.1016/j.jsb.2007.01.009}, volume = {159}, year = {2007}, } @article{13424, abstract = {Changing shapes: Metastable spherical aggregates of gold nanoparticles undergo a one-to-one, thermally induced transformation into heterodimers comprising connected plate and spherical domains. By controlling the reaction time, it is possible to isolate a variety of structures differing in the relative sizes of the domains and in the overall optical properties (see picture).}, author = {Klajn, Rafal and Pinchuk, Anatoliy O. and Schatz, George C. and Grzybowski, Bartosz A.}, issn = {1521-3773}, journal = {Angewandte Chemie International Edition}, keywords = {General Chemistry, Catalysis}, number = {44}, pages = {8363--8367}, publisher = {Wiley}, title = {{Synthesis of heterodimeric sphere–prism nanostructures via metastable gold supraspheres}}, doi = {10.1002/anie.200702570}, volume = {46}, year = {2007}, } @article{13425, abstract = {Nanoparticles (NPs) decorated with ligands combining photoswitchable dipoles and covalent cross-linkers can be assembled by light into organized, three-dimensional suprastructures of various types and sizes. NPs covered with only few photoactive ligands form metastable crystals that can be assembled and disassembled “on demand” by using light of different wavelengths. For higher surface concentrations, self-assembly is irreversible, and the NPs organize into permanently cross-linked structures including robust supracrystals and plastic spherical aggregates.}, author = {Klajn, Rafal and Bishop, Kyle J. M. and Grzybowski, Bartosz A.}, issn = {1091-6490}, journal = {Proceedings of the National Academy of Sciences}, keywords = {Multidisciplinary}, number = {25}, pages = {10305--10309}, publisher = {Proceedings of the National Academy of Sciences}, title = {{Light-controlled self-assembly of reversible and irreversible nanoparticle suprastructures}}, doi = {10.1073/pnas.0611371104}, volume = {104}, year = {2007}, } @article{13426, abstract = {Photoswelling of thin films of dichromated gelatin provides a basis for fabrication of multilevel surface reliefs via sequential UV illumination through different photomasks. The remarkable feature of this simple, benchtop technique is that by adjusting irradiation times, film thickness, or its hydration state the heights of the developed features can be varied from few nanometers to tens of microns. After UV exposure, the surface structures can be replicated faithfully into either soft or hard PDMS stamps.}, author = {Paszewski, Maciej and Smoukov, Stoyan K. and Klajn, Rafal and Grzybowski, Bartosz A.}, issn = {1520-5827}, journal = {Langmuir}, keywords = {Electrochemistry, Spectroscopy, Surfaces and Interfaces, Condensed Matter Physics, General Materials Science}, number = {10}, pages = {5419--5422}, publisher = {American Chemical Society}, title = {{Multilevel surface nano- and microstructuring via sequential photoswelling of dichromated gelatin}}, doi = {10.1021/la062982c}, volume = {23}, year = {2007}, } @article{13427, abstract = {Deformable, spherical aggregates of metal nanoparticles connected by long-chain dithiol ligands self-assemble into nanostructured materials of macroscopic dimensions. These materials are plastic and moldable against arbitrarily shaped masters and can be thermally hardened into polycrystalline metal structures of controllable porosity. In addition, in both plastic and hardened states, the assemblies are electrically conductive and exhibit Ohmic characteristics down to ∼20 volts per meter. The self-assembly method leading to such materials is applicable both to pure metals and to bimetallic structures of various elemental compositions.}, author = {Klajn, Rafal and Bishop, Kyle J. M. and Fialkowski, Marcin and Paszewski, Maciej and Campbell, Christopher J. and Gray, Timothy P. and Grzybowski, Bartosz A.}, issn = {1095-9203}, journal = {Science}, keywords = {Multidisciplinary}, number = {5822}, pages = {261--264}, publisher = {American Association for the Advancement of Science}, title = {{Plastic and moldable metals by self-assembly of sticky nanoparticle aggregates}}, doi = {10.1126/science.1139131}, volume = {316}, year = {2007}, } @inproceedings{582, abstract = {Using the techniques of "quantum weak-measurements" as a coherent amplification mechanism for small signals, for the first time we have measured the recently proposed "spin Hall effect" of light.}, author = {Onur Hosten and Kwiat, Paul G}, publisher = {OSA}, title = {{Observing the spin hall effect of light via quantum weak measurements}}, doi = {10.1364/FIO.2007.JTuA4}, year = {2007}, } @article{6150, author = {Gumienny, Tina L. and MacNeil, Lesley T. and Wang, Huang and de Bono, Mario and Wrana, Jeffrey L. and Padgett, Richard W.}, issn = {0960-9822}, journal = {Current Biology}, number = {2}, pages = {159--164}, publisher = {Elsevier}, title = {{Glypican LON-2 is a conserved negative regulator of BMP-like signaling in Caenorhabditis elegans}}, doi = {10.1016/j.cub.2006.11.065}, volume = {17}, year = {2007}, } @unpublished{6321, abstract = {These lecture notes describe the current state of affairs for Manin's conjecture in the context of del Pezzo surfaces.}, author = {Browning, Timothy D}, booktitle = {arXiv}, title = {{The Manin conjecture in dimension 2}}, year = {2007}, } @inbook{6323, abstract = {This paper surveys recent progress towards the Manin conjecture for (singular and non-singular) del Pezzo surfaces. To illustrate some of the techniques available, an upper bound of the expected order of magnitude is established for a singular del Pezzo surface of degree four.}, author = {Browning, Timothy D}, booktitle = {A Tribute to Gauss and Dirichlet}, pages = {39--56}, publisher = {American Mathematical Society}, title = {{An overview of Manin's conjecture for del Pezzo surfaces}}, volume = {7}, year = {2007}, } @article{1035, abstract = {We explore the rich internal structure of Cs2 Feshbach molecules. Pure ultracold molecular samples are prepared in a CO2 -laser trap, and a multitude of weakly bound states is populated by elaborate magnetic-field ramping techniques. Our methods use different Feshbach resonances as input ports and various internal level crossings for controlled state transfer. We populate higher partial-wave states of up to eight units of rotational angular momentum (l -wave states). We investigate the molecular structure by measurements of the magnetic moments for various states. Avoided level crossings between different molecular states are characterized through the changes in magnetic moment and by a Landau-Zener tunneling method. Based on microwave spectroscopy, we present a precise measurement of the magnetic-field-dependent binding energy of the weakly bound s -wave state that is responsible for the large background scattering length of Cs. This state is of particular interest because of its quantum-halo character.}, author = {Mark, Michael and Ferlaino, Francesca and Knoop, Steven and Danzl, Johann G and Kraemer, Tobias and Chin, Cheng and Nägerl, Hanns and Grimm, Rudolf}, journal = {Physical Review A - Atomic, Molecular, and Optical Physics}, number = {4}, publisher = {American Physical Society}, title = {{Spectroscopy of ultracold trapped cesium Feshbach molecules}}, doi = {10.1103/PhysRevA.76.042514}, volume = {76}, year = {2007}, } @article{9487, abstract = {Cytosine DNA methylation is considered to be a stable epigenetic mark, but active demethylation has been observed in both plants and animals. In Arabidopsis thaliana, DNA glycosylases of the DEMETER (DME) family remove methylcytosines from DNA. Demethylation by DME is necessary for genomic imprinting, and demethylation by a related protein, REPRESSOR OF SILENCING1, prevents gene silencing in a transgenic background. However, the extent and function of demethylation by DEMETER-LIKE (DML) proteins in WT plants is not known. Using genome-tiling microarrays, we mapped DNA methylation in mutant and WT plants and identified 179 loci actively demethylated by DML enzymes. Mutations in DML genes lead to locus-specific DNA hypermethylation. Reintroducing WT DML genes restores most loci to the normal pattern of methylation, although at some loci, hypermethylated epialleles persist. Of loci demethylated by DML enzymes, >80% are near or overlap genes. Genic demethylation by DML enzymes primarily occurs at the 5′ and 3′ ends, a pattern opposite to the overall distribution of WT DNA methylation. Our results show that demethylation by DML DNA glycosylases edits the patterns of DNA methylation within the Arabidopsis genome to protect genes from potentially deleterious methylation.}, author = {Penterman, Jon and Zilberman, Daniel and Huh, Jin Hoe and Ballinger, Tracy and Henikoff, Steven and Fischer, Robert L.}, issn = {1091-6490}, journal = {Proceedings of the National Academy of Sciences}, number = {16}, pages = {6752--6757}, publisher = {National Academy of Sciences}, title = {{DNA demethylation in the Arabidopsis genome}}, doi = {10.1073/pnas.0701861104}, volume = {104}, year = {2007}, } @misc{9504, author = {Zilberman, Daniel}, booktitle = {Nature Genetics}, issn = {1546-1718}, number = {4}, pages = {442--443}, publisher = {Nature Publishing Group}, title = {{The human promoter methylome}}, doi = {10.1038/ng0407-442}, volume = {39}, year = {2007}, }