@article{12638, abstract = {Central Asian water resources largely depend on melt water generated in the Pamir and Tien Shan mountain ranges. To estimate future water availability in this region, it is necessary to use climate projections to estimate the future glacier extent and volume. In this study, we evaluate the impact of uncertainty in climate change projections on the future glacier extent in the Amu and Syr Darya river basins. To this end we use the latest climate change projections generated for the upcoming IPCC report (CMIP5) and, for comparison, projections used in the fourth IPCC assessment (CMIP3). With these projections we force a regionalized glacier mass balance model, and estimate changes in the basins' glacier extent as a function of the glacier size distribution in the basins and projected temperature and precipitation. This glacier mass balance model is specifically developed for implementation in large scale hydrological models, where the spatial resolution does not allow for simulating individual glaciers and data scarcity is an issue. Although the CMIP5 ensemble results in greater regional warming than the CMIP3 ensemble and the range in projections for temperature as well as precipitation is wider for the CMIP5 than for the CMIP3, the spread in projections of future glacier extent in Central Asia is similar for both ensembles. This is because differences in temperature rise are small during periods of maximum melt (July–September) while differences in precipitation change are small during the period of maximum accumulation (October–February). However, the model uncertainty due to parameter uncertainty is high, and has roughly the same importance as uncertainty in the climate projections. Uncertainty about the size of the decline in glacier extent remains large, making estimates of future Central Asian glacier evolution and downstream water availability uncertain.}, author = {Lutz, A. F. and Immerzeel, W. W. and Gobiet, A. and Pellicciotti, Francesca and Bierkens, M. F. P.}, issn = {1607-7938}, journal = {Hydrology and Earth System Sciences}, keywords = {General Earth and Planetary Sciences, General Engineering, General Environmental Science}, number = {9}, pages = {3661--3677}, publisher = {Copernicus GmbH}, title = {{Comparison of climate change signals in CMIP3 and CMIP5 multi-model ensembles and implications for Central Asian glaciers}}, doi = {10.5194/hess-17-3661-2013}, volume = {17}, year = {2013}, } @article{12639, abstract = {In the headwater catchments of the main Asian rivers, glaciohydrological models are a useful tool to anticipate impacts of climatic changes. However, the reliability of their projections strongly depends on the quality and quantity of data that are available for parameter estimation, model calibration and validation, as well as on the accuracy of climate change projections. In this study the physically oriented, glaciohydrological model TOPKAPI-ETH is used to simulate future changes in snow, glacier, and runoff from the Hunza River Basin in northern Pakistan. Three key sources of model uncertainty in future runoff projections are compared: model parameters, climate projections, and natural climate variability. A novel approach, applicable also to ungauged catchments, is used to determine which model parameters and model components significantly affect the overall model uncertainty. We show that the model is capable of reproducing streamflow and glacier mass balances, but that all analyzed sources of uncertainty significantly affect the reliability of future projections, and that their effect is variable in time and in space. The effect of parametric uncertainty often exceeds the impact of climate uncertainty and natural climate variability, especially in heavily glacierized subcatchments. The results of the uncertainty analysis allow detailed recommendations on network design and the timing and location of field measurements, which could efficiently help to reduce model uncertainty in the future.}, author = {Ragettli, S. and Pellicciotti, Francesca and Bordoy, R. and Immerzeel, W. W.}, issn = {0043-1397}, journal = {Water Resources Research}, keywords = {Water Science and Technology}, number = {9}, pages = {6048--6066}, publisher = {American Geophysical Union}, title = {{Sources of uncertainty in modeling the glaciohydrological response of a Karakoram watershed to climate change}}, doi = {10.1002/wrcr.20450}, volume = {49}, year = {2013}, } @article{12641, abstract = {We investigate the sensitivity of a distributed enhanced temperature-index (ETI) melt model, in order to understand which parameters have the largest influence on model outputs and thus need to be accurately known. We use melt and meteorological data from two Alpine glaciers and one glacier in the Andes of Chile. Sensitivity analysis is conducted in a systematic way in terms of parameters and the different conditions (day, night, clear-sky, overcast), melt seasons and glaciers examined. The sensitivity of total melt to changes in individual parameters is calculated using a local method around the optimal value of the parameters. We verify that the parameters are optimal at the distributed scale and assess the model uncertainty induced by uncertainty in the parameters using a Monte Carlo technique. Model sensitivity to parameters is consistent across melt seasons, glaciers, different conditions and the daily statistics examined. The parameters to which the model is most sensitive are the shortwave-radiation factor, the temperature lapse rate for extrapolation of air temperature, the albedo parameters, the temperature threshold and the cloud transmittance factor parameters. A parameter uncertainty of 5% results in a model uncertainty of 5.6% of mean melt on Haut Glacier d’Arolla, Switzerland.}, author = {Heynen, Martin and Pellicciotti, Francesca and Carenzo, Marco}, issn = {1727-5644}, journal = {Annals of Glaciology}, number = {63}, pages = {311--321}, publisher = {International Glaciological Society}, title = {{Parameter sensitivity of a distributed enhanced temperature-index melt model}}, doi = {10.3189/2013aog63a537}, volume = {54}, year = {2013}, } @article{12642, abstract = {Near-surface air temperature, typically measured at a height of 2 m, is the most important control on the energy exchange and the melt rate at a snow or ice surface. It is distributed in a simplistic manner in most glacier melt models by using constant linear lapse rates, which poorly represent the actual spatial and temporal variability of air temperature. In this paper, we test a simple thermodynamic model proposed by Greuell and Böhm in 1998 as an alternative, using a new dataset of air temperature measurements from along the flowline of Haut Glacier d’Arolla, Switzerland. The unmodified model performs little better than assuming a constant linear lapse rate. When modified to allow the ratio of the boundary layer height to the bulk heat transfer coefficient to vary along the flowline, the model matches measured air temperatures better, and a further reduction of the root-mean-square error is obtained, although there is still considerable scope for improvement. The modified model is shown to perform best under conditions favourable to the development of katabatic winds – few clouds, positive ambient air temperature, limited influence of synoptic or valley winds and a long fetch – but its performance is poor under cloudy conditions.}, author = {Petersen, Lene and Pellicciotti, Francesca and Juszak, Inge and Carenzo, Marco and Brock, Ben}, issn = {1727-5644}, journal = {Annals of Glaciology}, keywords = {Earth-Surface Processes}, number = {63}, pages = {120--130}, publisher = {International Glaciological Society}, title = {{Suitability of a constant air temperature lapse rate over an Alpine glacier: Testing the Greuell and Böhm model as an alternative}}, doi = {10.3189/2013aog63a477}, volume = {54}, year = {2013}, } @article{12643, abstract = {Parameterizations of incoming longwave radiation are increasingly receiving attention for both low and high elevation glacierized sites. In this paper, we test 13 clear-sky parameterizations combined with seven cloud corrections for all-sky atmospheric emissivity at one location on Haut Glacier d'Arolla. We also analyze the four seasons separately and conduct a cross-validation to test the parameters’ robustness. The best parameterization is the one by Dilley and O'Brien, B for clear-sky conditions combined with Unsworth and Monteith cloud correction. This model is also the most robust when tested in cross-validation. When validated at different sites in the southern Alps of Switzerland and north-western Italian Alps, all parameterizations show a substantial decrease in performance, except for one site, thus suggesting that it is important to recalibrate parameterizations of incoming longwave radiation for different locations. We argue that this is due to differences in the structure of the atmosphere at the sites. We also quantify the effect that the incoming longwave radiation parameterizations have on energy-balance melt modeling, and show that recalibration of model parameters is needed. Using parameters from other sites leads to a significant underestimation of melt and to an error that is larger than that associated with using different parameterizations. Once recalibrated, however, the parameters of most models seem to be stable over seasons and years at the location on Haut Glacier d'Arolla.}, author = {Juszak, I. and Pellicciotti, Francesca}, issn = {2169-897X}, journal = {Journal of Geophysical Research: Atmospheres}, keywords = {Space and Planetary Science, Earth and Planetary Sciences (miscellaneous), Atmospheric Science, Geophysics}, number = {8}, pages = {3066--3084}, publisher = {American Geophysical Union}, title = {{A comparison of parameterizations of incoming longwave radiation over melting glaciers: Model robustness and seasonal variability}}, doi = {10.1002/jgrd.50277}, volume = {118}, year = {2013}, } @article{970, abstract = {Recently a new high-mobility Dirac material, trilayer graphene, was realized experimentally. The band structure of ABA-stacked trilayer graphene consists of a monolayer-like and a bilayer-like pair of bands. Here we study electronic properties of ABA-stacked trilayer graphene biased by a perpendicular electric field. We find that the combination of the bias and trigonal warping gives rise to a set of new Dirac points: In each valley, seven species of Dirac fermions with small masses of order of a few meV emerge. The positions and masses of the emergent Dirac fermions are tunable by bias, and one group of Dirac fermions becomes massless at a certain bias value. Therefore, in contrast to bilayer graphene, the conductivity at the neutrality point is expected to show nonmonotonic behavior, becoming of the order of a few e2/h when some Dirac masses vanish. Further, we analyze the evolution of the Landau level spectrum as a function of bias. The emergence of new Dirac points in the band structure translates into new threefold-degenerate groups of Landau levels. This leads to an anomalous quantum Hall effect, in which some quantum Hall steps have a height of 3e2/h. At an intermediate bias, the degeneracies of all Landau levels get lifted, and in this regime all quantum Hall plateaus are spaced by e2/h. Finally, we show that the pattern of Landau level crossings is very sensitive to certain band structure parameters, and can therefore provide a useful tool for determining their precise values.}, author = {Maksym Serbyn and Abanin, Dmitry A}, journal = {Physical Review B - Condensed Matter and Materials Physics}, number = {11}, publisher = {American Physical Society}, title = {{New Dirac points and multiple Landau level crossings in biased trilayer graphene}}, doi = {10.1103/PhysRevB.87.115422}, volume = {87}, year = {2013}, } @article{971, abstract = {We study the stability of the normal state in a mesoscopic NSN junction biased by a constant voltage V with respect to the formation of the superconducting order. Using the linearized time-dependent Ginzburg-Landau equation, we obtain the temperature dependence of the instability line, V inst(T), where nucleation of superconductivity takes place. For sufficiently low biases, a stationary symmetric superconducting state emerges below the instability line. For higher biases, the normal phase is destroyed by the formation of a nonstationary bimodal state with two superconducting nuclei localized near the opposite terminals. The low-temperature and large-voltage behavior of the instability line is highly sensitive to the details of the inelastic relaxation mechanism in the wire. Therefore, experimental studies of Vinst(T) in NSN junctions may be used as an effective tool to access the parameters of the inelastic relaxation in the normal state.}, author = {Maksym Serbyn and Skvortsov, Mikhail A}, journal = {Physical Review B - Condensed Matter and Materials Physics}, number = {2}, publisher = {American Physical Society}, title = {{Onset of superconductivity in a voltage-biased normal-superconducting-normal microbridge}}, doi = {10.1103/PhysRevB.87.020501}, volume = {87}, year = {2013}, } @article{972, abstract = {In topological crystalline insulators (TCIs), topology and crystal symmetry intertwine to create surface states with distinct characteristics. The breaking of crystal symmetry in TCIs is predicted to impart mass to the massless Dirac fermions. Here, we report high-resolution scanning tunneling microscopy studies of a TCI, Pb1-xSnxSe that reveal the coexistence of zero-mass Dirac fermions protected by crystal symmetry with massive Dirac fermions consistent with crystal symmetry breaking. In addition, we show two distinct regimes of the Fermi surface topology separated by a Van-Hove singularity at the Lifshitz transition point. Our work paves the way for engineering the Dirac band gap and realizing interaction-driven topological quantum phenomena in TCIs.}, author = {Okada, Yoshinori and Serbyn, Maksym and Lin, Hsin and Walkup, Daniel and Zhou, Wenwen and Dhital, Chetan and Neupane, Madhab and Xu, Suyang and Wang, Yungjui and Sankar, Raman and Chou, Fangcheng and Bansil, Arun and Hasan, Md and Wilson, Stephen and Fu, Liang and Madhavan, Vidya}, journal = {Science}, number = {6153}, pages = {1496 -- 1499}, publisher = {American Association for the Advancement of Science}, title = {{Observation of dirac node formation and mass acquisition in a topological crystalline insulator}}, doi = {10.1126/science.1239451}, volume = {341}, year = {2013}, } @article{973, abstract = {We construct a complete set of local integrals of motion that characterize the many-body localized (MBL) phase. Our approach relies on the assumption that local perturbations act locally on the eigenstates in the MBL phase, which is supported by numerical simulations of the random-field XXZ spin chain. We describe the structure of the eigenstates in the MBL phase and discuss the implications of local conservation laws for its nonequilibrium quantum dynamics. We argue that the many-body localization can be used to protect coherence in the system by suppressing relaxation between eigenstates with different local integrals of motion.}, author = {Maksym Serbyn and Papić, Zlatko and Abanin, Dmitry A}, journal = {Physical Review Letters}, number = {12}, publisher = {American Physical Society}, title = {{Local conservation laws and the structure of the many body localized states}}, doi = {10.1103/PhysRevLett.111.127201}, volume = {111}, year = {2013}, } @article{974, abstract = {We propose a possible realization of the overscreened Kondo impurity problem by a magnetic s=1/2 impurity embedded in a two-dimensional S=1 U(1) spin liquid with a Fermi surface. This problem contains an interesting interplay between non-Fermi-liquid behavior induced by a U(1) gauge field coupled to fermions and a non-Fermi-liquid fixed point in the overscreened Kondo problem. Using a large-N expansion together with an expansion in the dynamical exponent of the gauge field, we find that the coupling to the gauge field leads to weak but observable changes in the physical properties of the system at the overscreened Kondo fixed point. We discuss the extrapolation of this result to a physical case and argue that the realization of overscreened Kondo physics could lead to observations of effects due to gauge fields.}, author = {Serbyn, Maksym and Senthil, Todadri and Lee, Patrick}, journal = {Physical Review B - Condensed Matter and Materials Physics}, number = {2}, publisher = {American Physical Society}, title = {{Overscreened Kondo fixed point in S=1 spin liquid}}, doi = {10.1103/PhysRevB.88.024419}, volume = {88}, year = {2013}, } @article{975, abstract = {Recent numerical work by Bardarson, Pollmann, and Moore revealed a slow, logarithmic in time, growth of the entanglement entropy for initial product states in a putative many-body localized phase. We show that this surprising phenomenon results from the dephasing due to exponentially small interaction-induced corrections to the eigenenergies of different states. For weak interactions, we find that the entanglement entropy grows as ξln (Vt/), where V is the interaction strength, and ξ is the single-particle localization length. The saturated value of the entanglement entropy at long times is determined by the participation ratios of the initial state over the eigenstates of the subsystem. Our work shows that the logarithmic entanglement growth is a universal phenomenon characteristic of the many-body localized phase in any number of spatial dimensions, and reveals a broad hierarchy of dephasing time scales present in such a phase.}, author = {Maksym Serbyn and Papić, Zlatko and Abanin, Dmitry A}, journal = {Physical Review Letters}, number = {26}, publisher = {American Physical Society}, title = {{Universal slow growth of entanglement in interacting strongly disordered systems}}, doi = {10.1103/PhysRevLett.110.260601}, volume = {110}, year = {2013}, } @misc{9751, abstract = {High relatedness among interacting individuals has generally been considered a precondition for the evolution of altruism. However, kin-selection theory also predicts the evolution of altruism when relatedness is low, as long as the cost of the altruistic act is minor compared to its benefit. Here, we demonstrate evidence for a low-cost altruistic act in bacteria. We investigated Escherichia coli responding to the attack of an obligately lytic phage by committing suicide in order to prevent parasite transmission to nearby relatives. We found that bacterial suicide provides large benefits to survivors at marginal costs to committers. The cost of suicide was low because infected cells are moribund, rapidly dying upon phage infection, such that no more opportunity for reproduction remains. As a consequence of its marginal cost, host suicide was selectively favoured even when relatedness between committers and survivors approached zero. Altogether, our findings demonstrate that low-cost suicide can evolve with ease, represents an effective host-defence strategy, and seems to be widespread among microbes. Moreover, low-cost suicide might also occur in higher organisms as exemplified by infected social insect workers leaving the colony to die in isolation.}, author = {Refardt, Dominik and Bergmiller, Tobias and Kümmerli, Rolf}, publisher = {Dryad}, title = {{Data from: Altruism can evolve when relatedness is low: evidence from bacteria committing suicide upon phage infection}}, doi = {10.5061/dryad.b1q2n}, year = {2013}, } @misc{9754, abstract = {Short-read sequencing technologies have in principle made it feasible to draw detailed inferences about the recent history of any organism. In practice, however, this remains challenging due to the difficulty of genome assembly in most organisms and the lack of statistical methods powerful enough to discriminate among recent, non-equilibrium histories. We address both the assembly and inference challenges. We develop a bioinformatic pipeline for generating outgroup-rooted alignments of orthologous sequence blocks from de novo low-coverage short-read data for a small number of genomes, and show how such sequence blocks can be used to fit explicit models of population divergence and admixture in a likelihood framework. To illustrate our approach, we reconstruct the Pleistocene history of an oak-feeding insect (the oak gallwasp Biorhiza pallida) which, in common with many other taxa, was restricted during Pleistocene ice ages to a longitudinal series of southern refugia spanning theWestern Palaearctic. Our analysis of sequence blocks sampled from a single genome from each of three major glacial refugia reveals support for an unexpected history dominated by recent admixture. Despite the fact that 80% of the genome is affected by admixture during the last glacial cycle, we are able to infer the deeper divergence history of these populations. These inferences are robust to variation in block length, mutation model, and the sampling location of individual genomes within refugia. This combination of de novo assembly and numerical likelihood calculation provides a powerful framework for estimating recent population history that can be applied to any organism without the need for prior genetic resources.}, author = {Hearn, Jack and Stone, Graham and Barton, Nicholas H and Lohse, Konrad and Bunnefeld, Lynsey}, publisher = {Dryad}, title = {{Data from: Likelihood-based inference of population history from low coverage de novo genome assemblies}}, doi = {10.5061/dryad.r3r60}, year = {2013}, } @article{976, abstract = {Motivated by a search for experimental probes to access the physics of fractionalized excitations called spinons in spin liquids, we study the interaction of spinons with lattice vibrations. We consider the case of algebraic spin liquid, when spinons have fermionic statistics and a Dirac-like dispersion. We establish the general procedure for deriving spinon-phonon interactions, which is based on symmetry considerations. The procedure is illustrated for four different algebraic spin liquids: π-flux and staggered-flux phases on a square lattice, π-flux phase on a kagome lattice, and zero-flux phase on a honeycomb lattice. Although the low-energy description is similar for all these phases, different underlying symmetry groups lead to a distinct form of spinon-phonon interaction Hamiltonian. The explicit form of the spinon-phonon interaction is used to estimate the attenuation of ultrasound in an algebraic spin liquid. The prospects of the sound attenuation as a probe of spinons are discussed.}, author = {Maksym Serbyn and Lee, Patrick}, journal = {Physical Review B - Condensed Matter and Materials Physics}, number = {17}, publisher = {American Physical Society}, title = {{Spinon-phonon interaction in algebraic spin liquids}}, doi = {10.1103/PhysRevB.87.174424}, volume = {87}, year = {2013}, } @article{344, abstract = {Copper-based selenides are attracting increasing interest due to their outstanding optoelectronic and thermoelectric properties. Herein a novel colloidal synthetic route to prepare Cu2SnSe3 nanocrystals with controlled size, shape and composition is presented. The high yield of the developed procedure allowed its up-scaling to the production of grams of colloidal Cu2SnSe3 nanocrystals. These nanocrystals were used as building blocks for the production of Cu2SnSe3 bulk nanostructured materials by spark plasma sintering. The thermoelectric properties of the prepared nanocrystalline Cu2SnSe3 pellets were characterized in the temperature range from 300 to 720 K. The obtained results show the bottom-up production of nanocrystalline materials from solution-processed nanocrystals to be a potentially advantageous alternative to conventional methods of production of efficient thermoelectric materials.}, author = {Ibáñez, Maria and Cadavid, Doris and Anselmi Tamburini, Umberto and Zamani, Reza and Gorsse, Stéphane and Li, Wenhua and López, Antonio and Morante, Joan and Arbiol, Jordi and Cabot, Andreu}, journal = {Journal of Materials Chemistry A}, number = {4}, pages = {1421 -- 1426}, publisher = {Royal Society of Chemistry}, title = {{Colloidal synthesis and thermoelectric properties of Cu 2SnSe3 nanocrystals}}, doi = {10.1039/C2TA00419D}, volume = {1}, year = {2013}, } @article{450, abstract = {Understanding the relative importance of heterosis and outbreeding depression over multiple generations is a key question in evolutionary biology and is essential for identifying appropriate genetic sources for population and ecosystem restoration. Here we use 2455 experimental crosses between 12 population pairs of the rare perennial plant Rutidosis leptorrhynchoides (Asteraceae) to investigate the multi-generational (F1, F2, F3) fitness outcomes of inter-population hybridization. We detected no evidence of outbreeding depression, with inter-population hybrids and backcrosses showing either similar fitness or significant heterosis for fitness components across the three generations. Variation in heterosis among population pairs was best explained by characteristics of the foreign source or home population, and was greatest when the source population was large, with high genetic diversity and low inbreeding, and the home population was small and inbred. Our results indicate that the primary consideration for maximizing progeny fitness following population augmentation or restoration is the use of seed from large, genetically diverse populations.}, author = {Pickup, Melinda and Field, David and Rowell, David and Young, Andrew}, journal = {Proceedings of the Royal Society of London Series B Biological Sciences}, number = {1750}, publisher = {Royal Society, The}, title = {{Source population characteristics affect heterosis following genetic rescue of fragmented plant populations}}, doi = {10.1098/rspb.2012.2058}, volume = {280}, year = {2013}, } @article{244, abstract = {We investigate the solubility of the congruence xy ≡ 1 (mod p), where p is a prime and x, y are restricted to lie in suitable short intervals. Our work relies on a mean value theorem for incomplete Kloosterman sums.}, author = {Timothy Browning and Haynes, Alan K}, journal = {International Journal of Number Theory}, number = {2}, pages = {481 -- 486}, publisher = {World Scientific Publishing}, title = {{Incomplete kloosterman sums and multiplicative inverses in short intervals}}, doi = { https://doi.org/10.1142/S1793042112501448}, volume = {9}, year = {2012}, } @article{2459, abstract = {Coordinated, subcellular trafficking of proteins is one of the fundamental properties of the multicellular eukaryotic organisms. Trafficking involves a large diversity of compartments, pathways, cargo molecules, and vesicle-sorting events. It is also crucial in regulating the localization and, thus, the activity of various proteins, but the process is still poorly genetically defined in plants. In the past, forward genetics screens had been used to determine the function of genes by searching for a specific morphological phenotype in the organism population in which mutations had been induced chemically or by irradiation. Unfortunately, these straightforward genetic screens turned out to be limited in identifying new regulators of intracellular protein transport, because mutations affecting essential trafficking pathways often lead to lethality. In addition, the use of these approaches has been restricted by functional redundancy among trafficking regulators. Screens for mutants that rely on the observation of changes in the cellular localization or dynamics of fluorescent subcellular markers enable, at least partially, to circumvent these issues. Hence, such image-based screens provide the possibility to identify either alleles with weak effects or components of the subcellular trafficking machinery that have no strong impact on the plant growth.}, author = {Zwiewka, Marta and Friml, Jirí}, journal = {Frontiers in Plant Science}, number = {May}, publisher = {Frontiers Research Foundation}, title = {{Fluorescence imaging-based forward genetic screens to identify trafficking regulators in plants}}, doi = {10.3389/fpls.2012.00097}, volume = {3}, year = {2012}, } @unpublished{2696, author = {László Erdös}, booktitle = {ArXiv}, publisher = {ArXiv}, title = {{Universality for random matrices and log-gases}}, year = {2012}, } @inproceedings{2700, author = {László Erdös}, pages = {3 -- 98}, publisher = {Oxford University Press}, title = {{Lecture notes on quantum Brownian motion}}, volume = {95}, year = {2012}, }