Online Maximum k-Coverage

We study an online model for the maximum k-vertex-coverage problem, where given a graph G = (V,E) and an integer k, we ask for a subset A ⊆ V, such that |A | = k and the number of edges covered by A is maximized. In our model, at each step i, a new vertex vi is revealed, and we have to decide whether we will keep it or discard it. At any time of the process, only k vertices can be kept in memory; if at some point the current solution already contains k vertices, any inclusion of any new vertex in the solution must entail the irremediable deletion of one vertex of the current solution (a vertex not kept when revealed is irremediably deleted). We propose algorithms for several natural classes of graphs (mainly regular and bipartite), improving on an easy 1/2-competitive ratio. We next settle a set-version of the problem, called maximum k-(set)-coverage problem. For this problem we present an algorithm that improves upon former results for the same model for small and moderate values of k

Multi-Epoch Analysis of a Satellite Constellation to Identify Value Robust Deployment across Uncertain Futures

The value of a system depends heavily on the future contexts it will encounter. For complex space systems with multi-year design and deployment phases, it is useful to design a system so that it delivers value to stakeholders over a wide range of future contexts. Epoch-Era Analysis, a computational scenario planning approach, decomposes the lifecycle of a system into sequential epochs that each have fixed contexts and value expectations. This paper applies Multi-Epoch Analysis (a subset of Epoch-Era Analysis) along with Multi-Attribute Tradespace Exploration (MATE) to the design of a satellite constellation, with the aim of maximizing value across a range of end-user subscription and geographic distribution contexts. The system level tradespace is assembled using a bottom-up iterative approach based on expert knowledge, and accounts for performance attributes metrics such as revisit times, data latencies, observation times, and data downlink volumes. Competing designs consisting of alternative orbital, ground station location, and deployment configurations are evaluated in terms of their fuzzy Normalized Pareto Trace (fNPT) across epochs. The resulting staged deployment strategy delivers robust value based on stakeholder preference across a wide range of future contexts. Nomenclature DZ = deployment design variable index Z fNPT = fuzzy normalized pareto trace GY = ground station design variable index Y K = fuzziness factor MAU = multi-attribute utility NPT = normalized pareto trace OX = orbit design variable index X I

Induced spin orbit splitting in graphene the role of atomic number of the intercalated metal and pi d hybridization

This paper reports spin dependent valence band dispersions of graphene synthesized on Ni 111 and subsequently intercalated with monolayers of Au, Cu and Bi. We have previously shown that after intercalation of graphene with Au the dispersion of the band remains linear in the region of the K point of the surface Brillouin zone even though the system exhibits a noticeable hybridization between states of graphene and d states of Au. We have also demonstrated a giant spin orbit splitting of states in Au intercalated graphene which can reach up to 100 meV. In this paper we probe in detail dispersions of graphene Au d hybridized bands. We show that intercalation of Cu does not produce a noticeable spin orbit splitting in graphene although this system, similarly to Au intercalated graphene, also reveals hybridization between graphene states and d states of Cu. To clarify the role of intercalated Au, the electronic and spin structures of Au monolayers on Ni 111 are comparatively studied with and without graphene on top and the importance of the spin splitting of the d states of the intercalated material is established.These Au d states in graphene Au Ni 111 are further studied in detail by spinand angle resolved photoemission, and spin dependent hybridization between graphene and Au bands is revealed. In contrast, intercalation of the sp metal Bi, despite its high atomic number, does not lead to any measurable spin orbit splitting of the states of graphene. This means that for the creation of large spin orbit splitting in graphene, neither hybridization with d states as with Cu nor the high atomic number of the intercalated material alone as with Bi is sufficient, and a combination of them is required as with A

Mapping and characterization of structural variation in 17,795 human genomes

A key goal of whole-genome sequencing for studies of human genetics is to interrogate all forms of variation, including single-nucleotide variants, small insertion or deletion (indel) variants and structural variants. However, tools and resources for the study of structural variants have lagged behind those for smaller variants. Here we used a scalable pipeline1 to map and characterize structural variants in 17,795 deeply sequenced human genomes. We publicly release site-frequency data to create the largest, to our knowledge, whole-genome-sequencing-based structural variant resource so far. On average, individuals carry 2.9 rare structural variants that alter coding regions; these variants affect the dosage or structure of 4.2 genes and account for 4.0–11.2% of rare high-impact coding alleles. Using a computational model, we estimate that structural variants account for 17.2% of rare alleles genome-wide, with predicted deleterious effects that are equivalent to loss-of-function coding alleles; approximately 90% of such structural variants are noncoding deletions (mean 19.1 per genome). We report 158,991 ultra-rare structural variants and show that 2% of individuals carry ultra-rare megabase-scale structural variants, nearly half of which are balanced or complex rearrangements. Finally, we infer the dosage sensitivity of genes and noncoding elements, and reveal trends that relate to element class and conservation. This work will help to guide the analysis and interpretation of structural variants in the era of whole-genome sequencing

Novel Loci for Adiponectin Levels and Their Influence on Type 2 Diabetes and Metabolic Traits : A Multi-Ethnic Meta-Analysis of 45,891 Individuals

J. Kaprio, S. Ripatti ja M.-L. Lokki työryhmien jäseniä.Peer reviewe

Induced Rashba splitting of electronic states in monolayers of Au, Cu on a W 110 substrate

The paper sums up a theoretical and experimental investigation of the influence of the spin orbit coupling in W 110 on the spin structure of electronic states in deposited Au and Cu monolayers. Angle resolved photoemission spectroscopy reveals that in the case of monolayers of Au and Cu spin orbit split bands are formed in a surface projected gap of W 110 . Spin resolution shows that these states are spin polarized and that, therefore, the spin orbit splitting is of Rashba type. The states evolve from hybridization of W 5d, 6p derived states with the s, p states of the deposited metal. Interaction with Au and Cu shifts the original W 5d derived states from the edges toward the center of the surface projected gap. The size of the spin orbit splitting of the formed states does not correlate with the atomic number of the deposited metal and is even higher for Cu than for Au. These states can be described as W derived surface resonances modified by hybridization with the p, d states of the adsorbed metal. Our electronic structure calculations performed in the framework of the density functional theory correlate well with the experiment and demonstrate the crucial role of the W top layer for the spin orbit splitting. It is shown that the contributions of the spin orbit interaction from W and Au act in opposite directions which leads to a decrease of the resulting spin orbit splitting in the Au monolayer on W 110 . For the Cu monolayer with lower spin orbit interaction the resulting spin splitting is higher and mainly determined by the