Linear-Time Algorithms for Geometric Graphs with Sublinearly Many Edge Crossings

We provide linear-time algorithms for geometric graphs with sublinearly many crossings. That is, we provide algorithms running in O(n) time on connected geometric graphs having n vertices and k crossings, where k is smaller than n by an iterated logarithmic factor. Specific problems we study include Voronoi diagrams and single-source shortest paths. Our algorithms all run in linear time in the standard comparison-based computational model; hence, we make no assumptions about the distribution or bit complexities of edge weights, nor do we utilize unusual bit-level operations on memory words. Instead, our algorithms are based on a planarization method that "zeroes in" on edge crossings, together with methods for extending planar separator decompositions to geometric graphs with sublinearly many crossings. Incidentally, our planarization algorithm also solves an open computational geometry problem of Chazelle for triangulating a self-intersecting polygonal chain having n segments and k crossings in linear time, for the case when k is sublinear in n by an iterated logarithmic factor.Comment: Expanded version of a paper appearing at the 20th ACM-SIAM Symposium on Discrete Algorithms (SODA09

Media

Diplomová práce "Média jako zprostředkovatel národního sebevědomí: analýza vítězství československých hokejistů na mistrovství světa 1947" se věnuje reflekci významné sportovní události v médiích a předpokládaným dopadům na publikum. Cílem této diplomové práce je popsat vztah mezi mediálními obsahy a národním sebevědomím a posoudit, jak média referovala o úspěchu československých hokejistů na mistrovství světa 1947. Na základě odborné literatury a předložených teoretických konceptů jsem stanovil hypotézu, že média se po 2. světové válce aktivně podílela na formování národního sebevědomí a posilování národní identity. Druhou hypotézu jsem zformuloval okolo konceptu eskapické funkce médií a tvrzení, že mediální obsahy referující o mistrovství světa vedly k aktivní odezvě u čtenářů. K tomuto účelu jsem srovnávací studii podrobil tři vybrané deníkové tituly: Lidovou demokracii, Rudé Právo a deník Práce. Předtím, než jsem začal tyto tituly analyzovat, zasadil jsem dobu konání mistrovství světa do historického kontextu s politickými i mediálními souvislostmi. Samotná analýza obsahů z vybraného období probíhala na základě bohatého teoretického rámce, v němž jsem popsal způsoby, jakými média působí na publikum, i důvody, proč publikum média užívá. Na závěr této diplomové práce předkládám konkrétní poznatky...Diploma thesis "Media as an Agent of National Self-Confidence: Analysis of the Victory of the Czechoslovak Ice Hockey Players at the 1947 World Championship" deals with the reflection of the major sport event in the Czechoslovak media and how this reflection inspired the audience. The goal of this diploma thesis is to describe the dependance between the media coverage and the national self-confidence, which results from the national identity. Therefore, I focused on the chosen newspaper titles to analyze the content they produced during the 1947 Ice Hockey World Championship. I defined a hypothesis, based on observation and scholarly literature, that the media used the coverage to strengthen the national self-confidence and redefine the national identity. My second hypothesis was the idea, that this kind of coverage led to an active response among the audience. Before I started analyzing the three chosen titles (Lidova demokracie, Rude Pravo, Prace), I delivered complex structure of theoretical concepts, describing the influence media have towards the audience and also reasons why the members of the audience use media in their everyday life. I also focused on the historical and political context, as well as the media landscape that shaped the content of that time. I conducted the analysis and...Department of Media StudiesKatedra mediálních studiíFaculty of Social SciencesFakulta sociálních vě

Gender diversity in management

Tato práce řešila téma genderové rozdílnosti na trhu práce v České republice, neboť jde o hojně diskutovanou problematiku. Práce měla za cíl problematiku nastínit a více přiblížit laické veřejnosti. Práce je rozdělena do dvou hlavních částí, seznámení s teoretickým vymezením genderové diverzity, porovnání ženských a mužských stylů řízení, popsat rozdíly v odměňování mužů a žen za stejně vykonanou práci. Praktická část je zaměřena na průzkum ve třiceti firmách působících na území České republiky s porovnáním zastoupení žen a mužů manažerů v jednotlivých společnosti a vliv žen manažerek na finanční výkon těchto firem. Praktická část práce využívala dat z veřejných portálů a databází Českého statistického úřadu, Justice a Orbisu. Hlavním výstupem praktické části práce je odpověď na otázku, zda ženy zastoupené ve vysokých manažerských pozicích ovlivňují finanční výsledek, tedy finanční ukazatele firem. Na otázku není možné dát jednoznačnou odpověď, neboť ji ovlivňuje několik aspektů.ObhájenoThis thesis addressed the topic of gender differences within the labour market in the Czech Republic, as it is a widely discussed issue. The aim of the work was to outline the issue and bring it closer to the general public. The thesis is divided into two main parts, introduction to the theoretical definition of gender diversity, comparison of female and male management styles, describe the differences in the reward system of men and women for the same work done. The practical part is focused on a survey in thirty companies operating in the Czech Republic with a comparison of women´s and men´s representation in management in different companies and the influence of female managers on the financial performance within these companies. The thesis´s practical part used data from public portals and databases of the Czech Statistical Office, Justice and Orbis. The main output of the thesis´s practical part is to answer the question whether women represented in high management positions influence the financial result, i.e., the financial indicators of the companies. It is impossible to give a clear answer to the question, as it is influenced by several aspects

Enzymatic activity and immunoreactivity of Aca s 4, an alpha-amylase allergen from the storage mite Acarus siro

<p>Abstract</p> <p>Background</p> <p>Enzymatic allergens of storage mites that contaminate stored food products are poorly characterized. We describe biochemical and immunological properties of the native alpha-amylase allergen Aca s 4 from <it>Acarus siro</it>, a medically important storage mite.</p> <p>Results</p> <p><it>A. siro </it>produced a high level of alpha-amylase activity attributed to Aca s 4. This enzyme was purified and identified by protein sequencing and LC-MS/MS analysis. Aca s 4 showed a distinct inhibition pattern and an unusual alpha-amylolytic activity with low sensitivity to activation by chloride ions. Homology modeling of Aca s 4 revealed a structural change in the chloride-binding site that may account for this activation pattern. Aca s 4 was recognized by IgE from house dust mite-sensitive patients, and potential epitopes for cross-reactivity with house dust mite group 4 allergens were found.</p> <p>Conclusions</p> <p>We present the first protein-level characterization of a group 4 allergen from storage mites. Due to its high production and IgE reactivity, Aca s 4 is potentially relevant to allergic hypersensitivity.</p

Dynamics of digestive proteolytic system during blood feeding of the hard tick Ixodes ricinus

<p>Abstract</p> <p>Background</p> <p>Ticks are vectors of a wide variety of pathogens causing severe diseases in humans and domestic animals. Intestinal digestion of the host blood is an essential process of tick physiology and also a limiting factor for pathogen transmission since the tick gut represents the primary site for pathogen infection and proliferation. Using the model tick <it>Ixodes ricinus</it>, the European Lyme disease vector, we have previously demonstrated by genetic and biochemical analyses that host blood is degraded in the tick gut by a network of acidic peptidases of the aspartic and cysteine classes.</p> <p>Results</p> <p>This study reveals the digestive machinery of the <it>I. ricinus </it>during the course of blood-feeding on the host. The dynamic profiling of concentrations, activities and mRNA expressions of the major digestive enzymes demonstrates that the <it>de novo </it>synthesis of peptidases triggers the dramatic increase of the hemoglobinolytic activity along the feeding period. Overall hemoglobinolysis, as well as the activity of digestive peptidases are negligible at the early stage of feeding, but increase dramatically towards the end of the slow feeding period, reaching maxima in fully fed ticks. This finding contradicts the established opinion that blood digestion is reduced at the end of engorgement. Furthermore, we show that the digestive proteolysis is localized intracellularly throughout the whole duration of feeding.</p> <p>Conclusions</p> <p>Results suggest that the egressing proteolytic system in the early stage of feeding and digestion is a potential target for efficient impairment, most likely by blocking its components via antibodies present in the host blood. Therefore, digestive enzymes are promising candidates for development of novel 'anti-tick' vaccines capable of tick control and even transmission of tick-borne pathogens.</p

Medium effects in K^+ nucleus interaction from consistent analysis of integral and differential cross sections

Self consistency in the analysis of transmission measurements for K^+ on several nuclei in the momentum range of 500-700 MeV/c is achieved with a "t_{eff}(rho)rho" potential and new results are derived for total cross sections. The imaginary part of the t_{eff} amplitude is found to increase linearly with the average nuclear density in excess of a threshold value. This phenomenological density dependence of the K^+ nucleus optical potential also gives rise to good agreement with recent measurements of differential cross sections for elastic scattering of 715 MeV/c K^+ by Li^6 and C.Comment: 11 pages, RevTeX, 2 Postscript figures, submitted Phys. Lett.

Profiling of proteolytic enzymes in the gut of the tick Ixodes ricinus reveals an evolutionarily conserved network of aspartic and cysteine peptidases

<p>Abstract</p> <p>Background</p> <p>Ticks are vectors for a variety of viral, bacterial and parasitic diseases in human and domestic animals. To survive and reproduce ticks feed on host blood, yet our understanding of the intestinal proteolytic machinery used to derive absorbable nutrients from the blood meal is poor. Intestinal digestive processes are limiting factors for pathogen transmission since the tick gut presents the primary site of infection. Moreover, digestive enzymes may find practical application as anti-tick vaccine targets.</p> <p>Results</p> <p>Using the hard tick, <it>Ixodes ricinus</it>, we performed a functional activity scan of the peptidase complement in gut tissue extracts that demonstrated the presence of five types of peptidases of the cysteine and aspartic classes. We followed up with genetic screens of gut-derived cDNA to identify and clone genes encoding the cysteine peptidases cathepsins B, L and C, an asparaginyl endopeptidase (legumain), and the aspartic peptidase, cathepsin D. By RT-PCR, expression of asparaginyl endopeptidase and cathepsins B and D was restricted to gut tissue and to those developmental stages feeding on blood.</p> <p>Conclusion</p> <p>Overall, our results demonstrate the presence of a network of cysteine and aspartic peptidases that conceivably operates to digest host blood proteins in a concerted manner. Significantly, the peptidase components of this digestive network are orthologous to those described in other parasites, including nematodes and flatworms. Accordingly, the present data and those available for other tick species support the notion of an evolutionary conservation of a cysteine/aspartic peptidase system for digestion that includes ticks, but differs from that of insects relying on serine peptidases.</p

SmSP2: A serine protease secreted by the blood fluke pathogen Schistosoma mansoni with anti-hemostatic properties.

BackgroundSerine proteases are important virulence factors for many pathogens. Recently, we discovered a group of trypsin-like serine proteases with domain organization unique to flatworm parasites and containing a thrombospondin type 1 repeat (TSR-1). These proteases are recognized as antigens during host infection and may prove useful as anthelminthic vaccines, however their molecular characteristics are under-studied. Here, we characterize the structural and proteolytic attributes of serine protease 2 (SmSP2) from Schistosoma mansoni, one of the major species responsible for the tropical infectious disease, schistosomiasis.Methodology/principal findingsSmSP2 comprises three domains: a histidine stretch, TSR-1 and a serine protease domain. The cleavage specificity of recombinant SmSP2 was determined using positional scanning and multiplex combinatorial libraries and the determinants of specificity were identified with 3D homology models, demonstrating a trypsin-like endopeptidase mode of action. SmSP2 displayed restricted proteolysis on protein substrates. It activated tissue plasminogen activator and plasminogen as key components of the fibrinolytic system, and released the vasoregulatory peptide, kinin, from kininogen. SmSP2 was detected in the surface tegument, esophageal glands and reproductive organs of the adult parasite by immunofluorescence microscopy, and in the excretory/secretory products by immunoblotting.Conclusions/significanceThe data suggest that SmSP2 is secreted, functions at the host-parasite interface and contributes to the survival of the parasite by manipulating host vasodilatation and fibrinolysis. SmSP2 may be, therefore, a potential target for anti-schistosomal therapy

Centrality evolution of the charged-particle pseudorapidity density over a broad pseudorapidity range in Pb-Pb collisions at root s(NN)=2.76TeV

Peer reviewe

The ALICE experiment at the CERN LHC

ALICE (A Large Ion Collider Experiment) is a general-purpose, heavy-ion detector at the CERN LHC which focuses on QCD, the strong-interaction sector of the Standard Model. It is designed to address the physics of strongly interacting matter and the quark-gluon plasma at extreme values of energy density and temperature in nucleus-nucleus collisions. Besides running with Pb ions, the physics programme includes collisions with lighter ions, lower energy running and dedicated proton-nucleus runs. ALICE will also take data with proton beams at the top LHC energy to collect reference data for the heavy-ion programme and to address several QCD topics for which ALICE is complementary to the other LHC detectors. The ALICE detector has been built by a collaboration including currently over 1000 physicists and engineers from 105 Institutes in 30 countries. Its overall dimensions are 161626 m3 with a total weight of approximately 10 000 t. The experiment consists of 18 different detector systems each with its own specific technology choice and design constraints, driven both by the physics requirements and the experimental conditions expected at LHC. The most stringent design constraint is to cope with the extreme particle multiplicity anticipated in central Pb-Pb collisions. The different subsystems were optimized to provide high-momentum resolution as well as excellent Particle Identification (PID) over a broad range in momentum, up to the highest multiplicities predicted for LHC. This will allow for comprehensive studies of hadrons, electrons, muons, and photons produced in the collision of heavy nuclei. Most detector systems are scheduled to be installed and ready for data taking by mid-2008 when the LHC is scheduled to start operation, with the exception of parts of the Photon Spectrometer (PHOS), Transition Radiation Detector (TRD) and Electro Magnetic Calorimeter (EMCal). These detectors will be completed for the high-luminosity ion run expected in 2010. This paper describes in detail the detector components as installed for the first data taking in the summer of 2008