6,684 research outputs found

    Monte Carlo event generation of photon-photon collisions at colliders

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    In addition to being interesting in itself, the photon-photon interactions will be an inevitable background for the future electron-positron colliders. Thus to be able to quantify the potential of future electron-positron colliders it is important to have an accurate description of these collisions. Here we present our ongoing work to implement the photon-photon collisions in the Pythia 8 event generator. First we introduce photon PDFs in general and then discuss in more detail one particular set we have used in our studies. Then we will discuss how the parton-shower algorithm in Pythia 8 is modified in case of photon beams and how the beam remnants are constructed. Finally a brief outlook on future developments is given.Comment: Talk presented at PHOTON2015 conference, June 15 - 19, 2015, Budker Institute of Nuclear Physics (BINP), Siberian Branch of Russian Academy of Science, Novosibirsk, Russi

    Theme city or gated community - images of future cities

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    The future of the cities has been under discussion since the first city. It has been typical in every civilisation and era to hope for a better city. Creek philosopher Platon created image of future city where all men were equal and the city was ruled by philosophers minds. Many philosopher or later social scientist have ended up to similar "hope to be city". The form and type of the better city has depended from creators of those future city images. The creators have had their future city images made through their own political, ideological, religious or other principles. In the recent discussion on the national or international level it has been common to have those images of the future cities divided in only two categories: "it''s gonna be either small or big city", "it''s gonna be either well balanced or polarising city development", "it''s gonna be either dying or competitive city", etc. The varying images of future cities are missed but yet still not noticed. The future of the cities is made by varying creators/factors/composers. Happening development is to be made by common evolution of societies, changing structures of infrastructure, public sector and work, international trades and markets, or natural catastrophes or wars. Or they are made by cities (their managers, developers, citizens, city marketing units, etc.) themselves. The images of future cities can be developed by many ways. These images are born in the minds of common people while they follow the ongoing evolution of the globe, nations, nature, cities etc. - both in international and local level. Or the images of future cities are made especially for some particular purpose. Movies such as "Matrix", "Blade Runner" and "12 Monkeys" present their writers and directors view to the possible future. City marketing units try to create fancy images of their city now and in the future - when all the aims of the city developers are to be full fill the needs of the most wanted citizens. The aim of the paper is to present six different type of possible future cities: "Theme city", "Urban village", "Gated community", "Multicultural city", "Network city" and "Ecological city". There are many more future images of the cities presented in studies of the cities and in other literature. These six different city types are introduced shortly - basic elements and features.

    Electron-Ion Physics with the LHeC

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    The Large Hadron Electron Collider (LHeC) project is the proposal to use the existing LHC proton/ion beams and construct a new electron beam line to perform high-energy electron-proton/ion collisions. In this talk, we consider some of the physics topics that could be studied in the electron-ion mode. In particular, we estimate how much the current nuclear parton distribution fits could be improved with the deeply inelastic scattering measurements at the LHeC by including pseudodata into a global analysis. In addition, we discuss briefly other topics that would help to better understand some aspects of heavy-ion collisions, namely small-xx physics and hadron production with a nuclear target.Comment: Talk presented at DIS2015 conference, April 27 - May 1, 2015, Southern Methodist University, Dallas, Texas. v2: Updated reference lis

    nPDF constraints from the Large Hadron Electron Collider

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    An updated analysis regarding the expected nuclear PDF constraints from the future Large Hadron Electron Collider (LHeC) experiment is presented. The new study is based on a more flexible small-xx parametrization which provides less biased uncertainty estimates in the region where there are currently no data constraints. The effect of the LHeC is quantified by directly including a sample of pseudodata according to the expected precision of this planned experiment. As a result, a significant reduction of the small-xx uncertainties in sea quarks and gluons is observed.Comment: Talk presented at DIS2016 conference, April 11 - April 15, 2016, DESY, Hamburg, German

    Plant communities of field boundaries in Finnish farmland

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    To determine the importance of field boundary habitats for farmland biodiversity, we surveyed a total of 193 boundaries from four climatically and agriculturally dissimilar regions in Finland. We measured the current plant species richness and composition of the boundaries, and based on the differences in vegetation characteristics, we describe six boundary types. The observed plant species were mainly indicators of fresh to wet soils and moderate to rich mineral nitrogen content. The most frequent species were tall, perennial monocots and dicots indicating the high productivity of thevegetation. Moreove, herbicide-tolerant species were common. No species rare for Finland were found.In animal husbandry regions, the most frequent species were sown grassland species and typical grassland weeds. In cereal production regions, fast-spreading root weeds tolerant of herbicides were the most frequent. Mean species richness was highest in the cluster Ca-lamagrostis-Phalaris (24 species (s)/boundary (b)), which we considered as representative of moist sites with some disturbance by agricultural practices. Most species-poor were the clusters Elymus-Anthriscus (14 s/b)and Elymus-Cirsium (16 s/b),both found predominantly in cereal production regions in southern Finland. Our results suggest that the biodiversity value of boundaries is lowest in the most intensive cereal production areas and highest in areas of mixed farming

    Impact of consumers' diet choices on greenhouse gas emissions

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    This study explores the impacts on agricultural and total GHG emissions of Finnish consumption if the share of animal based food products was reduced and if the share of ecologically produced food was to increase in Finland. GHG emissions associated with production of basic food items were quantified (per capita per annum) for current food consumption, for national standard diet recommendations, for a diet with no milk and beef and for a vegan diet including an oat-based milk susbstitute. The major source of GHG in primary food production is the cultivated soil. For the present average food consumption the emissions from the soil comprise 62 %, the share of emissions due to enteric fermentation is 24 %, whereas energy consumption and fertilizer manufacture both contribute about 8 %. Because of the extensive production mode, regarding GHG emissions the environmental performance, of organic production is poor
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