192 research outputs found

    The Isolated Peasant. Long-term Growth in Demand and Spatial Patterns of Agricultural Supply in Southern Sweden, 1702-1857

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    Previous research has found clear spatial patterns of agricultural supply, both in pre-industrial Europe (Grantham 1978; Grantham 1989; Kopsidis 2009) and in the less developed countries of today (Benziger 1996; Stifel & Minten 2008). The spatial structure of farming intensity is mainly attributed to the declining net-returns with the distance from the market. This paper examines the impact of distance on agricultural productivity and whether the long-term growth in demand had a diminishing impact on the spatial variation in farming intensity. The analysis is carried out by using a database on estimates of agricultural production on the micro-level together with additional information on distance from a map from the 19th century for about 2200 farm households in the province of Scania in southern Sweden during the period 1702-1857. The effect of distance on agricultural production is studied with a general least square regression (GLS) for the time periods 1702-1775, 1776-1825 and 1826-1857. The results demonstrate a distinct spatial variation in farming intensity in southern Sweden. Further, the findings also show that the spatial patterns of agricultural supply even increased over time, despite a considerable growth in demand. Overall, the results indicate that increasing demand in itself was not a sufficient pre-condition for reducing the spatial variation in farming intensity

    Hybrid Microwave-Cavity Heat Engine

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    We propose and analyze the use of hybrid microwave cavities as quantum heat engines. A possible realization consists of two macroscopically separated quantum dot conductors coupled capacitively to the fundamental mode of a microwave cavity. We demonstrate that an electrical current can be induced in one conductor through cavity-mediated processes by heating up the other conductor. The heat engine can reach Carnot efficiency with optimal conversion of heat to work. When the system delivers the maximum power, the efficiency can be a large fraction of the Carnot efficiency. The heat engine functions even with moderate electronic relaxation and dephasing in the quantum dots. We provide detailed estimates for the electrical current and output power using realistic parameters.Comment: 5 pages, 3 figures, final version as published in Phys. Rev. Let

    Kom nÀrmre!

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    Det finns mĂ€ngder av olika typer av studier som visar pĂ„ de positiva effekterna som vistelsen i naturen har pĂ„ vĂ„rt vĂ€lmĂ„ende. Det hjĂ€lper oss bĂ„de psykiskt och fysiskt genom att till exempel ge oss Ă„terhĂ€mtning, en minskad kĂ€nsla av stress och miljöer för fysisk aktivitet. Trots detta minskar kontakten mellan mĂ€nniska och natur som en konsekvens av en rad faktorer. För vissa kan naturen kĂ€nnas obehaglig i och med en ovana och brist pĂ„ kunskap. Andra kan ha svĂ„rt att ta sig ut till naturomrĂ„den rent fysiskt, pĂ„ grund av till exempel rörelsemĂ€ssiga funktionsnedsĂ€ttningar. Med tanke pĂ„ den stora tillgĂ„ngen pĂ„ fina naturomrĂ„den vi har i Sverige gĂ„r mĂ„nga miste om alla de möjliga fördelarna som de skulle kunna fĂ„ om de lyckades ta sig ut i naturen mer. Dessutom har en ökad naturvistelse och naturkontakt pĂ„ lĂ€ngre sikt en positiv inverkan pĂ„ mĂ€nniskors miljömedvetenhet och naturomsorg, nĂ„got som har betydelse för den hĂ„llbarhetsomstĂ€llning vi stĂ„r inför. Det hĂ€r examensarbetet syftar till att undersöka hur olika typer av landskapstillĂ€gg kan bidra till att locka ut fler till naturomrĂ„den och dĂ€rmed bidra till en ökad naturkontakt och en frĂ€mjad folkhĂ€lsa. Det har undersökts genom studerandet av olika typer av litteratur, samtal med olika personer med en yrkesmĂ€ssig eller ideell koppling till Ă€mnet och genom studerandet av ett par olika referensprojekt. Resultatet av detta har sammanstĂ€llts i arbetets Kunskapsbas och kan kort sammanfattas med fem punkter: utveckling av entrĂ©omrĂ„den, tillgĂ€ngliggörande, en ökad orienterbarhet, fler bekvĂ€mligheter och skapandet av mĂ„lpunkter genom ökade möjligheter till aktiviteter. Ett mer konkretiserat förslag pĂ„ hur dessa tillĂ€gg kan omsĂ€ttas pĂ„ en faktiskt plats presenteras senare i arbetet. Det platsspecifika förslaget utgĂ„r frĂ„n en del av OrlĂ„ngens naturreservat i Huddinge kommun och inkluderar en platsanalys och en utvecklingsplan med förslag pĂ„ Ă„tgĂ€rder. Det finns ett antal Ă„tgĂ€rder som skulle kunna appliceras pĂ„ det valda studieomrĂ„det kopplat till de fem sammanfattande punkterna. För att nĂ€mna nĂ„gra exempel gĂ€ller det dels utveckling av omrĂ„dets entrĂ©punkt och en förbĂ€ttring av befintliga parkeringsplatser. Dels handlar det om en utveckling av befintligt skyltsystem med tydligare vĂ€ganvisningar och fler informationsskyltar. Ett fĂ„geltorn och upprĂ€ttandet av en ny upplevelsestig skulle Ă€ven kunna vara sĂ€tt att locka fler till platsen och nĂ€rmare naturen. I diskussionen tas olika aspekter upp med koppling till utveckling av naturomrĂ„den och mĂ„let att nĂ„ fler besökare. Även om landskapstillĂ€gg kan ha en betydande roll för att locka ut fler i naturen sĂ„ kan det istĂ€llet i mĂ„nga fall vara avgörande med anordnandet av faktiska aktiviteter för att ovana grupper faktiskt ska ta sig ut och kĂ€nna sig bekvĂ€ma med det. En utveckling av omrĂ„det som mĂ„lpunkt Ă€r ocksĂ„ beroende av en viss nivĂ„ av kommunikation för att kunna nĂ„ ut till en bred skara. NĂ€mnas bör Ă€ven betydelsen av personliga preferenser nĂ€r det kommer till upplevelsen av naturomrĂ„den. Olika Ă„tgĂ€rder gynnar olika grupper av mĂ€nniskor, dĂ€r vissa föredrar de miljöerna som Ă€r mindre tillrĂ€ttalagda. För att nĂ„ de som annars inte tar sig ut, kan olika typer av landskapstillĂ€gg dock vara av större betydelse.There is plenty of scientific evidence on the positive health benefits of spending time outside in nature. It helps to improve both our mental and physical health through for instance restoration, stress reduction and environments for physical activities. Yet, the contact between human and nature is reducing as a consequence of various factors. Some people might feel a sense of discomfort being in nature due to a lack of knowledge and unfamiliarity with more natural settings. Considering the large and many nature areas we have in Sweden, many people miss out on all the possible positive wellbeing benefits they could get if they would use it more. In addition, an increased time spent in nature could have a positive impact on people’s care for nature, and environmentally responsible behaviour, which is of great importance in the transition towards a more sustainable society. The aim of this paper is to get an understanding of how different types of additions in the landscape can contribute to more people getting out in nature, and thereby increase people’s both wellbeing and contact with nature. The study is based on different types of literature, interviews with people with a professional connection to the subject, and through observations of different existing examples. The result of this can be summarised in five categories: development of entrances, improved accessibility, increased orientability, more amenities and creation of destination points through increased possibilities for activities. A more concrete proposal of how these kinds of additions can be implemented is presented in the case study chapter. The case study is based on a part of OrlĂ„ngen’s nature reserve in Huddinge municipality and involves a site analysis and a plan of development with more specific suggestions of development. Several measures can be implemented on the site based on the five categories. To mention some examples, these include an improvement of the area’s entry points with adjacent parking spaces. It also includes a development of the existing sign system with better directional and informational signs. A bird tower or a new experience path are also suggested to attract more people and increase their contact with nature. Even if landscape additions can play a significant role to attract more people to visit nature, it can in many cases instead be more important with arrangements of actual events and activities to address the groups that are least familiar with nature. A development of the area as a stronger destination point is also dependent on some kind of communication to reach out to a broader public. Worth mentioning is also the significance of personal preferences when it comes to the experience of nature. Different measures favour different groups of people, and some might prefer the more naturalistic environments without additions. However, landscape additions can be of greater value to address the ones that visit nature areas more seldom

    Plant selection for rain gardens : a design for a rain garden in Rosendal, Uppsala

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    En av de funktioner grönytor fyller Àr att ta hand om och infiltrera vatten. NÀr stÀder i vÀrlden vÀxer, ökar mÀngden hÄrdgjorda ytor. Det innebÀr att avrinningen blir större och dÀrmed Àven mÀngden dagvatten som behöver tas omhand. PÄ grund av klimatförÀndringarna förvÀntas dessutom nederbörden stundtals bli mer intensiv. RegnbÀddar har tagits fram som en metod för att hantera vattenflöden och minska belastningen pÄ stÀders dagvattenledningssystem. Genom att anlÀgga nedsÀnkta vÀxtbÀddar i anslutning till hÄrdgjorda ytor kan dagvatten ledas in till bÀdden dÀr det kan fördröjas och sedan antingen infiltrera ner i marken eller ledas vidare. Med tanke pÄ bÀddarnas goda infiltrerande förmÄga skapas sÀrskilda vÀxtförutsÀttningar. VÀxterna ska klara lÀngre perioder av torka samtidigt som att vattnet i bÀdden stundtals kan komma att bli stÄende. I denna rapport presenteras listor med vÀxter som kan lÀmpa sig för gestaltning av regnbÀddar i Uppsalatrakten. För att visa pÄ hur vÀxtlistorna kan tillÀmpas presenteras ocksÄ en gestaltning för en regnbÀdd i Rosendal, Uppsala. Gestaltningen utgick bland annat frÄn att den skulle vara praktfull med en variation av arter, ha Ärstidsvariationer sÄsom vinterstÄndare och att den skulle ta hÀnsyn till omgivningen. Detta genom att verka avskiljande mellan gata och trottoar samtidigt som att sikten mellan trafikanter inte ska hindras alltför mycket. Det finns mÄnga faktorer som pÄverkar regnbÀdden sÄsom stÄndort, vilken varierar mycket frÄn plats till plats. DÀrför finns ingen garanti pÄ att vÀxterna kommer att fungera bra i bÀdden. Förslaget behöver testas i praktiken för att faktiskt se om det Àr lÀmpligt.Green infrastructure contributes to many ecosystem services. One of them is to take care of, and infiltrate water. When cities are growing, the amount of impermeable surfaces increase. That leads to an increasing amount of surface water that needs to be taken care of. In addition, rainfalls are expected to get more intense as a consequence of climate change. Rain gardens have been developed as a method to cope with these higher run-offs. Through depressed rain gardens next to impermeable surfaces, runoff can be led directly to the installation where it can be delayed and subsequently either infiltrate through the ground or be led onwards. The high infiltration capacity of the rain gardens makes the growth environment very special. The plants are required to cope with long periods of drought meanwhile the water in the plantation during shorter periods can be standing. It can therefore be a challenge to find plants who can manage these conditions. This report presents lists of plants that can be suitable for designing rain gardens in the region of Uppsala. A planting design is also presented on a rain garden in Rosendal, Uppsala, to exemplify how the lists can be applied in reality. Principles for the design was for example to make the plantation grand with various species, a seasonal variation and with considerations the surroundings. Since there are many factors that affect the environment in the rain garden, the planting design has to be implemented and tested practically to see how it works in reality

    Pump-probe scheme for electron-photon dynamics in hybrid conductor-cavity systems

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    Recent experiments on nanoscale conductors coupled to microwave cavities put in prospect transport investigations of electron-photon interplay in the deep quantum regime. Here we propose a pump-probe scheme to investigate the transient dynamics of individual electron-photon excitations in a double quantum dot-cavity system. Excitations pumped into the system decay via charge tunneling at the double dot, probed in real time. We investigate theoretically the short-time charge transfer statistics at the dot, for periodic pumping, and show that this gives access to vacuum Rabi oscillations as well as excitation dynamics in the presence of double dot dephasing and relaxation.Comment: 5 Pages, 5 figure

    Microwave quantum optics and electron transport through a metallic dot strongly coupled to a transmission line cavity

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    We investigate theoretically the properties of the photon state and the electronic transport in a system consisting of a metallic quantum dot strongly coupled to a superconducting microwave transmission line cavity. Within the framework of circuit quantum electrodynamics we derive a Hamiltonian for arbitrary strong capacitive coupling between the dot and the cavity. The dynamics of the system is described by a quantum master equation, accounting for the electronic transport as well as the coherent, non-equilibrium properties of the photon state. The photon state is investigated, focusing on, for a single active mode, signatures of microwave polaron formation and the effects of a non-equilibrium photon distribution. For two active photon modes, intra mode conversion and polaron coherences are investigated. For the electronic transport, electrical current and noise through the dot and the influence of the photon state on the transport properties are at the focus. We identify clear transport signatures due to the non-equilibrium photon population, in particular the emergence of superpoissonian shot-noise at ultrastrong dot-cavity couplings.Comment: 19 pages, 10 figure
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