Three-wave mixing in Josephson travelling-wave parametric amplifiers

This work explores possibilities of building a wide-band, quantum-limited low-noise amplifier by means of three-wave mixing (3WM) in different kinds of Josephson travelling-wave parametric amplifiers (TWPAs). We extend the theory of the continuous three-mode model to include any number of up-converted modes in the small frequency limit where the frequency dispersion is close to linear. We also extend the theory to describe a discrete chain at frequencies close to the spectral cutoff where there is no up-conversion. In both cases we find that the gain is significantly reduced compared to the prediction by the continuous three-mode model. At the high frequencies we cannot pump strongly enough to overcome the increasingly strong dispersion, while in the small frequency limit, the dispersion can be overcome but the gain is then reduced by up-conversion processes. The developed theory is in quantitative agreement with experimental observations.To recover the high gain predicted by the continuous three-mode model, we propose to engineer a TWPA with dispersive features to create a two-band dispersion relation, either by adding resonant phase matching (RPM) features, or by periodically modulating the parameters of the chain. By placing the pump frequency within the upper band, close to the cutoff frequency, while placing the signal in the lower band, we prove that there exists a sweet spot where the signal and the pump are phase matched while the up-conversion is inhibited. We solve the discrete equations for the RPM-based TWPA and show that the gain is expected to grow exponentially with the length of the TWPA

Off-shell structure of twisted (2,0) theory

A $Q$-exact off-shell action is constructed for twisted abelian (2,0) theory on a Lorentzian six-manifold of the form $M_{1,5} = C\times M_4$, where $C$ is a flat two-manifold and $M_4$ is a general Euclidean four-manifold. The properties of this formulation, which is obtained by introducing two auxiliary fields, can be summarised by a commutative diagram where the Lagrangian and its stress-tensor arise from the $Q$-variation of two fermionic quantities $V$ and $\lambda^{\mu\nu}$. This completes and extends the analysis in [arXiv:1311.3300].Comment: 15 pages, 2 figure

Individualism på bekostnad av individen? - LSS, jämlikhet och frihet utifrån ett klassperspektiv

The bearing principles of the Law of support and Service for people with Certain Functional Impairments (LSS) are to create a freer and more self-determined user, limit government intrusion and paternalism. This whilst the main objectives of the Health Care Law are to uphold good health and care on equal terms for the entire population. This essay investigates whether these two principles might be contradictory in practice. I do so by analyzing the liberal and individualistic ideas and ideals in the LSS-law in relation to an interview material acquired through interviews with users, relatives and government administrators with connection to LSS. To interpret the results of my findings and to understand how the LSS-law´s liberal viewpoint affects users, I analyze the material from a Bourdieuen class perspective. My results indicate that there seem to be a lack of awareness regarding the internal differences amongst the LSS users which creates, aggregates and cements the initial socio-economic differences between people with disabilities. Hence, the liberalism of LSS may not actually promote freer and more self-determined user, but an unjust health care system, where the level of service and care are based on the individual user´s capacity to make claims and adjust to the regulations, regularities and procedures of the LSS

Kommunal revision och bolagsrevision - vad är skillnaden?

Syftet med uppsatsen är att jämföra vad som skiljer bolagsrevisionen från den kommunala. Vilka skillnader finns det mellan respektive regelverk, revisorernas uppgifter osv.

New laboratory lifetime measurements of U II for the uranium cosmochronometer

We present new measurements of radiative lifetimes for six energy levelsof singly ionized uranium, U II, using laser-induced fluorescencetechnique. One of the levels,5f36d7p6M13/2 at 26191 cm-1,decays by a transition at 3859.6 Å. This line has recently beenobserved in the spectrum of the metal-poor star CS1082-001, the firstdetection of uranium outside the solar system. The lambda 3859 line canbe used as the presently most accurate cosmochronometer (Cayrel et al.cite{Cayrel}). Our value of the lifetime of the6M13/2 level is 18.6+/-0.7 ns, and it confirms thef-value used in the Nature article by Cayrel et al. (cite{Cayrel}),which is based on an experimental lifetime of 20+/-5 ns (Chen &Borzileri cite{Chen}). The new measurement also removes the doubt aboutthe choice between that value and other f-values in the literature,differing by a factor of 3. Adopting the same branching fraction as Chen& Borzileri (cite{Chen}) for the 3859.6 Å line, we derive agf-value of 0.68, which is 8% higher than the value used by Cayrel etal. (cite{Cayrel}). Of significance for the chronometer is also thereduced uncertainty of the radiative lifetime, 4% compared to 25%, andconsequently of the f-value, which should decrease the uncertainty inthe determination of the stellar age considerably

The FERRUM project: improved experimental oscillator strengths in CrII

We report absolute oscillator strengths for 119 Cr II transitions in the wavelength region 2050-4850 angstrom. The transition probabilities have been derived by combining radiative lifetimes, measured with time- resolved laser induced fluorescence, and branching fractions from intensity calibrated Fouirer transform spectrometer data. New radiative lifetimes for the 3d(4)(D-5)4p F-4, D-4 and P-6 terms are reported, adding up to a total of 25 energy levels with measured lifetimes used to derive this improved set of atomic data

Economic value for the use of crossbreeding and sexed sperm for dairy and beef cattle

Könssorterad sperma är selekterad sperma. Vid användning av X-Vik fås kvigkalvar med en 90 % säkerhet och vid användning av Y-Vik kan man med 85 % säkerhet säga att en kalv kommer bli en tjur. Användning av XVik ger snabba avelsframsteg i besättningen genom att en förhöjning av mjölkkobesättningens medel NTM (Nordic total merit index) sker. NTM är ett gemensamt avelsindex för Sverige, Danmark och Finland. Indexet som används för att bedöma mjölkkor kallas mjölkindex och i det ingår mjölkmängd, fettmängd och proteinmängd. Användning av X-Vik kan även garantera att man har tillräckligt många rekryteringsdjur vilket i sin tur öppnar upp möjligheter att systematiskt använda Y-Vik av en köttrastjur och på så sätt få korsningstjurar av mjölk och köttras att föda upp till slakt. Effekten som kan fås av korsningsavel är en högre tillväxt än snittet av föräldradjurens tillväxt, friskare och livskraftigare djur samt en högre fertilitet. Nackdelar som finns med den könssorterade sperman är att den är dyrare. En dos av könssorterad sperma kostar för Y-Vik ca 116 kr mer än en konventionell dos från en mjölkrastjur. För X-Vik kan en dos kosta upp till 75 kr mer än en konventionell dos från en mjölkrastjur. En annan nackdel är den sämre fertiliteten som en könssorterad dos ger. En konventionell dos har en genomsnittlig fertilitet på 1,8 insemineringar/ko, medan en könssorterad dos ligger på 2,2 insemineringar/ko. För att få ut så mycket som möjligt från en korsning mellan mjölkras och köttras gäller det att tillfredsställa dess tillväxtbehov med såväl foder som dess inhysning. I de intervjuer som har gjorts med lantbrukare på två gårdar i Sverige var man positivt inställd till användandet av könssorterad sperma för att få kvigor. Däremot var man mera negativt inställd till könssorterad sperma för att få tjurar. I en ekonomisk kalkyl som gjorts i denna studie har 20 % av en besättning blivit inseminerade med Y-Vik köttras och 20 % av besättningen har blivit inseminerad med X-Vik. De övriga 60 % inseminerades på konventionellt vis. Kalkylerna gav en ökad lönsamhet/djur jämfört med en användning av 100 % konventionell inseminerad besättning.With the use of sexed sperm a beef or dairy producing farmer can with 90% accuracy receive a heifer-calf when using X-Vik doses (selected sperm to produce heifer-calves). If the farmer instead choses to use Y-Vik (selected sperm to produce bull-calves) doses he will get a bull-calf 85% of the times. The surplus when using X-Vik is that the dairy producer gains faster breeding progress by increasing the dairy herd’s average NTM (Nordic total merit index) value. NTM is a breeding index that the countries Sweden, Finland and Denmark have developed together and it’s therefore the same in the three countries. There are different indexes when breeding for different purposes. The dairy index is calculated for cows and bulls by yield of milk, yield of protein and yield of fat in the milk. The meat index is calculated for bulls by looking at the growth rate and the classification of carcass. The pedigree index is given to calves before their birth and is calculated from data for the parents. The use of X-Vik can open up for a more effective beef production in the dairy herd. X-Vik can be integrated with the use of Y-Vik at the same extent as X-Vik in the herd. By using X-Vik to the best dairy cows the farmer will get the replacement animals needed for the dairy herd and they will at the same time increases the herds milk index. That leaves openings to use YVik to produce crossbred bull-calves for beef production. The advantages of using crossbreeding with a beef breed are that the calves gain a higher growth rate and better confirmation class than purebred dairy calves. Crossbred calves also become more viable and more resistant to diseases. However, the crossbreeds have a lower fat class than purebred dairy calves. There are considerations of using sexed sperm. It is having a lower fertility than the conventional sperm. It is also more expensive and you can’t be 100% sure that the result will be a heifer-calf with the use of X-Vik or a bull-calf with the use of Y-Vik. One dose of Y-Vik sperm cost 116 SEK more than a conventional dose from a dairy bull. The X-Vik dose costs 75 SEK more than the conventional dose from a dairy bull. The fertility for a conventional dose is 1.8 inseminations/cow and the fertility of the sexed sperm dose is 2.2 inseminations/cow. The economic benefit of using selected sperm and rossbreeding is highly dependent on if the animal’s growth potential is used. The growth can be inhibited by many variables, such as bad housing, inadequate feeding and stress. In interviews conducted on two different farms in Sweden the farmers were positive to the use of X-Vik. However, they had a more negative attitude toward the Y-Vik sperm because they had the idea that Y-Vik had lower fertility than X-Vik. The economic calculation in this study was made in a dairy herd of 100 Holstein cows. 100% conventional inseminations in the herd were compared to, when 20% of the best dairy cows were inseminated with X-Vik and 20% of the genetically lowest dairy cows with Y-Vik sperm of the breed Limousine. The rest was inseminated with conventional sperm. The study resulted in an increase of the profit by 1 142 SEK/cow when the crossbreed calves were kept until they were 14 month and then sent to slaughter. The increase of the profit was 1 177 SEK/cow when the crossbred calves were sold after weaning, at the age of two months

Företag och demokratisering

Det internationella politiska systemet, med FN i spetsen, klargör med tydlighet att multinationella företag har att förhålla sig till suveräna staters nationella lagstiftning och sedvänja. Detta system skapar ett juridiskt och moraliskt vakuum för multinationella företag som verkar i länder där rättsstaten är svag, arbetsrätten dåligt utvecklad och grundläggande mänskliga rättigheter inte understödjs. Vi undersöker häri i vilken mån svenska företag med verksamhet i sådana länder har möjlighet att påverka utvecklingen mot demokrati och förbättrade sociala förhållanden. Vi analyserar även vilka problem den förhärskande liberala statscentrerade synen på staters suveränitet kan innebära för företags samhälleliga ansvarstagande. Analysen mynnar ut i en diskussion där vi konstaterar att den rådande synen inte tillräckligt lyckas förklara multinationella företags inflytande på samhällsutvecklingen och att den dessutom kan ha en passiviserande effekt på företags agerande