Efficient superfluorescent light sources with broad bandwidth

We demonstrate various efficient broad-band light sources at ~1µm wavelength with a 3dB bandwidth of up to 65nm at 108mW output power, based on rare-earth doped silica fibers and a simple adjustable spectral filter

Litteracitet, små barn och ipad : en fallstudie av ett barnbiblioteks användande av ny teknik i en läsfrämjande kontext

Detta paper utgår från, och är en kortare bearbetning av, vår masteruppsats med samma namn, skriven våren 2013 inom ämnet biblioteks- och informationsvetenskap vid Lunds Universitet, masterprogrammet i ABM. Uppsatsen i sin helhet återfinns på http://www.lu.se/lup/publication/3809044

Salt transfer under irrigation with treated wastewater in semi-arid Tunisia

A continuously growing population in the world has resulted in more agricultural activity in arid- and semi-arid areas where it once was harder to cultivate crops. Due to the high evaporation and the lack of rainfall in these areas it is necessary to irrigate the fields. In some areas it has become more and more common to use treated wastewater as an alternative irrigation source. When the soil is irrigated with saline treated wastewater, some of the salt will be concentrated in the soil. Excessive soil salinity can e.g. limit the plant water uptake, thus decreases the crop production, and it could lead to sever soil degradation. However, it is possible to use moderately saline water for irrigation without a significant risk for severe soil salinization if certain rules for water and soil management are established, implemented and followed. Therefore the main objective of this thesis is to do an assessment of the soil salinity in agricultural soil as a result of irrigation with treated wastewater. This master thesis will also try to estimate the effects on the soil salinity after a major rainfall event. This will be done with a field study that was conducted outside the city of Nabeul in the north-east of semi-arid Tunisia during 2 months. The soil salinity assessment done in this thesis can only be considered a qualitative one and the result can only be seen as an indication of an increase or decrease in the soil salinity over this particular field. However, the indications can be a help when deciding the objectives and limitations on future studies in this area. It has been concluded that a general increase in the soil salinity after two irrigation events cannot be seen. However, it was concluded that a small decrease in soil salinity could be seen already after 57.5 mm of rain. This indicating that the Tunisian winter rains can leach the soil from the salts added during irrigation, and that there is no significant risk of soil salinization in this field

An Evaluation of the Impacts of Bolsa Família on Schooling

Conditional cash transfer programs have been proven effective when aiming to decrease poverty and increase school enrollment among poor. The Brazilian conditional cash transfer program Bolsa Família is the largest program in the developing world and affect 13 million families in their everyday life. One of the long-term aims of Bolsa Família is to increase school enrollment in Brazil, which also is the focus of this thesis. With human capital theory as the foundation and with data from the Brazilian household survey PNAD2011, a regression discontinuity design is carried out in order to evaluate the impacts of Bolsa Família on school enrollment. As a complement to this analysis, semi-structured interviews with ten beneficiaries are conducted. The main result from the evaluation is that Bolsa Família does not increase school enrollment but appear to provide help for the children in poor and extremely poor families to assimilate education

The Economics of European Eel Management

The European eel stock is endangered. The European Union has, therefore, introduced strict policies to try to reverse the eel’s decline and reduce the threats to its survival. However, the European Union’s eel management policy has been implemented on a ‘one-size-fits-all’ basis, where all the affected countries have been given nearly identical targets, regardless of either the individual country’s costs for reducing damages to eels or its importance for the overall eel stock. In this paper, we draw on data from the different national eel management plans as well as from independent studies to compare the cost of measures to reduce eel mortality imposed in different countries. We compare the overall costs to those that could have been incurred with a union-wide, rather than fragmented, abatement program, and find that such a comprehensive management program would have been substantially cheaper and would have affected poorer member countries less

Lifetime quenching in Yb doped fibres

We have discovered that in ytterbium-doped silica fibres the excited state lifetime of a fraction of the Yb ions can be quenched to a very small value, leading to a strong unbleachable loss. This unexpected behaviour seems to be caused by some, yet unidentified, impurity or structural defect. It is of considerable relevance for various Yb doped lasers and-amplifiers including Er:Yb codoped fibres as used in telecommunication amplifiers although it should also be emphasized that fibres can be produced that are free from the quenching effect

Raman amplification and pulsed lasing in cladding-pumped germanosilicate fiber

We report for the first time Raman amplification in a cladding-pumped fiber. The double-clad germanosilicate fiber was pumped by a Q-switched Er-Yb co-doped fiber laser at 1570 nm. The power conversion efficiency was up to 36%, with a slope of 64%

Svenskproducerat proteinfoder till slaktsvin

Soybean meal from South America is the most common protein feed used for animal production in Sweden. Production of soybean has negative effects on the environment and the transports from South America to Sweden causes considerable CO2 emissions. Therefore it is a growing interest in locally produced protein feed in Sweden. Protein feeds that are possible to grow in Sweden are rapeseed, peas, faba beans and lupins. Those are adapted to the Nordic climate and are perfect to grow in cereal rotations. However, these protein feeds contain antinational substances (ANS) that cause problems like growth depression for growing- and finishing pigs, and therefore limit their use as animal feed. The most common ANS in those crops are glucosinolates, tannins, proteasinhibitors, alkaloids, lectins, saponins, vicin and convicin. Other protein rich feed that can be used in pig production is meal or pellets of lucerne, a common forage crop in Sweden, and byproducts from ethanol production like stillage or dried distillers’ grains with soluble. The problem with stillage is that the farm has to be located close to the factory due to expensive transports. It is possible to produce feed that meets the nutrient requirements of growing and finishing pigs from locally produced feedstuffs. But the feed will be more expensive than feeds including soybean, therefore the pork price has to be higher from pig grown on Swedish produced feed

Bark och armeringsmatta för att förebygga trampskador på betesytor hårt belastade av mjölkkor

Ett vanligt problem på mjölkgårdar är att drivningsgator, grindhål, ytor kring vattentråg och andra högt belastade ytor blir söndertrampade under betessäsongen. Detta kan bidra till problem som sänkt djurhälsa, försämrad mjölkkvalité och dåligt fungerande kotrafik. De söndertrampade ytorna är även känsligare för jorderosion och näringsläckage. För att undvika denna typ av problem kan markstabiliserande material anläggas på dessa ytor. Detta examensarbete är en del av projektet Kamp mot tramp, ett projekt finansierat av Stiftelsen Lantbruksforskning. Projektet skall utvärdera anläggning, kostnad och funktion av två markstabiliserande material, bark och armeringsmatta, under två säsonger. Syftet med detta examensarbete var att utvärdera resultatet under första betessäsongen. Bark och armeringsmattor anlades på ytor av ca 6 x 6 m i grindhål till betesfållor för mjölkkor, varje behandling upprepades i tre olika betesfållor. Barken anlades i ett 25-30 cm djupt lager på geotextil. Armeringsmattan anlades på marken med en geotextil limmad på undersidan av mattan och ett lager kalkgrus på ytan. Som kontroll användes ytor där ingen markstabiliserande åtgärd utförts. Försöksytorna utvärderades med ett gropindex och en visuell utvärdering utifrån fotodokumentation. Ett lägre gropindex innebar en lägre förekomst av gropar på ytan. Dokumentationen utfördes före mjölkkorna kom ut på bete på våren, tre gånger under pågående betessäsong samt en gång efter betessäsongens slut. Antalet gånger en ko passerade över varje yta registrerades under hela säsongen och vid slutet av betessäsongen varierade antalet passager i olika fållor mellan ca 2000-7000. Vid den statistiska analysen kunde man dock inte finna något statistiskt samband mellan antalet passager och antalet gropar, mätt som gropindex. Resultatet visade att ytorna med armeringsmatta hade ett signifikant lägre gropindex än både bark och kontroll samt att ytorna med bark hade ett signifikant högre gropindex än kontrolledet. Den visuella bedömningen bekräftade att ytorna med armering hade minst påverkan av tramp under betessäsongen. Skillnaderna mellan de tre försöksytorna i kontrolledet och två av försöksytorna med bark i fråga om trampskador var relativt små, dock uppvisade den tredje barkytan tydliga trampskador. Att trampskadorna generellt var små och skillnaderna inte var stora kan troligtvis kopplas till att det var en sommar med mycket lite nederbörd. Slutsatsen som kan dras är att armeringsmattan gav ett bättre skydd mot trampskador då försöksytorna med detta material var i stort sett opåverkade av kornas tramp och underhållet som krävs inför kommande säsong var minimalt. Under de torra förhållanden som rådde denna betessäsong tycktes även kontrollytorna klara sig relativt bra. Två ytor med bark uppvisade också bra resultat, dock krävdes ett större underhåll inför kommande säsong eftersom delar av eller hela barklagret måste bytas ut. Den tredje ytan med bark fick tydliga trampskador, men eftersom denna yta också blev utsatt för avsevärt större belastning än alla övriga ytor är det svårt att dra några långtgående slutsatser om bark som material efter bara ett försöksår. Ekonomiska kalkyler visar att armering är betydligt dyrare att anlägga, dock har barken ett dyrare underhåll. Detta gör att armeringen efter sju säsonger totalt sett är en lägre investering. Några studier av armeringsmattornas hållbarhet har ej återfunnits i litteraturen och det är därför svårt att veta om de har en hållbarhet som överstiger sju säsonger.A common problem on dairy farms during the grazing period is that surfaces in pasture walkways, entrances to paddocks and around the water troughs become trampled and muddy. Problems associated with these damaged surfaces are for example lowered animal heath, problems with milk quality and non-functioning cow traffic. Ground stabilizing materials can be used to avoid problems like these as they stabilize the surface and protect the ground from damage. This thesis is a part of a project with the aim to evaluate and compare the function and cost of two ground stabilizing materials, bark chips and grass carpet, with each other and a control treatment. The aim of this thesis is to evaluate the results from the first season after establishment. The three treatments were applied on area of a 6 x 6 m at the entrance to grazed paddocks used by dairy cows. The field study was performed in a randomized block design which included three blocks with each of the three treatments, giving a total of nine surfaces in the study. The control treatment consisted of paddock entrance surfaces that had not been subjected to any stabilizing measures. The bark chips were placed in a 25-30 cm deep layer on a sheet of geotextile. The grass carpet had a geotextile glued to the plastic mesh, it was placed on the ground and fixated with a layer of crushed limestone. The surfaces were evaluated with an index calculated from the number and size of holes in the surface, a lower index was an indication of less damage due to trampling. Visual evaluation was also performed using photos. The documentation was performed before the grazing season started, three times during grazing season and after the grazing season ended. The number of cow passages through the entrances was documented and over the entire season the number varied between approximately 2000-7000 cow passages in different paddocks. No significant effect of the number of cow passages on the surface index was seen in the statistical analysis. The results showed that the grass carpet had a significantly lower index than both the control and the bark chip surfaces. The surfaces with the bark chips on the other hand had a significantly higher index than the control. The visual evaluation confirmed that the grass carpet had the least damages caused by trampling. There was no great difference between the control and two of the bark chip surfaces while the third paddock entrance with bark chips showed clear signs of damage by trampling, However, this was also a paddock that had more passages by animals than any other paddock and it is therefore difficult to draw any definite conclusions after only one grazing season. In total the damage caused by trampling during this grazing season was very small, which was probably due to the very dry season. The conclusions from this study is that the grass carpet showed the greatest resistance to trampling damages as they almost were not affected at all by the gazing season. Compared with the grass carpet, more maintenance will be needed for the surfaces with bark chips before the next season, as most of the bark chips will have to be replaced. Cost calculations showed that the grass carpet is a lot more expensive to invest in, but as the maintenance cost is low, the total cost of the grass carpet will be lower than the bark chip if the grass carpet can be maintained for longer than seven seasons

An estimation of environmental impacts of dairy farming

The production of dairy products has both negative and positive external effects on the environment. Positive and negative external effects can be monetized and defined as environmental benefits and costs. Balancing environmental costs and benefits is crucial to prevent market failures. The aim of this paper was to investigate the balance between the environmental benefits and the environmental costs associated with dairy production in Sweden using cost-benefit analysis (CBA). Five dairy farms were used as case studies to conduct the analysis. Both an economic and a financial CBA was conducted for each farm. The results of the CBAs show that there are generally higher environmental costs than benefits. Three out of five farms have positive net present values in the economic CBAs, implying that these farms should go on with their production. The primary objective of the paper was to investigate whether or not there were differences in the results when analysing organic and conventional production systems and across different farm sizes. It is not possible to claim there are differences between conventional and organic production from the results in this CBA.Framställningen av mjölk och mjölkprodukter har både positiva och negativa effekter på miljön. Dessa positiva och negativa externaliteter kan värderas i monetära termer och definieras som miljönyttor och miljökostnader. För att undvika marknadsmisslyckande är det önskvärt att sträva efter balans mellan miljönyttor och miljökostnader. Syftet med denna studie var att utreda balansen mellan miljönyttor och miljökostnader som associeras med mjölkproduktion i Sverige genom att använda kostnads-nyttoanalys. Både en samhällsekonomisk och en finansiell kostnads-nyttoanalys utfördes. Resultaten i studien visar att miljökostnaderna är högre än miljönyttorna generellt sett. Tre av fem gårdar i studien har positiva nettonuvärden vilket antyder att dessa bör fortsätta med produktionen. Ett av målen med studien var att undersöka hur produktionssätt (ekologisk eller konventionell) och storlek på gården påverkade resultatet. Ingen skillnad mellan konventionell och ekologisk produktion kunde fastställas utifrån resultaten från kostnads-nyttoanalysen