Soil degradation has developed into a global problem that threatens food security of millions of people by annually causing serious damage and lowering productivity of hundreds of millions of hectares of arable land. Soil conservation measures that are aimed at abating or preventing various types of soil degradation can thus hold one of the keys to solving the worsening global food crisis. This pa

This paper is an empirical study on social work in China from the gender perspective. In this paper, I will analyze how social work in China, as a relatively new career, is being interpreted and constructed under Chinese modern gender norms; at the same time, how male social workers experience work and personal life in the context of feminized social work. There is an interesting phenomenon that

As the numbers of multinational corporations (MNCs) steadily increases production becomes more and more global. Today, production can easily be moved from one corner of the world to another if corporations find this to increase their profit. This puts trade unions in front of a new challenge as they now have to find strategies in order to promote and secure labour rights on a globalized labour mar

This thesis investigates the theoretical determinants of the credit default swap spread by employing a regime-shifting approach. The variables that are examined are leverage, stock return, volatility and interest rate. A sample of 47 companies was selected with daily mid-market quotes between Jan 2008-Dec 2010 in order to proxy the CDS spread. The research was conducted with the use of a linear re

The purpose of the thesis is to measure the effect of consistent and conflicting sponsorship scenarios on brand loyalty of sponsoring firms among club supporters. The method of research is a quantitative quota sample survey study on 715 Swedish respondents. Through a deductive approach the thesis tests hypotheses. The theoretical underpinnings of this thesis are derived from Customer based brand e

When a new linear accelerator is installed at a department it is of great importance that it is carefully controlled and calibrated before being put into clinical use. This is done with the acceptance test (AT). The mechanical parameters, the beam performance and the reproducibility of the dose output are tested. For each test there is a requirement which must be fulfilled for the machine to pass

210Pb dateringsstudie på 3000-4000 meters djup gjord på sediment från Marokanska och Arabiska havet för att undersöka om djuphavssediment är en stabil miljö. Tanken med examensarbetet är att undersöka konsekvenserna för dumpning av radioaktivt avfall i havet. Vilka regler gäller och vilka problem kan uppstå. Är det säkert eller ej? Vilka dumpplatser finns det och vad har man dumpat där? Ett av målThe earth surface consists of 71% of water and 29% land. 97% of that water is contained in saline seas. More than 90 per cent of the worlds living biomass can be found in the oceans. The sea has always been a possible dumpingsite for waste produced by man. Radioactive waste is the one of the most dangerous waste of all. Since the beginning of nuclear power research dumpsites around the world has b

Den här uppsatsen handlar om installationen och kalibreringen av en halvledardetektor i en underjordisk anläggning. Avsikten men att placera sin detektor långt ner under markytan är att minimera inflytandet av den kosmiska bakgrundsstrålningen. I kalibrerings förfarandet konstruerade vi en datormodel av detektorn. Med denna datormodel kan man simulera effektivitetskalibreringen av olika strålkällaThe aim of this thesis work has been to set up an ultra low-level gamma-ray spectrometry system in the underground laboratory HADES and applying the system to measurements of activation products in tantalum discs in order to determine low neutron fluxes. The main part of the work has been the efficiency calibration of the detector and the implementation of a computermodel for Monte Carlo simulatio

"The technology for planning and delivering radiotherapy has in the last decade undergone some revolutionary development and it is now possible to perform complex treatments such as stereotactic treatments and treatments using dynamic wedges, multileaf collimator and intensity modulation. The more precise limits surrounding the PTV have made it of utmost interest to be able to verify calculat

In this study we evaluate the clinical image quality of a computed radiography system for different tube voltages. Images of anthropomorphic phantoms were produced and the quality of the images was evaluated using visual grading analysis (VGA) by a group of experienced radiologists. Two different X-ray examinations were investigated: chest PA and pelvis AP. The exposure conditions were set so that

Mat som kontaminerats av radionuklider genom till exempel radioaktivt nedfall kan ge höga stråldoser till kroppen. Nuklider med långa halveringstider kan ackumuleras i kroppen och ge en hög tidsintegrerad absorberad dos. Personer med kronisk njursvikt kan erhålla höga stråldoser efter intag av radionuklider eftersom många radionuklider utsöndras via njurarna. I den här undersökningen har vi studerHigh internal radiation doses can result from food, contaminated by radionuclides from for example nuclear fallout. Nuclides with long half-lifes can accumulate in the body and give a high time-integrated absorbed dose. Persons with end-stage renal disease can receive high absorbed doses after intake of radionuclides, since many radionuclides are mainly excreted by the kidneys. In this study the d

The atmospheric nuclear bomb test “Castle Bravo”, which detonated at the Bikini Atoll in the Marshall Islands in 1954, led to the contamination of some populated atolls. Sediment samples from one such, the Rongelap Atoll, have been examined for plutonium (239, 240, 241, 242Pu) and americium (241Am) at Lawrence Livermore National Laboratory in Californina. Plutonium was measured with Accelerator Ma

The evaluation of clinical radiographs with the European Image Criteria method has in previous work proven to be an easy and straightforward method. The main drawback with this method is the large inter-observer variation. It has been proposed that the reason for this is that the observers get “distracted” by the surrounding structures in the image and that a sort of “first impression” of the imag

Phosphorus magnetic resonance spectroscopy (31P NMR) is a non-invasive technique for determining concentrations of intracellular metabolites linked to energy metabolism of human tissues. Inorganic phosphate (Pi) and adenosine triphosphate (ATP) are found in most tis-sues, while tissue specific metabolites such as creatine phosphate (PCr) and metabolites linked to lipid metabolism can be observed i

Motivationen med studien var den alldeles för höga stråldosen som används vid CTundersökningar. I de allra flesta fallen anpassas man inte rörströmmen efter patientens storlek och därmed får smalare patienter en onödigt hög stråldos. Målet var att reducera stråldosen till patienter som undersöks med datortomografi utan att minska på bildkvalité, genom att anpassa rörströmmen efter patientens stoIn this study we have investigated the possibilities of dose reduction in CT at a constant level of image quality by adjustment of the tube current to the phantom size. The motivation with the study is the high radiation doses to the patients and the increasing frequency of CT examinations and the variety of examinations in CT, and that the same tube current is used for different patient sizes. Ac

Funktionell magnetresonanstomografi (fMRI) är en teknik som gör det möjligt att kartlägga aktivering inom olika delar av hjärnan. Genom att samla in bilddata då patienten är i vila, och sedan jämföra dessa med data insamlade medan patienten är aktiv (t.ex. utför fingerrörelser), kan en bild skapas som visar var i hjärnan aktivering har skett. Dessa bilder kan t.ex. användas för att bedöma om det äFunctional MRI (fMRI) is a technique for determining which parts of the brain are activated when a subject experiences some type of physical sensation or performs an activity. This technique has during the past several years become a very useful tool for understanding functions of the nervous system, and the development of clinical applications is rapidly progressing. However, fMRI is not straight

Effects of flow are a fundamental part of magnetic resonance imaging (MRI). Since almost every part of the body contains some kind of flow, the effects are seen in generally all MR images. The presence of flow in an image slice may be a vast source of artefacts but the effects of flow can also be used for diagnostic purposes, for example in magnetic resonance angiography (MRA). In MRA, flow effect

Diffusionsviktad magnetiskresonanstomografi (MRT) är en metod där vi med hjälp av magnetfält kan märka in vattenmolekyler och följa de slumpmässiga rörelser som alla molekyler uppvisar. Den slumpmässiga rörelsen uppstår p.g.a. termisk energi (värmeenergi) och varierar med temperaturen och ämnet som omger molekylerna. Tensoranalys är ett matematiskt verktyg för att skapa modeller för hur den omgivaDiffusion weighted magnetic resonance imaging (MRI) is a modality that offers the possibility to measure molecular motion such as water self-diffusion which is in the order of 10-9 m2/s. The basic formalism has been known since the middle of the 20:th century, it is however, only during the last decade that it has been used for imaging. Through tensor analysis of diffusion weighted images, acquire

Up to recently mobile gamma spectrometry has mostly been performed with NaI(Tl)-based detector systems. However lately the interest of using HPGe(High Purity Germanium)-based systems have increased and one has realised that the excellent energy resolution of HPGe-detectors, in combination with the possibility to manufacture larger crystals than before, is an advantage not only when performing in s

A patient positioning system for Boron Neutron Capture Therapy (BNCT) for treatment of brain tumours was designed, and its accuracy was evaluated. The system will be used at the BNCT facility under construction at Studsvik, Sweden. Recent studies have shown that the accuracy in the patient positioning procedure in BNCT is of more significance than generally perceived in the past. Therefore one obj