646 research outputs found
Children and Democracy. A Minor Field Study about Child-led Organisations in Urban Tanzania.
The thesis investigates whether child-led organisations in Tanzania contributes to the consolidation of democracy through conducting a case study of five child-led organisations in urban Tanzania
Analysis of Optical Flow Algorithms for Denoising
When a video sequence is recorded in low-light conditions, the image often become noisy. Standard methods for noise reduction have difficulties with motion. But the interesting parts in a video is often the ones that are moving, for instance a burglar captured in a surveillance video. One approach for denoising video sequences is to use temporal filtering controlled by optical flow, which describes how pixels move between two image frames. Today, there exists few studies comparing how different optical flow algorithms perform on noisy video sequences. Four different algorithms have been analyzed in the thesis. Moreover, a comparison on how well they can be used to improve the result of a temporal noise filter has been done. The conclusion of the comparison is that optical flow is useful for noise reduction. Algorithms based on patch matching and edge consistency perform better than algorithms based on color consistency. A recommendation for future work is to combine the best parts of each algorithm to develop a new optical flow algorithm, specialized on noisy image sequences. Furthermore, develop and implement a sophisticated optical flow based noise filter in camera hardware
Efficient Process-to-Node Mapping Algorithms for Stencil Computations
Good process-to-compute-node mappings can be decisive for well performing HPC
applications. A special, important class of process-to-node mapping problems is
the problem of mapping processes that communicate in a sparse stencil pattern
to Cartesian grids. By thoroughly exploiting the inherently present structure
in this type of problem, we devise three novel distributed algorithms that are
able to handle arbitrary stencil communication patterns effectively. We analyze
the expected performance of our algorithms based on an abstract model of inter-
and intra-node communication. An extensive experimental evaluation on several
HPC machines shows that our algorithms are up to two orders of magnitude faster
in running time than a (sequential) high-quality general graph mapping tool,
while obtaining similar results in communication performance. Furthermore, our
algorithms also achieve significantly better mapping quality compared to
previous state-of-the-art Cartesian grid mapping algorithms. This results in up
to a threefold performance improvement of an MPI_Neighbor_alltoall exchange
operation. Our new algorithms can be used to implement the MPI_Cart_create
functionality.Comment: 18 pages, 9 Figure
The monomial representations of the Clifford group
We show that the Clifford group - the normaliser of the Weyl-Heisenberg group
- can be represented by monomial phase-permutation matrices if and only if the
dimension is a square number. This simplifies expressions for SIC vectors, and
has other applications to SICs and to Mutually Unbiased Bases. Exact solutions
for SICs in dimension 16 are presented for the first time.Comment: Additional author and exact solutions to the SIC problem in dimension
16 adde
Sustainable Food System â Targeting Production Methods, Distribution or Food Basket Content?
Agriculture is the single most important contributor to the eutrophication of the Baltic Sea. Itis responsible for 59% of the anthropogenic nitrogen and 56% of the phosphorous emissions(HELCOM, 2005). A second important source of nutrient emissions is at the other end of thefood system â emissions from municipal waste-water treatment plants and from privatehouseholds. Addressing different aspects of the food system is thus crucial for the Baltic Seaenvironment. To tackle eutrophication both nitrogen and phosphorous loads should bereduced (MVB, 2005). This can be achieved if emissions from the food system are reduced,e.g. by closing the nutrient cycle from soil to crop and back to agricultural soil (Diaz andRosenberg, 2008). Granstedt (2000) finds that the high surplus and emissions of nitrate andphosphorous in Swedish agriculture is a consequence of specialized agriculture with itsseparation of crop and animal production. Similar findings are reported from different partsof Europe (Brower et al., 1995). About 80% of cropland in Sweden is used for fodderproduction but the animal production is concentrated to a limited number of specializedanimal farms. Manure, with its contents of nutrients from the whole agriculture area, istoday concentrated on only 20% of the Swedish arable land (Statistics Sweden, 2011). Thisresults in high nutrient surplus and load of nitrogen and phosphorus from these areas.Granstedt (2000) concludes that the emissions can be limited by combining best availableagricultural technology with increased recycling of nutrients within the agricultural systemtrough integration of crop and animal production - ecological recycling agriculture (ERA).This facilitates an efficient use of the plant nutrients in farm yard manure. Other studies ofnutrient balances comparing farming systems and lifecycle assessment report similarobservations (Halberg, 1999; Myrbeck, 1999; Steinshamn et al., 2004; Uusitalo, 2007). Thepotential of reduced nutrient emissions trough ERA was confirmed in case studies on localorganic farms around the Baltic Sea (Granstedt et al., 2008; Larsson and Granstedt, 2010).Carlsson-Kanyama (1999) found that greenhouse gas emissions could be reduced by localand organic food production due to shorter transportation. Similar results are reported in acompilation of studies (FiBL, 2006) and in studies of local production and processing inJĂ€rna, Sweden (Wallgren, 2008). According to Carlsson-Kanyama et al. (2004) the reductionsare not significant unless local distribution becomes more efficient.QC 20160524</p
Bridging immune activation with the kynurenine pathway : implications for psychosis
Kynurenic acid (KYNA), an endogenous N-Methyl-D-aspartic acid receptor (NMDAR) antagonist, is elevated in patients with schizophrenia. In addition, elevated levels of KYNA are associated with activation of the immune system, which also has been implicated in the development and maintenance of psychotic disorders, including schizophrenia.
The aim of this thesis was to further investigate the role of KYNA in the pathophysiology of schizophrenia. Thus, patients with schizophrenia were examined with respect to cerebrospinal fluid (CSF) levels of interleukin (IL)-6, kynurenines, and the functional effects of G protein- coupled receptor kinase 3 (GRK3) expression. Mice administered lipopolysaccharide (LPS), amphetamine, or lacking the immune-regulating enzyme GRK3, were studied with respect to biochemical and functional aberrations associated with schizophrenia.
The elevated CSF levels of IL-6 found in patients with schizophrenia were associated with increased CSF KYNA levels. Administration of IL-6 increased KYNA production in astrocytes and lower GRK3 expression in healthy individuals correlated to increased CSF KYNA levels. GRK3 was further found to be associated with psychosis in patients with bipolar disorder.
Subchronic elevation of KYNA, or lack of GRK3 augmented the amphetamine response as verified by increased locomotor activity and dopamine release. Signs of amplified immune activity were evident in Grk3-/- mice by increases in astrocyte markers, IL-1ÎČ, kynurenine, and KYNA turnover. Intracerebroventricular (ICV) administration of IL-1ÎČ, and dual, bot not single injections of LPS increased brain KYNA. In addition, mice injected ICV with IL-1ÎČ or lacking GRK3 showed disrupted prepulse inhibition (PPI).
Results presented here point to an intimate relationship between immune activation, the kynurenine pathway, and psychosis. Specifically, immune activation, present in patients with schizophrenia, was demonstrated to activate the kynurenine pathway. In addition, activation of the kynurenine pathway induced KYNA and lead to behavioral aberrations in rodents
Insiderinformation - analys och legalitetsaspekter
Legaldefinitionen av insiderinformation Äterfinns i 1 § 1 MmL. I den hÀr uppsatsen analyseras den del av legaldefinitionen som lyder: ''information om en icke offentliggjord eller inte allmÀnt kÀnd omstÀndighet som Àr Àgnad att pÄverka kursen''. HÀrvidlag fokuseras pÄ de olika tolkningssvÄrigheter som finns och den försvagning av legalitetsprincipen samt de svÄrigheter för Äklagare och domare som dÀrmed blir följden. Först och frÀmst uppstÄr svÄrigheter nÀr det gÀller att avgöra vad som kan utgöra en omstÀndighet, till vilken sannolikhet en omstÀndighet skall föreligga samt grÀnsdragningen mot ryktesspridning. I detta avseende analyseras de rÀttskÀllor som gör gÀllande att rykten samt köp- och sÀljrekommendationer inte kan utgöra insiderinformation. Slutsatsen i detta avseende Àr att Àven information om ett rykte och en köp- eller sÀljrekommendation skulle kunna utgöra insiderinformation. Vidare Àr formuleringen ''icke offentliggjord eller inte allmÀnt kÀnd'' problematisk. Lagtexten ger sken av att det rÀcker med att informationen Àr antingen icke offentliggjord eller inte allmÀnt kÀnd för att den skall kunna utgöra insiderinformation. I förarbeten, viss doktrin och domstolsavgöranden förutsÀtts att de bÄda uttrycken har samma innebörd. I uppsatsen intas stÄndpunkten att det rör sig om tvÄ skilda begrepp med olika innebörd samt att det krÀvs att informationen Àr bÄde icke offentliggjord och inte allmÀnt kÀnd för att den skall kunna utgöra insiderinformation. Den frÄga som har Àgnats mest utrymme i förarbeten och doktrin Àr prispÄverkanderekvisitet. I detta avseende analyseras förarbeten samt ett antal underinstansavgöranden. Analysen visar att innebörden av begreppet vÀsentlig prispÄverkan Àr svÄrbestÀmt och varierar mellan olika instrument och marknader och att domstolar ofta tar hÀnsyn till faktiska kursrörelser, istÀllet för att göra den erfarenhetsmÀssiga bedömning som följer av formuleringen ''Àgnad att''. DÀrutöver uppmÀrksammas problemet med att sÀrskilja en viss omstÀndighets prispÄverkan frÄn prispÄverkan av andra omstÀndigheter, dÀribland rykten. Uppsatsens slutsats Àr att det Àr svÄrt att faststÀlla nÄgot sÄ nÀr tydliga grÀnser för det straffbara omrÄdet avseende insiderinformation. Lagstiftningen Àr bristfÀllig pÄ ett sÀtt som inte Àr acceptabelt inom straffrÀtten. GenomgÄende Àr att lagstiftaren och domstolarna visar stor osÀkerhet och brist pÄ precision vad gÀller utformningen respektive tillÀmpningen av lagstiftningen. De olika delarna av begreppet insiderinformation Àr bristfÀlligt motiverade och tenderar att flyta samman. Lagstiftningens brister medför svÄrigheter bÄde för Äklagaren och för den tilltalade. SvÄrigheterna för Äklagaren bestÄr i att försöka utröna exakt vad det Àr som skall bevisas, d.v.s. att med tillrÀcklig precision reda ut hur rekvisiten egentligen ser ut. Detta medför att bÄde Ätal och domskÀl blir vaga och svepande, vilket i slutÀndan drabbar den tilltalade
Homocysteine and small vessel stroke: A mendelian randomization analysis.
OBJECTIVE: Trials of B vitamin therapy to lower blood total homocysteine (tHcy) levels for prevention of stroke are inconclusive. Secondary analyses of trial data and epidemiological studies suggest that tHcy levels may be particularly associated with small vessel stroke (SVS). We assessed whether circulating tHcy and B vitamin levels are selectively associated with SVS, but not other stroke subtypes, using Mendelian randomization. METHODS: We used summary statistics data for single-nucleotide polymorphisms (SNPs) associated with tHcy (nâ=â18), folate (nâ=â3), vitamin B6 (nâ=â1), and vitamin B12 (nâ=â14) levels, and the corresponding data for stroke from the MEGASTROKE consortium (nâ=â16,952 subtyped ischemic stroke cases and 404,630 noncases). RESULTS: Genetically predicted tHcy was associated with SVS, with an odds ratio of 1.34 (95% confidence interval [CI], 1.13-1.58; pâ=â6.7âĂâ10-4 ) per 1 standard deviation (SD) increase in genetically predicted tHcy levels, but was not associated with large artery or cardioembolic stroke. The association was mainly driven by SNPs at or near the MTHFR and MUT genes. The odds ratios of SVS per 1 SD increase in genetically predicted folate and vitamin B6 levels were 0.49 (95% CI, 0.34-0.71; pâ=â1.3âĂâ10-4 ) and 0.70 (95% CI, 0.52-0.94; pâ=â0.02), respectively. Genetically higher vitamin B12 levels were not associated with any stroke subtype. INTERPRETATION: These findings suggest that any effect of homocysteine-lowering treatment in preventing stroke will be confined to the SVS subtype. Whether genetic variants at or near the MTHFR and MUT genes influence SVS risk through pathways other than homocysteine levels and downstream effects require further investigation. Ann Neurol 2019;85:495-501
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