Counterexamples regarding Symmetric Tensors and Divided Powers

We investigate the similarities and differences between the module of symmetric tensors TS^n_A(M) and the module of divided powers \Gamma^n_A(M). There is a canonical map \Gamma^n_A(M) \to TS^n_A(M) which is an isomorphism in many important cases. We give examples showing that this map need neither be surjective nor injective in general. These examples also show that the functor TS_A^n does not in general commute with base change.Comment: 22 pages. Updates: Added new section 7, added remarks regarding extension to general characteristic p>0. To appear in Journal of Pure and Applied Algebr

Human African trypanosomiasis

Human African trypanosomiasis (sleeping sickness) occurs in sub-Saharan Africa. It is caused by the protozoan parasite Trypanosoma brucei, transmitted by tsetse flies. Almost all cases are due to Trypanosoma brucei gambiense, which is indigenous to west and central Africa. Prevalence is strongly dependent on control measures, which are often neglected during periods of political instability, thus leading to resurgence. With fewer than 12 000 cases of this disabling and fatal disease reported per year, trypanosomiasis belongs to the most neglected tropical diseases. The clinical presentation is complex, and diagnosis and treatment difficult. The available drugs are old, complicated to administer, and can cause severe adverse reactions. New diagnostic methods and safe and effective drugs are urgently needed. Vector control, to reduce the number of flies in existing foci, needs to be organised on a pan-African basis. WHO has stated that if national control programmes, international organisations, research institutes, and philanthropic partners engage in concerted action, elimination of this disease might even be possible

European survey on laboratory preparedness, response and diagnostic capacity for crimean-congo haemorrhagic fever, 2012

Crimean-Congo haemorrhagic fever (CCHF) is an infectious viral disease that has (re-)emerged in the last decade in south-eastern Europe, and there is a risk for further geographical expansion to western Europe. Here we report the results of a survey covering 28 countries, conducted in 2012 among the member laboratories of the European Network for Diagnostics of 'Imported' Viral Diseases (ENIVD) to assess laboratory preparedness and response capacities for CCHF. The answers of 31 laboratories of the European region regarding CCHF case definition, training necessity, biosafety, quality assurance and diagnostic tests are presented. In addition, we identifi

Moduli spaces of zero-dimensional geometric objects

The topic of this thesis is the study of moduli spaces of zero-dimensional geometricobjects. The thesis consists of three articles each focusing on a particular moduli space.The first article concerns the Hilbert scheme Hilb(X). This moduli space parametrizesclosed subschemes of a fixed ambient scheme X. It has been known implicitly for sometime that the Hilbert scheme does not behave well when the scheme X is not separated.The article shows that the separation hypothesis is necessary in the sense thatthe component Hilb1(X) of Hilb(X) parametrizing subschemes of dimension zero andlength 1 does not exist if X is not separated.Article number two deals with the Chow scheme Chow 0,n(X) parametrizing zerodimensionaleffective cycles of length n on the given scheme X. There is a relatedconstruction, the Symmetric product Symn(X), defined as the quotient of the n-foldproduct X ×. . .×X of X by the natural action of the symmetric group Sn permutingthe factors. There is a canonical map Symn(X) " Chow0,n(X) that, set-theoretically,maps a tuple (x1, . . . , xn) to the cycle!nk=1 xk. In many cases this canonical map is anisomorphism. We explore in this paper some examples where it is not an isomorphism.This will also lead to some results concerning the question whether the symmetricproduct commutes with base change.The third article is related to the Fulton-MacPherson compactification of the configurationspace of points. Here we begin by considering the configuration space F(X, n)parametrizing n-tuples of distinct ordered points on a smooth scheme X. The schemeF(X, n) has a compactification X[n] which is obtained from the product Xn by a sequenceof blowups. Thus X[n] is itself not defined as a moduli space, but the pointson the boundary of X[n] may be interpreted as geometric objects called stable degenerations.It is then natural to ask if X[n] can be defined as a moduli space of stabledegenerations instead of as a blowup. In the third article we begin work towards ananswer to this question in the case where X = P2. We define a very general modulistack Xpv2 parametrizing projective schemes whose structure sheaf has vanishing secondcohomology. We then use Artin’s criteria to show that this stack is algebraic. Onemay define a stack SDX,n of stable degenerations of X and the goal is then to provealgebraicity of the stack SDX,n by using Xpv2.QC 2010072

The stack of projective schemes with vanishing second cohomology

Preprint 200

The stack of projective schemes with vanishing second cohomology

Preprint 200

Tufft med luft : Kompressorinstallation i laborationssyfte

The project was commissioned by Tobias Hedin, who is a lecturer at the Kalmar Maritime Academy. The mission was to install a physical compressor facility that would replace an existing graphic simulator. The goal of the assembly was also, to the extent where it was possible, to emulate the compressor plants onboard ships. With the help of literary studies, but also through own experience, the necessary data were developed around compressors and facilities on board. The final choice of compressor was also done with regard to the budget, noise and capacity. Apart from the compressors, the budget also included the purchase of some peripherals that were necessary to adapt the compressor to the task. The Maritime Academy provided drawing program for schedules, and also electrical supplies. The work resulted in a fully functional compressor system with a control cabinet and control system. The client also received documentation of the facility.Projektet utfördes på uppdrag av Tobias Hedin som är universitetsadjunkt vid Sjöfartshögskolan i Kalmar. Utbildningen, för Sjöingenjörerna vid Sjöfartshögskolan, innehåller en praktisk kurs kallad Tillämpad Elteknik. Ett av delmomenten i kursen är en programmeringsuppgift, vilken bestod av att med hjälp av en grafisk simulator programmera två kompressorer att gå enligt vissa villkor. Uppdraget var att installera en fysisk kompressoranläggning som skulle ersätta den befintliga grafiska simulatorn. Målet med anordningen var även att i den mån det var möjligt efterlikna de kompressoranläggningar som finns ombord på fartyg, då kursen Tillämpad Elteknik riktar sig till sjöingenjörsstudenter. Med hjälp av litteraturstudier, men också genom egen erfarenhet, togs fakta fram kring kompressorer och anläggningar ombord. Genom fakta från litteraturstudierna gjordes först val av kompressor. Detta gjordes med hänsyn till budget, bullernivå och kapacitet. I budgeten ingick även inköp av en del kringutrustning som var nödvändig för att anpassa kompressorerna till uppgiften. Sjöfartshögskolan tillhandahöll ritprogram för scheman, och även materiel som redan fanns tillgängligt i Trångsundet. Arbetet resulterade i en fullt fungerande kompressoranläggning med manöverskåp och styrsystem. Beställaren fick också dokumentation över anläggningen

ROMA - State assessment of road markings in Denmark, Nor-way and Sweden : Results from 2018

Assessments of the performance of road markings is carried out regularly to various degrees in the Nordic countries. The main aim of the Nordic road marking assessment study is to show possible differences in road marking performance between Denmark, Norway and Sweden. Possible differences between road marking performance, dependent on region, country, type of road and AADT (Annual Average Daily Traffic) are studied. Furthermore, a comparison between the TEN-T and the non-TEN-T road network is made. As 2018 is the second year of the project, a comparison between the results for 2017 and 2018 is also made. A Nordic certification system for road marking materials has recently been introduced in Norway and Denmark and will be introduced in Sweden 2019. This means that a documented product approval (i.e. certification) will be required for use of the material on roads managed by the national road authorities. The requirements are introduced successively as the existing contracts expire. Therefore, one aim is also to study the road marking quality before and under the introduction of the new certification requirements. Continuous assessments give the opportunity to react and adjust the requirements in the future, if the performance does not develop as expected. The study is based on physical mobile road assessment measurements carried out in Denmark, Norway and Sweden by Ramböll. In total 71 road objects were measured in Denmark, 124 in Norway and 434 in Sweden. The following variables were studied: retroreflectivity of dry and wet road markings, relative visibility of dry and wet road markings, relative pre-view-time (pvt) of dry and wet road markings and cover index. Vägmarkeringarnas tillstånd studeras regelbundet i olika omfattning i de nordiska länderna. Det huvudsakliga syftet med föreliggande studie är att med tillståndmätningar visa på eventuella skillnader avseende vägmarkeringsprestanda mellan Danmark, Norge och Sverige. Då 2018 är projektets andra år, görs även en jämförelse mellan resultaten mellan 2017 och 2018. Ett nordiskt certifieringssystem för vägmarkeringsmaterial har nyligen införts i Norge och Danmark och kommer att införas i Sverige under 2019. Detta innebär att ett dokumenterat produktgodkännande (certifiering) kommer att krävas för att materialet ska få användas på vägar som förvaltas av de nationella vägmyndigheterna. De nya kraven införs succesivt efter att de befintliga entreprenaderna löper ut. Ett annat syfte med föreliggande studie är därför att få en bra bild av vägmarkeringarnas funktion dels innan det nya certifieringssystemet börjar tillämpas, dels att med fortsatta mätningar under 2019 – 2021 studera utvecklingen och effekterna av certifieringens införande. Studien baseras på fysikaliska mobila tillståndsmätningar utförda i Danmark, Norge och Sverige av Ramböll. Totalt mättes 71 vägobjekt i Danmark, 124 i Norge och 434 i Sverige. Följande variabler studerades: retroreflexion för torra och våta vägmarkeringar, relativ synbarhet för torra och våta vägmarkeringar, relativ pre-view-time (pvt) för torra och våta vägmarkeringar samt vägmarkeringens täckningsgrad