Gradient methods for iterative distributed control synthesis

In this paper we present a gradient method to iteratively update local controllers of a distributed linear system driven by stochastic disturbances. The control objective is to minimize the sum of the variances of states and inputs in all nodes. We show that the gradients of this objective can be estimated distributively using data from a forward simulation of the system model and a backward simulation of the adjoint equations. Iterative updates of local controllers using the gradient estimates gives convergence towards a locally optimal distributed controller

Healing of sugar beets in field after frost : a case study at Hviderup 2016

Sockerbetsodlingen i Sverige utsätts för stora prövningar på grund av det hårda vinterklimatet som kan råda i de norra delarna i Europa. Alla betor från ca 35 000 hektar processas på sockerbruket i Örtofta, vilket är beläget i mellersta delarna av Skåne. Detta medför en lång kampanj som kan sträcka sig in i februari månad när vintern är som kallast. Sockerbetan är frostkänslig och fryser vid -2°C till -4°C, under dessa temperaturer försvåras processen i sockerbruket på grund av att sackarosen i betan bryts ner till de enkla sockerarterna glukos och fruktos, så kallat invertsocker. Under första hälften av november 2016 var en fjärdedel av betarealen oskördad, då kom frost som höll i sig i en vecka med temperaturer ner mot -10°C. Informationen var bristfällig beträffande hur odlare skulle hantera situationen då forskningen inom detta område är begränsad. I Europa hävdas generellt att sockerbetorna ska skördas direkt efter frost innan de hinner tina för att bli levererade till sockerbruken. Alltmedan det i Nordamerika sägs att betorna ska få chans att läka innan de skördas. Detta examensarbete har gått ut på att undersöka om sockerbetor i ett fält kan läka under de omständigheter som rådde under november och december 2016. Sockerbetorna skördades vid sex olika tillfällen, hälften av dem lagrades medan övriga direkt levererades till Örtofta sockerbruk för analys. De lagrade betorna förvarades i provlådor i en maskinhall för att sedan analyseras strax innan sockerbruket stängde. De graderades då okulärt innan de skickades för analys. Resultatet i min studie visar att sockerbetan har en tendens att läka efter den första frostknäppen, dock inte med signifikans. Samma tendens syntes på de betor som lagrats. Resultaten visar att den andra frostknäppen som kom i slutet på november gav signifikant påverkan på betornas sockerhalt och lagringsduglighet. Sockerhalten sjönk signifikant under försöksperioden i både de direktlevererade och lagrade leden. Mest sjönk sockerhalten i de lagrade ledens två sista skördar, detta trots att de utsattes för färre daggrader. Ett viktigt resultat från studien är att renheten på detta fält (23 % Ler) varierar mycket efter väderomständigheterna. På knappt två veckor (18/11 – 1/12) med bra väder så ökade renheten från 80 till 90 %. Det ekonomiska utfallet visade på att det vid alla omständigheter är mer lönsamt att skörda betorna innan frost än att låta dem stå oskördade. Om odlaren har betor kvar i marken och det inte varit frost en längre period som har orsakat för stora skador på betorna så kan de läka i fält, men de bör tas upp innan nästa frost. Sockerbetan klarar sig relativt bra vid första frostknäppen om blasten är frisk då den ger en isolerande effekt. Vid den andra frostknäppen var blasten död, vilket sannolikt spelade stor roll då skadorna blev betydligt större på betorna. Nackhöjden på betan spelar också stor roll, då lågvuxna betor inte har lika stor yta som exponeras för den kalla luften och skadorna var således mindre i dessa. Gården som försöken var placerade på gjorde rätt i att plocka upp sina betor innan första frosten och undvek en förlust med 1 000–3 900 kr per hektar som det hade inneburit att utsätta betorna för en alternativt två frostknäppar. Examensarbetet har med hjälp av egna försök och litteraturstudier kommit fram till följande slutsatser: - Det finns tendenser till att en sockerbeta utsatt för frost kan läka, dock krävs vidare studier för att kunna styrka detta samband. - Vid frost påverkas sockerhalten i betan negativt. - Även en frostskadad beta går att lagra med goda resultat, om den lagras torrt och svalt. - En sockerbeta som lagras under fördelaktiga förhållanden har liknande tendenser vad gäller läkningen som en oskördad sockerbeta. - Under rådande omständigheter var det ekonomiskt mest lönsamt för odlaren att plocka upp betorna före frostangrepp. - Det finns tendenser (p<0,083) till ökade svampangrepp vid lång lagring i denna studie. - Upptagningsförhållanden spelar stor roll på renheten och på tyngre jordar kan skillnader på 10 procentenheter i renhet skilja på knappt två veckor vid olika väderlekar.The sugar beet cultivation in Sweden is exposed to a tough climate. All sugar beets from an area of 35 000 hectares are processed in the same factory which is placed in the middle of Skåne, in the very south of Sweden. Due to this, the delivery period of sugar beets to the factory is very long, some years lasting from September to February. This far north in Europe the low temperatures during winter creates a challenging environment for the sugar beet. A sugar beet has its freezing point between -2 and -4°C, when the beet freezes the sugar content is altered, causing problems with the sugar production in the factory. Most of the sugar beets are harvested before the temperature reaches a point of 0°C or lower, but around 25 percent of the sugar beets in the area were still not harvested when a frost came with temperatures down to -10°C in early November of 2016. There is not much research done on sugar beet harvest during these circumstances, and therefore not much information was available for the farmers on how to manage the situation. In Europe, the farmers are advised to harvest and deliver the frozen sugar beets before they are thawing, while the general advice in north America is for the farmers to wait a few days to give the beet a chance to heal in the soil before harvest. The purpose of this study is to investigate if sugar beets can heal after being exposed to temperatures below freezing point, considering the circumstances present at the harvesting period of 2016. Sugar beets were harvested six times and each time, half of the beets was delivered directly to the factory and the other half was stored in a nontemperate storage facility. The temperature of the stored samples were checked right before delivery to a sampling facility placed at Örtofta sugar factory. The sugar beets were later analyzed based on sugar, dry matter, invert sugar, sodium, calcium, and amino-N content. There were some indications that a sugar beet could heal in the soil after being exposed to the first period of frost, but in order to statistically confirm this trend further studies are needed. After the second period of frost, the sugar beets showed no signs of recovering. The results showed that the sugar content significantly decreased during the study period in the sugar beets, regardless if they were sent directly to the factory or stored in a non-temperate storage facility. The stored samples from the last two harvests decreased in sugar content even though they had least day level degrees. One of the main findings in this study were the difference in the level of purity between sugar beets that derived from the same field (23% loam), after two weeks of dry weather conditions the purity in the sugar beet samples increased from 80% to 90%. The economic calculations showed that it was always more profitable for the farmer to harvest the sugar beets before frost. The sugar beets are not affected to a great extent by the first period of frost if the beet tops are in good shape, as the beet tops provide insulation to the sugar beet. During the second period of frost, the beet tops were no longer viable, which is a probable cause of the increase in damage to the sugar beets at that period of time. Furthermore, the results showed that the height of the beet root over the soil surface had an impact on the severity of the damages caused by frost, as sugar beets with less surface area above soil were more also less exposed to the cold temperatures. By harvesting the sugar beets before the first frost, the farm on which the field trials were performed avoided a loss between approximately 1 000-3 900 SEK/hectare. The following conclusions have been made based on the results of the field study and literature research: - There are indications of sugar beets being able to heal after being exposed to frost, but further studies are needed to validate these findings - Frost has a significant affected to the sugar content in sugar beets - Sugar beets damaged by frost can be stored with good results if stored dry and cold - A sugar beet that has been stored under favorable conditions have the same possibilities to heal, as a sugar beet that is still in the soil - In this study, it was most profitable for the farmer to harvest the sugar beets before the temperature reaches a point of 0 � or lower - There is a tendency of increased occurrence of mold in stored sugar beets that were harvested early (p<0,083) - The climatic conditions during harvest has a big impact on the purity of the sugar beet yield, only two weeks of dry weather increased the purity by 10

Teaching of chemical bonding: a study of Swedish and South African students' conceptions of bonding

Almost 700 Swedish and South African students from the upper secondary school and first-term chemistry university level responded to our survey on concepts of chemical bonding. The national secondary school curricula and most common textbooks for both countries were also surveyed and compared for their content on chemical bonding. Notable differences between the countries were found in textbooks and in the curriculum regarding the topics of ionic bonding, bond energetics and use of the VSEPR model, the latter being absent in the Swedish curriculum and ionic bonding not explicitly mentioned in the South African curriculum. To some extent these differences are reflected in the students' responses to the survey. It is also clear that university teachers in both countries must prepare effective counter-measures against deep rooted misunderstandings. For the upper secondary school level it is suggested that the bond energetics and exothermic and endothermic reactions be clearly and carefully presented and separated as the study indicates that mixing of these two concepts is a major cause of confusion

Unexpected selections of Plasmodium falciparum polymorphisms in previously treatment-naïve areas after monthly presumptive administration of three different anti-malarial drugs in Liberia 1976-78.

BACKGROUND: To assess the effect on malaria prevalence, village specific monthly administrations of pyrimethamine, chlorproguanil, chloroquine or placebo were given to children in four previously treatment-naïve Liberian villages, 1976-78. Plasmodium falciparum in vivo resistance developed to pyrimethamine only. Selection of molecular markers of P. falciparum resistance after 2 years of treatment are reported. METHODS: Blood samples were collected from 191 study children in a survey in 1978. Polymorphisms in pfcrt, pfmdr1, pfdhfr, pfdhps, pfmrp1 and pfnhe1 genes were determined using PCR-based methods. RESULTS: Pfcrt 72-76 CVIET was found in one chloroquine village sample, all remaining samples had pfcrt CVMNK. Pfmdr1 N86 prevalence was 100%. A pfmdr1 T1069ACT→ACG synonymous polymorphism was found in 30% of chloroquine village samples and 3% of other samples (P = 0.008). Variations in pfnhe1 block I were found in all except the chloroquine treated village (P < 0.001). Resistance associated pfdhfr 108N prevalence was 2% in the pyrimethamine village compared to 45-65% elsewhere, including the placebo village (P = 0.001). CONCLUSIONS: Chloroquine treatment possibly resulted in the development of pfcrt 72-76 CVIET. Selection of pfmdr1 T1069ACG and a pfnhe1 block 1 genotypes indicates that chloroquine treatment exerted a selective pressure on P. falciparum. Pyrimethamine resistance associated pfdhfr 108N was present prior to the introduction of any drug. Decreased pfdhfr 108N frequency concurrent with development of pyrimethamine resistance suggests a non-pfdhfr polymorphisms mediated resistance mechanism

Patients´ Experiences of Pain Following Day Surgery - At 48 Hours, Seven Days and Three Months

Recent studies indicate that patients experience pain after day surgery for a longer period than previously known. This requires verification. This was a prospective, descriptive correlational study. A convenience sample of 298 day surgery patients undergoing various surgical procedures was asked to report pain intensity and its interference with daily function 48 hours, seven days and three months after day surgery. Correlation and regression analyses were performed. On a NRS, 55% (n=230) reported pain (≥4) 48 hours after surgery, as did 43% (n=213) at seven days. Pain interfered with normal activities at ≥4 NRS at 48 hours and at seven days, after which it decreased

Pedagogisk utbildning i ett utvecklingsperspektiv

Behörighetsgivande högskolepedagogisk utbildning har nu blivit verklighet runt om i landet. Det finns från flera håll en stark förhoppning om att sådan utbildning ska bidra till att undervisningen utvecklas. Samtidigt kostar dessa kurser både pengar och tid, något som kanske går ut över andra utvecklingsinitiativ. Det är därför extra viktigt att ha ett utvecklingsperspektiv vid planering och genomförande av dessa kurser. Hur kan ett sådant perspektiv se ut? Det finns idag en ökande medvetenhet om hur det sociala sammanhang lärare befinner sig i kan begränsa alternativt möjliggöra utveckling av undervisningen. Trowler & Cooper (2002) definierar det sociala sammanhanget med en beskrivning av teaching and learning regimes (TLR) bestående av ett antal kulturella komponenter vilka påverkar lärares upplevelser och agerande i och runt undervisningen. Ett utvecklingsperspektiv på högskolepedagogisk utbildning bör därför innebära tankar inte bara om hur individer ska utvecklas utan också om hur kurserna ska bidra till att det sociala sammanhanget och dess TLR kan utvecklas. Vi menar att detta perspektiv lätt förbises. Själva begreppet behörighetsgivande är i detta sammanhang problematiskt. Det signalerar att utbildningen gör någon behörig till ett sammanhang – inte att sammanhanget bör utvecklas! Detta rundabordsamtal syftar till att fördjupa diskussionen kring utmaningen att utveckla både individer och det sammanhang de ingår i. Vi hävdar att högskolepedagogisk utbildning måste ses som en del i en strategi som syftar till utveckling av undervisningen inom den högre utbildningen

CYP2C8 status of patients with malaria influences selection of Plasmodium falciparum pfmdr1 Alleles after Amodiaquine-Artesunate treatment

info:eu-repo/semantics/publishedVersio

Decreased Prevalence of Plasmodium Falciparum Resistance Markers to Amodiaquine Despite its wide Scale use as ACT Partner Drug in Zanzibar.

Zanzibar has recently undergone a rapid decline in Plasmodium falciparum transmission following combined malaria control interventions with artemisinin-based combination therapy (ACT) and integrated vector control. Artesunate-amodiaquine (ASAQ) was implemented as first-line treatment for uncomplicated P. falciparum malaria in Zanzibar in 2003. Resistance to amodiaquine has been associated with the single nucleotide polymorphism (SNP) alleles pfcrt 76T, pfmdr1 86Y, 184Y and 1246Y. An accumulation of these SNP alleles in the parasite population over time might threaten ASAQ efficacy.The aim of this study was to assess whether prolonged use of ASAQ as first-line anti-malarial treatment selects for P. falciparum SNPs associated with resistance to the ACT partner drug amodiaquine. The individual as well as the combined SNP allele prevalence were compared in pre-treatment blood samples from patients with uncomplicated P. falciparum malaria enrolled in clinical trials conducted just prior to the introduction of ASAQ in 2002-2003 (n = 208) and seven years after wide scale use of ASAQ in 2010 (n = 122). There was a statistically significant decrease of pfcrt 76T (96-63%), pfmdr1 86Y (75-52%), 184Y (83-72%), 1246Y (28-16%) and the most common haplotypes pfcrt/pfmdr1 TYYD (46-26%) and TYYY (17-8%), while an increase of pfcrt/pfmdr1 KNFD (0.4-14%) and KNYD (1-12%). This is the first observation of a decreased prevalence of pfcrt 76T, pfmdr1 86Y, 184Y and 1246Y in an African setting after several years of extensive ASAQ use as first-line treatment for uncomplicated malaria. This may support sustained efficacy of ASAQ on Zanzibar, although it was unexpected considering that all these SNPs have previously been associated with amodiaquine resistance. The underlying factors of these results are unclear. Genetic dilution by imported P. falciparum parasites from mainland Tanzania, a de-selection by artesunate per se and/or an associated fitness cost might represent contributing factors. More detailed studies on temporal trends of molecular markers associated with amodiaquine resistance are required to improve the understanding of this observation