847 research outputs found

    Didactic and Curriculum in ECEC from a Froebelian standpoint

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    How can we use Friedrich Froebel’s play theory in order to analyze ECEC, Early Childhood Education and Care? Wolfgang Klafki builds his theory of categorical Bildung on Froebel’s play theory, which presupposes the interaction between child, adult and content, as in the didactic triangle. Froebel’s play theory was lost in the hands of his followers Bertha von Marenholtz-BĂŒlow and Henriette Schrader-Breymann. Developmental theories such as the cultural level theory and the recapitulation theory had a strong influence. One result was a child-centered laissez-faire pedagogy, waiting for the child to mature enough to be able to start school. With Klafki and his perspective on Froebel, it is possible to ask a set of questions in order to describe and analyze contemporary ECEC programs: (i) What are the didactic relations between child, adult and content, as in the didactic triangle? (ii) What is the content and how is it selected and organized? (iii) What kind of play and learning is intended

    VÀxtnÀring frÄn trekammarbrunnar till energigrÀs

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    En slutsats som dragits inom projektet Ă€r att sjĂ€lva kretsloppet för vĂ€xtnĂ€ringsinnehĂ„llet i trekammarbrunnsslam inte Ă€r den viktigaste frĂ„gan ur hĂ„llbarhetssynpunkt vid odling av energigrĂ€s, eftersom Ă„terföringen av vĂ€xtnĂ€ring med trekammarbrunnsslam, frĂ€mst fosfor och kalium, Ă€r mycket begrĂ€nsad. I stĂ€llet Ă€r sjĂ€lva nyttjandet av energigrĂ€set som rĂ„vara för produktion av förnybara drivmedel mycket viktigare ur hĂ„llbarhetssynpunkt. HĂ„llbarheten i systemet ligger i att energigrĂ€set kan omvandlas till förnybara drivmedel, sĂ„som biogas och bioetanol, vilka ersĂ€tter bensin och diesel, som har en mycket stor klimatpĂ„verkan. Enligt litteraturuppgifter ger en vallgröda pĂ„ ca 9 ton torrsubstans (ts) per ha och Ă„r, en reduktion av vĂ€xthusgasemissioner med ca 6 ton CO2-ekv. per hektar och Ă„r, under förutsĂ€ttning att fordonsgas i form av metan produceras av vallgrödan och biogödseln, som kvarstĂ„r efter rötningen av vallgrödan, ersĂ€tter mineralgödsel pĂ„ produktiv Ă„kermark. Inom projektet har vi uppnĂ„tt skördar pĂ„ 5 - 15 ton ts per ha och Ă„r beroende pĂ„ odlingslokal och vilket energigrĂ€s som odlats, om grĂ€set varit gödslat eller ogödslat samt om baljvĂ€xter ingĂ„tt i ”biogasvallen”. SkördenivĂ„er i detta intervall tyder pĂ„ att man kan uppnĂ„ ett hĂ„llbart system för produktion av biogas baserat pĂ„ energigrĂ€s, enligt EU:s nuvarande hĂ„llbarhetskriterier (en CO2-reduktion pĂ„ minst 35 %) för förnybara drivmedel, oberoende om grĂ€set gödslas med trekammarbrunnsslam eller ej. SĂ€rskilt stor klimatnytta uppnĂ„s vid anvĂ€ndning av biogasvallar som innehĂ„ller bĂ„de grĂ€s och baljvĂ€xter, eftersom dessa ger hög biomassaavkastning helt utan kvĂ€vegödsling. Biogaspotentialen hos de energigrĂ€s och biogasvallar som studerats i projektet ligger normalt i intervallet 250 – 350 l CH4 per kg VS, beroende pĂ„ skördetidpunkt och förbehandlingsmetod. Att anvĂ€nda energiĂ„krar för odling av flerĂ„riga energigrĂ€s dĂ€r biomassan anvĂ€nds för produktion av biogas, bioetanol eller fastbrĂ€nsle innebĂ€r flera miljövinster, mest pĂ„tagligt genom minskad klimatpĂ„verkan, eftersom fossil energi ersĂ€tts, men Ă€ven genom att flerĂ„riga grödor har lĂ€gre behov av insatser i form av jordbearbetning och ogrĂ€sbekĂ€mpning och lagrar in mer kol i rötterna och marken Ă€n ettĂ„riga grödor. Ytterligare miljövinster kan erhĂ„llas om biomassa skördas pĂ„ ogödslade energiĂ„krar nĂ€ra kĂ€nsliga vattenmiljöer, eftersom man dĂ„ kan transportera bort vĂ€xtnĂ€ring till produktiv Ă„kermark, som annars skulle kunna orsaka övergödning. Vid anvĂ€ndning av energigrĂ€s som biogassubstrat kan biogödseln, som blir kvar efter rötningen, anvĂ€ndas som ett vĂ€rdefullt gödselmedel inom ekologisk eller konventionell odling. Biogödseln innehĂ„ller lĂ€ttillgĂ€nglig vĂ€xtnĂ€ring och om den anvĂ€nds för gödsling av livsmedelsgrödor pĂ„ Ă„kermark sker en stor miljövinst genom ersĂ€ttning av mineralgödsel. För att trekammarbrunnsslam skall kunna anvĂ€ndas som ett gödselmedel till energigrĂ€s sĂ„ krĂ€vs det en hygienisering genom t.ex. tillsats av minst 0,6 % urea och lagring i minst 3 mĂ„nader. Hygienisering med urea medför dock att trekammarbrunnsslammet fĂ„r ett relativt högt kvĂ€veinnehĂ„ll i jĂ€mförelse med andra viktiga vĂ€xtnĂ€ringsĂ€mnen, sĂ„som fosfor och kalium. Detta innebĂ€r att fosfor och kalium mĂ„ste tillföras med andra gödselmedel för att energiĂ„kern inte skall lida brist pĂ„ dessa vĂ€xtnĂ€ringsĂ€mnen pĂ„ lĂ€ngre sikt. Tillförseln av tungmetaller med det hygieniserade trekammarbrunnsslammet till energiĂ„kern bedöms vara nĂ„got större jĂ€mfört med om kĂ€llsorterat klosettvatten eller nötflytgödsel anvĂ€nds som gödselmedel till energigrĂ€sen. Halterna av miljöstörande organiska Ă€mnena i trekammarbrunnsslam ligger dock lĂ„ngt under riktvĂ€rdena för avloppsslam enligt slamöverenskommelsen. Allt detta visar att hygieniserat trekammarbrunnsslam kan anvĂ€ndas som en vĂ€xtnĂ€ringsresurs vid odling av energigrĂ€s eller biogasvallar pĂ„ energiĂ„krar, men att hygieniserat klosettvatten skulle vara ett vĂ€l sĂ„ bra alternativ

    The Influence of KCl and HCl on the High-Temperature Oxidation of a Fe-2.25Cr-1Mo Steel at 400\ua0\ub0C

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    The influence of alkali- and chlorine-containing compounds on the corrosion of superheater alloys has been studied extensively. The current paper instead investigates the corrosive effects of KCl and HCl under conditions relevant to waterwall conditions. A low-alloy (Fe-2.25Cr-1Mo) steel was exposed to KCl(s), 500\ua0vppm HCl(g) and (KCl + HCl) in the presence of 5%O2 and 20% H2O at 400\ua0\ub0C. The results indicate that alloy chlorination by KCl occurs by an electrochemical process, involving cathodic formation of chemisorbed KOH on the scale surface and anodic formation of solid FeCl2 at the bottom of the scale. The process is accompanied by extensive cracking and delamination of the iron oxide scale, resulting in a complex, convoluted scale morphology. Adding 500\ua0vppm HCl to the experimental environment (KCl + HCl) initially greatly accelerated the formation of FeCl2 at the scale/alloy interface. The accelerated alloy chlorination is attributed to HCl reacting with KOH at the scale surface, causing the cathodic process to be depolarized. A rapid slowing down of the rate of chlorination and corrosion in KCl + HCl environment was observed which was attributed to the electronically insulating nature of the FeCl2 layer which forms at the bottom of the scale, disconnecting the anodic and cathodic regions

    Risk of obesity in immigrants compared with Swedes in two deprived neighbourhoods

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    <p>Abstract</p> <p>Background</p> <p>Despite a strong social gradient in the prevalence of obesity, there is little scientific understanding of obesity in people settled in deprived neighbourhoods. Few studies are actually based on objectively measured data using random sampling of residents in deprived neighbourhoods. In addition, most studies use a crude measure, the body mass index, to estimate obesity. This is of concern because it may cause inaccurate estimations of the true prevalence and give the wrong picture of the factors associated with obesity. The aim of this study was to estimate the prevalence of, and analyse the sociodemographic factors associated with, three indices of obesity in different ethnic groups settled in two deprived neighbourhoods in Sweden.</p> <p>Methods</p> <p>Height and weight, waist circumference and body fat percentage were objectively measured in a random sample (n = 289). Sociodemographic data were obtained through a survey. Established cut-offs were used to determine obesity. Country of birth was categorized as Swedish, Other European, and Middle Eastern. Odds ratios were estimated by unconditional logistic regression.</p> <p>Results</p> <p>One third of the sample was classified as obese overall, with 39.0% of women being abdominally obese. After adjusting for age, we found higher odds of obesity in Middle Eastern women than in Swedish women regardless of outcome with odds ratios ranging between 2.74 and 5.53. Men of other European origin had higher odds of BMI obesity than Swedish men. Most associations between country of birth and obesity remained in the full model.</p> <p>Conclusion</p> <p>This study demonstrates the magnitude of the obesity problem and the need for prevention programmes targeting native and immigrant adults in deprived neighbourhoods in Sweden. The initiatives should also focus on particular groups, e.g. immigrant women and those experiencing economic difficulties. Further studies are needed on behavioural and environmental factors influencing the risk of obesity in residents settled in deprived neighbourhoods.</p

    Cage environment and fish welfare

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    This survey give detailed information about the complex variation of the physical, biological and chemical variation in environment at typical fjord and coastal farming sites in the autumn. Large variations with depth and time were seen within the same farm. Water current direction and speed at a reference point outside a farm was not representative for the current seen close to the cages. Current reduction and deflection caused by the cages affected the oxygen levels within cages. Large variation in swimming depth and observed fish density was seen. Through site and technology choice, farmed fish must be offered an environment that secure fish weifare. NORSK SAMMENDRAG: Denne undersÞkelsen gir detaljerte Þyeblikksbilder av en kompleks variasjon i fysiske, biologiske og kjemiske miljÞfaktorer pÄ typiske kyst- og fjordlokaliteter om hÞsten. Det var store variasjoner i de fleste miljÞfaktorer innenfor ett og samme anlegg bÄde over dyp og tid. HovedstrÞmretning og strÞmhastighet i et referansepunkt ved en lokalitet sier lite om det reelle strÞmbildet ved merdene. Demping og avbÞyning av vannstrÞm forÄrsaket av anlegget har store konsekvenser for oksygenmetningen i merdene. Variasjonen i svÞmmedyp og observert fisketetthet var stor. Resultatene illustrerer at lakseproduksjon i merder i sterk grad foregÄr pÄ naturens premisser. Oppdrettsfisk mA tilbys miljÞforhoid som sikrer god fiskevelferd gjennom valg av lokaliet og anleggsutforming

    Cardiovascular risk factors in Assyrians/Syrians and native Swedes with type 2 diabetes: a population-based epidemiological study

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    <p>Abstract</p> <p>Background</p> <p>A large number of people throughout the world have diabetes and the prevalence is increasing. Persons with diabetes have a twice higher risk of cardiovascular disease than those without diabetes. There is a lack of studies focusing on cardiovascular risk factors in Assyrians/Syrians with type 2 diabetes. The aim of this study is to estimate the prevalence of some cardiovascular risk factors among Assyrians/Syrians and native Swedes with type 2 diabetes and to study whether the association between ethnicity and cardio-vascular risk factors remains after adjustment for age, gender, employment status and housing tenure.</p> <p>Methods</p> <p>In the Swedish town of SödertÀlje 173 Assyrians/Syrians and 181 ethnic Swedes with type 2 diabetes participated in a study evaluating cardiovascular risk factors such as increased haemoglobin A1c (HbA1c), high blood lipids (total serum cholesterol and triglycerides), hypertension and high urinary albumin. The associations between the outcome variables and sociodemographic characteristics were estimated using unconditional logistic regression.</p> <p>Results</p> <p>The prevalence of increased triglycerides in Swedish-born subjects and Assyrian-Syrians was 61.5% and 39.7% respectively. Swedes had a prevalence of hypertension 76.8% compared to 57.8% in Assyrians/Syrians. In the final logistic models adjusted for gender, age, housing and employment the odds ratio (OR) for Swedish-born subjects for increased triglycerides was 2.80 (95% CI1.61-4.87) and for hypertension 2.32 (95% CI 1.35-4.00) compared to Assyrians-Syrians.</p> <p>Conclusion</p> <p>Ethnic Swedes had higher prevalence of increased triglycerides and hypertension than Assyrians/Syrians. Total cholesterol, HbA1c and urinary albumin did not differ between the two ethnic groups.</p

    Överbyggnad - utformning vid belĂ€ggning av natursten och markbetong

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    FörstÄ! Gör rÀtt! Spara hundratals miljoner kronor för Àgare av urbana ytor! SÄ lyder vÄrt huvudbudskap i detta Movium Fakta, som pÄ ett kortfattat och elementÀrt sÀtt behandlar överbyggnad med belÀggning av natursten och markbetong i stadsliknande miljöer

    Överbyggnad med belĂ€ggning av natursten och markbetong, för trafikklass ≀ 2 : förenklad dimensionering för stadsliknande miljöer

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    Feldimensionerad överbyggnad, felaktiga material, fel kombination av material och felaktigt utförande kommer att, med tiden, visa sig som spÄrbildningar, ojÀmnheter, sÀttningar, tjÀllyftningar, osv pÄ ytan av markbelÀggningen. I bÀsta fall visar sig skadorna tidigt under garantitiden dÄ det fortfarande finns en affÀrsrelation mellan entreprenör, konstruktör och byggherre/bestÀllare, och dÄ det fortfarande finns en möjlighet till att utreda och ÄtgÀrda. I vÀrsta fall Àr skadeförloppet lÄngsamt och visar sig pÄ ytan lÄng tid efter garantibesiktning dÄbestÀllaren sitter ensam med problemet med en anlÀggning som sedan lÀnge tagits i bruk. Det drabbar dÄ i första hand driftsavdelningen och i detta lÀge kommer alla berörda parter att krÀva snabba ÄtgÀrder vilket vanligen medför kosmetiska justeringar pÄ ytan. Eftersom synliga skador i ytan normalt endast Àr ett symptom pÄ ett skadeförlopp vÀl dolt lÀngre ned i överbyggnaden uppnÄr man endast en tillfÀllig förbÀttring, med stÀndigt Äterkommande problem med ytan. Med tiden kommer acceptansnivÄn för ytskadorna att öka och kvar finns dÄ kanske en högbudgetinvestering i lÄgbudgetutförande, med höga driftskostnader som följd

    A Comparison of the Oxidation and Nitridation Properties of Selected Chromia- and Alumina-Forming Alloys at 800 degrees C

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    Three FeCrAl alloys and two chromia-formers (a stainless steel, and a Ni-base alloy) have been exposed in four environments (dry air, air + 20% H2O, 20% H-2 + 20% H2O + Ar and 95% N-2 + 5% H-2) for 168 h at 800 degrees C. The corroded samples were investigated by SEM/EDS, XRD and gravimetry, and the formation of CrO2(OH)(2)(g) was measured as a function of time using a denuder technique. The Fe-base alloy formed a Cr-rich protective oxide scale in dry air and wet air but suffered break-away oxidation in 20% H-2 + 20% H2O + Ar. In contrast, the Ni-base alloy suffered extensive NiO formation and internal oxidation in dry air and wet air but formed a protective chromia scale in 20% H-2 + 20% H2O. All three FeCrAl alloys formed protective alumina scales in dry air, wet air and 20% H-2 + 20% H2O + Ar. The FeCrAl alloy Kanthal APMT was severely nitrided in the 95% N-2 + 5% H-2 environment due to defects in the oxide scale associated with RE-rich inclusions which allowed nitrogen to enter the alloy. In contrast, the two Cr-lean FeCrAl alloys Kanthal EF101 and Kanthal EF100 did not suffer nitridation at all
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