Una visión actualizada de la didáctica de la matemática en educación infantil = An up-to-date vision of pre-school mathematics teaching

This article aims to investigate pre-school mathematics teaching from an uptodate perspective. To pursue this contemporary vision we focus on four key questions: what kind of maths is being worked on, who is doing it, how it is being done, and why it is being done

The pre-history of cryoscopy: what was done before raoult?

Cryoscopy is considered one of the foundations of the modern theory of solutions and of physical chemistry. This paper shows in order the first regularities pointed out by several scientists on the subject, in the first chapter of its birth as a scientific discipline. The study is focused on the identification of the different steps that helped, first qualitatively and then quantitatively, to adjust the different classes of possible solutions, including those that formed hydrates, to a basic formulation that the French scientist François-Marie Raoult would later generalize in the law that bears his name.

The importance of pre-treatment of spent hydrotreating catalysts on metals recovery

This work describes a three-step pre-treatment route for processing spent commercial NiMo/Al2O3 catalysts. Extraction of soluble coke with n-hexane and/or leaching of foulant elements with oxalic acid were performed before burning insoluble coke under air. Oxidized catalysts were leached with 9 mol L-1 sulfuric acid. Iron was the only foulant element partially leached by oxalic acid. The amount of insoluble matter in sulfuric acid was drastically reduced when iron and/or soluble coke were previously removed. Losses of active phase metals (Ni, Mo) during leaching with oxalic acid were compensated by the increase of their recovery in the sulfuric acid leachate.

Bioanalytical method for the quantification of the monastrol derivative anticancer candidate lasom 65 in pre-clinical pharmacokinetic investigations

A simple HPLC/UV method was developed for the determination of the anticancer candidate LaSOM 65 in rat plasma. Samples were cleaned by protein precipitation with acetonitrile (recovery > 95%), after which they were subjected to chromatography under the isocratic elution of an acetonitrile:water (45:55, ν/ν) solution with detection at 303 nm. The method was linear (r² > 0.98) over the concentration range (0.05-2 µg mL-1) with intra- and inter-day precision ranging from 9.6% to 13.6% and 4.3% to 5.4%, respectively. The accuracy of the method ranged from 85% to 113.6%, and it showed sufficient sensitivity to determine pharmacokinetic parameters of LaSOM 65 after intravenous administration to Wistar rats.

Considerações gerais em tôrno da região lagunar de Cananéia: Iguape. II - Diversos aspétos atuais da região lagunar

O trabalho em questão teve como principal objetivo servir de nota introdutória à pesquisa que se processa no setor Iguape-Cananéia, situado no litoral sul do E. de S. Paulo. Pareceu ao autor providência inadiável efetuar tal investigação, em virtude do caráter muito especial do sistema lagunar, considerado, por assim dizer, como chave indispensável ao entendimento do que se passa no conjunto da região. Inicialmente, procurou o autor apresentar um ensaio hipotético da gênese da região. A primeira parte desse estudo figura no número 1 deste Boletim e compreende o exame da questão, partindo da pre-existência de um golfo pintalgado de ilhas montanhosas e do seu entupimento em consequência do carreteamento de produtos terrígenos decorrentes de erosões. Seguem-se a atuação dos ventos dominantes e das correntes de maré, o papel retentor desempenhado pela vegetação dos mangues e a esquematização do processo, em quatro fases diferentes e que justificam as modificações hipotéticas aventadas. Na segunda parte, trata o autor da descrição dos diversos aspectos da região lagunar, dividida em zonas naturais, como segue: la. Canal principal: 2.º Mar do Cubarão; 3.º Baía do Trapandé e suas dependências; 4.º "marigots"; 5.º canal do Ribeira de Iguapé e 6.º canal e Mar do Ararapira. Conquanto se trate de trabalho particularmente mais aprofundado na parte relativa à geografia física, nele se situam pesquisas oceanográficas, hidrológicas, botânicas, físicas, químicas e de zoologia geral, decorrentes da necessidade premente de se conhecer um grande centro produtor de fitoplancton representado, sobretudo, por Diatomáceas.

Determination of Copper, Iron, Nickel and Zinc in fuel kerosene by FAAS after adsorption and pre-concentration on 2-aminothiazole-modified silica gel

Silica gel chemically modified with 2-Aminotiazole groups, abbreviated as SiAT, was used for preconcentration of copper, zinc, nickel and iron from kerosene, normally used as a engine fuel for airplanes. Surface characteristics and surface area of the silica gel were obtained before and after chemical modification using FT-IR, Kjeldhal and surface area analysis (B.E.T.). The retention and recovery of the analyte elements were studied by applying batch and column techniques. The experimental parameters, such as shaking time in batch technique, flow rate and concentration of the eluent (HCl- 0.25-2.00 mol L-1) and the amount of silica, on retention and elution, have been investigated. Detection limits of the method for copper, iron, nickel and zinc are 0.77, 2.92, 1.73 and 0.097 mg L-1, respectively. The sorption-desorption of the studied metal ions made possible the development of a preconcentration method for metal ions at trace level in kerosene using flame AAS for their quantification.

Imaging of Dopamine and Serotonin Transporters. Pre-clinical Studies with Radiotracers for Positron Emission Tomography

The action of the neurotransmitters dopamine (DA) and serotonin (5-HT) at synapses is terminated by their rapid reuptake into presynaptic nerve endings via plasma membrane dopamine (DAT) and serotonin (SERT) transporters. Alterations in the function of these transporters have been suggested as a feature of several neurological and neuropsychiatric diseases, such as Parkinson’s disease (PD), depression, and anxiety. A suitable clinical method for studying these transporters non-invasively in vivo is positron emission tomography (PET) utilizing radiopharmaceuticals (tracers) labelled with short-lived positron-emitting radionuclides. The aim of this study was to evaluate in rats two novel radiotracers, [¹⁸F]beta -CFT-FP and ¹⁸FFMe-McN, for imaging DAT and SERT, respectively, using in vitro, ex vivo and in vivo methods. Substituting an N-methyl in [¹⁸F]beta-CFT, a well known DAT tracer, with a ¹⁸Ffluoropropyl group significantly changed the properties of the tracer. [¹⁸F]beta- CFT showed slow kinetics and metabolism, and a high specific uptake in the striatum, whereas [¹⁸F]beta-CFT-FP showed fast kinetics and metabolism, and a moderate specific uptake in the striatum. [¹⁸F]betaCFT-FP was selective for DAT; but [¹⁸F]beta-CFT also bound to the noradrenaline transporter. [¹⁸F]beta-CFT-FP may be a suitable PET tracer for imaging the striatal DAT sites, but a tracer with a higher affinity is needed for imaging extrastriatal DAT sites. In rats, ¹⁸FFMe-McN showed high target-to-non-target ratios, specificity and selectivity for SERT, but slow kinetics. However, ¹⁸FFMe-McN reveals potential for imaging SERT, at least in pre-clinical studies. In addition, the sensitivities of [¹⁸F]beta CFT and [¹⁸ F]FDOPA (a precursor of DA) for detecting mild nigrostriatal hypofunction were compared in an animal model of PD. The uptake of [¹⁸F]FDOPA was significantly affected by compensatory effects in dopaminergic cells, whereas [¹⁸F]beta-CFT was more sensitive and therefore more suitable for PET studies of mild dopaminergic symptoms. In conclusion, both novel tracers, [¹⁸F]-CFT-FP and ¹⁸FFMe-McN, have potential, but are not optimal PET tracers for DAT and SERT imaging in rats, respectively. [¹⁸F]beta-CFT is superior to [18F]FDOPA for imaging mild nigral lesions in rat brains.

”Hollywood-syndromi”, jazzia ja dodekafoniaa : elokuvamusiikin funktioanalyysi neljässä 1950- ja 1960-luvun vaihteen suomalaisessa elokuvassa

Musiken som hördes i de finländska filmerna vid skiftet av 1950- och 1960-talet var mycket varierande. Det fanns till exempel jazzschlager, modern konstmusik som innovativt kombinerats med Hollywood-klichéer, dodekafonisk musik och mainstream jazz. Gällande stilval, kompositionssätt, instrumentering, harmonisering och användningssätt av filmmusik rådde det då möjligen en större frihet än någonsin i Finland. Anu Juvas avhandling behandlar musiken till fyra filmer genom filmmusikens funktionsanalys och i sitt kulturhistoriska sammanhang. Näranalyserna har gjorts av Lasisydän ( Glashjärtat 1959) och Komisario Palmun erehdys ( Mysteriet Rygseck [sic!] 1960), som Matti Kassila har regisserat, Maunu Kurkvaaras Yksityisalue ( Privatområde 1962) och Erkko Kivikoskis Kesällä kello 5 ( Klockan 5 denna sommar 1963). Musiken till dessa filmer har komponerats av Jaakko Salo, Osmo Lindeman, Usko Meriläinen och Pentti Lasanen. Regissörerna och kompositörerna till dessa filmer var alla på olika sätt förnyare av sin tids konventioner. Funktionsanalysen avslöjar, hur musiken i filmerna fungerar, dvs. vilka dess uppgifter är i dessa filmer som låter mycket olika. Vidare granskas det, hur musik valdes till olika filmer samt de olika genrernas ställning inom det kulturella fältet. Undersökningen öppnar en utsikt över en av de mest intressanta tidpunkterna inom finländsk filmmusik.

Seriedebatt i 1950-talets Finland : en studie i barndom, media och reglering

I avhandlingen granskas den debatt som fördes om seriemediet och serieläsandet i Finland från början av 1950-talet till början av 1960-talet. Serietidningen var då ett nytt medium och föranledde en oro beträffande barns läsvanor. ”Seriefrågan” diskuterades i pressen och problematiken engagerade barnskyddsorganisationer och forskare, behandlades i riksdagen och undersöktes av en statlig kommitté. De olika debattuttrycken analyseras i studien. Avhandlingens teoretiska perspektiv är styrningsanalytiskt och bygger på diskussionen om regementalitet (governmentality). I studien granskas hur seriemediet, barndom och regleringen av dessa kom att definieras i behandlingen av det s.k. serieproblemet. Serierna definierades som ett problematiskt medium på ett flertal sätt. De huvudsakliga argumenten mot serierna var dels att de förstörde barns läsförmåga, dels att de budskap som serierna förmedlade till barnen var av fel slag. Enligt kritiken var serierna språkligt fattiga och innehållsmässigt alltför våldsamma. Följaktligen utgjorde serierna ett hot mot barnen. Barnen kom ur detta perspektiv att definieras som inkompetenta medieanvändare och i behov av skydd. I debatten upplyftes olika sätt att lösa och reglera problemet. Man undersökte problematiken och upplyste allmänheten om den, man försökte påverka serieutgivarna och man påkallade censur. Seriedebatten och den verksamhet som debattörerna ägnade sig åt ledde dock inte till synbara resultat, t.ex. ny lagstiftning eller förändringar i seriemarknaden. Ändå dog debatten i början av 1960-talet. Problemet med de serieläsande barnen hanterades m.a.o. genom själva debatten. Samtidigt uteblev mera drastiska former av reglering. Ett övergripande syfte för analysen av den kunskap som skapades i debatten – dess varierande förståelse av seriemedium, barndom och reglering – är att erbjuda infallsvinklar till aktuella diskussioner om och farhågor angående barns mediebruk. Med fokus på bredden hos debattens uttryck och de diskursiva ramarna för problematiseringen av barns serieläsande ger avhandlingen perspektiv på den med jämna mellanrum uppdykande frågeställningen om barns mediebruk.