Changes in School Mathematics: Curricular Changes, Instructional Changes and Indicators of Change

Discusses how the mathematics curriculum should be changed to reflect changes in the nation’s economic and social culture brought on by new technology. The report also outlines the National Council of Teachers of Mathematics (NCTM) proposal for new curriculum and evaluation standard

What are the aims of research in mathematics education?

This group was asked to consider at length possible answers to the question of aims in order to clarify the notion of research in mathematics education as an academic activity. In particular, the group was asked to examine 'two kinds of aims: pragmatic aims and more fundamental scientific aims'

Perspectivas sobre o Conhecimento e Métodos de Pesquisa

The interest of scholars in Mathematical Education about problems associated with the teaching and learning of mathematics has been strongly expressed and discussed, during the past quarter century, in carrying out their investigations. Romberg, in this article, intends to identify in the social sciences the broad research trends that are related to the study of teaching and learning in school settings and to determine how those trends have influenced thestudy of mathematics in schools. As an aid for understanding the basis of these trends, the author begins by describing some features of mathematical education as a field of study. He then sketches the activities of researchers and outlines the variety of research methods now in use. Finally, he presents five general research trends and their relationship to studies in mathematical education, which are identified and briefly described. Key words: Mathematical Education; Research Methods, Activities of Researchers; Research Trends in Mathematical Education.O interesse de estudiosos na área de Educação Matemática em problemas relacionados ao ensino e à aprendizagem de matemática tem sido fortemente manifestado e discutido no último quarto do século XX, constituindo-se em um espaço de investigação. Romberg, nesse artigo, procura identificar nas ciências sociais as amplas tendências de pesquisa relacionadas ao estudo do ensino e da aprendizagem em ambientes escolares e determinar como estas tendências têm influenciado o estudo da matemática nas escolas. Na tentativa de entender a base destas tendências, o autor descreve, inicialmente, algumas características da educação matemática como um campo de estudo. A seguir, esboça as atividades dos pesquisadores e resume a variedade de métodos de pesquisa utilizados atualmente. Por fim, apresenta cinco tendências de pesquisa gerais e suas relações com estudos em educação matemática, identificando-as e descrevendo-as brevemente. Palavras-chave: Educação Matemática; Métodos de Pesquisa, Atividades de Pesquisadores; Tendências de Pesquisa em Educação Matemática

Beiträge in den Jahren 1972-1973

Dieses Mitteilungsheft enthält unsere seit der Herausgabe des ersten Sammelbandes (Heft 7) entstandenen Beiträge. Einige der Beiträge sind bei der Bearbeitung von Fragen aus der Praxis entstanden. Sie stehen daher in keinem unmittelbaren Zusammenhang. Hingegen haben wir vor einigen Jahren mit Untersuchungen über die Spannungs-Dehnungsbeziehungen der Böden begonnen. Hierzu gehören auch die Setzungsmessungen an Hochhäusern und die Verschiebungsmessungen an Baugrubenwänden in der Frankfurter Innenstadt. Sie sollten über das Verformungsverhalten des dortigen Tons Aufschluß geben. Desweiteren haben wir mit Versuchen über die "Stress strain characteristics of sands" begonnen, über deren bisherige Ergebnisse im August dieses Jahres ein Bericht im Journal of the Soil Mechanics and Foundations Division, Proceedings of the American Society of Civil Engineers, Vol. 99, No. SM8, p. 617-632 erschienen ist. Nachdem die Erforschung der Spannungs-Dehnungsbeziehung der Böden von der Deutschen Forschungsgemeinschaft mit der Bildung eines Schwerpunktes eine bevorzugte Förderung erfahren hat, konnten Untersuchungen verstärkt weitergeführt werden. Mit einer verbesserten Meßtechnik werden die Versuche über die Verformungseigenschaften des Sandes fortgesetzt und der Einfluß der Vorbelastung und der Seitenspannung auf sein Verformungsverhalten geprüft. In Verbindung mit diesen Versuchen werden Setzungsmessungen unter einem auf Sand gegründeten über 100.000 Mp schweren Reaktorgebäude ausgeführt. Von einer Arbeitsgruppe wurde ein FEM-Programm für die Anwendung im Erd- und Grundbau entwickelt, daß auch nichtlineare Verformungsvorgänge im Boden nachvollzogen werden können. Mit Hilfe dieses Programms ist es gelungen, die in Frankfurt gemessenen Hochhaussetzungen und Wandverschiebungen mit den an Proben festgestellten Spannungs-Dehnungsbeziehungen des Frankfurter Tons in Einklang zu bringen und damit einen Einblick in die Verformungsvorgänge unter Bauwerken und im Umkreis von tiefen Baugruben zu gewinnen. Über diese Arbeiten werden wir in den nächsten Mitteilungen berichten

Preoperative screening and prehabilitation strategies prior to ileocolic resection in patients with Crohn’s disease are not incorporated in routine care

Purpose: Recently, recommendations on perioperative care have been published to optimize postoperative outcomes in preoperative patients with inflammatory bowel disease. This study evaluated the current use of preoperative screening and prehabilitation strategies (PS) prior to elective ileocolic resection (ICR) in patients with Crohn’s disease (CD). Methods: Patients with CD who underwent an elective ICR were identified from a Dutch prospective cohort study. Primary endpoint was to evaluate to what extent IBD-relevant PS were applied in patients with CD prior to ICR according to the current recommendations. Results: In total, 109 CD patients were included. Screening of nutritional status was performed in 56% of the patients and revealed malnutrition in 46% of these patients. Of the malnourished patients, 46% was referred to a dietitian. Active smoking and alcohol consumption were reported in 20% and 28%; none of these patients were referred for a cessation program. A preoperative anemia was diagnosed in 61%, and ferritin levels were assessed in 26% of these patients. Iron therapy was started in 25% of the patients with an iron deficiency anemia. Exposure to corticosteroids at time of ICR was reported in 29% and weaned off in 3%. Consultation of a dietitian, psychologist, and physiotherapist was reported in 36%, 7%, and 3%. Physical fitness was assessed in none of the patients. Conclusion: PS are not routinely applied and not individually tailored in the preoperative setting prior to elective ICR in patients with CD. Prior to implementation, future research on the costs and effectiveness of PS on postoperative outcomes and quality of life is necessary.</p

Current evidence for a modulation of low back pain by human genetic variants

The manifestation of chronic back pain depends on structural, psychosocial, occupational and genetic influences. Heritability estimates for back pain range from 30% to 45%. Genetic influences are caused by genes affecting intervertebral disc degeneration or the immune response and genes involved in pain perception, signalling and psychological processing. This inter-individual variability which is partly due to genetic differences would require an individualized pain management to prevent the transition from acute to chronic back pain or improve the outcome. The genetic profile may help to define patients at high risk for chronic pain. We summarize genetic factors that (i) impact on intervertebral disc stability, namely Collagen IX, COL9A3, COL11A1, COL11A2, COL1A1, aggrecan (AGAN), cartilage intermediate layer protein, vitamin D receptor, metalloproteinsase-3 (MMP3), MMP9, and thrombospondin-2, (ii) modify inflammation, namely interleukin-1 (IL-1) locus genes and IL-6 and (iii) and pain signalling namely guanine triphosphate (GTP) cyclohydrolase 1, catechol-O-methyltransferase, μ opioid receptor (OPMR1), melanocortin 1 receptor (MC1R), transient receptor potential channel A1 and fatty acid amide hydrolase and analgesic drug metabolism (cytochrome P450 [CYP]2D6, CYP2C9)

Identification of germline monoallelic mutations in IKZF2 in patients with immune dysregulation

Helios, encoded by IKZF2, is a member of the Ikaros family of transcription factors with pivotal roles in T-follicular helper, NK- and T-regulatory cell physiology. Somatic IKZF2 mutations are frequently found in lymphoid malignancies. Although germline mutations in IKZF1 and IKZF3 encoding Ikaros and Aiolos have recently been identified in patients with phenotypically similar immunodeficiency syndromes, the effect of germline mutations in IKZF2 on human hematopoiesis and immunity remains enigmatic. We identified germline IKZF2 mutations (one nonsense (p.R291X)- and 4 distinct missense variants) in six patients with systemic lupus erythematosus, immune thrombocytopenia or EBV-associated hemophagocytic lymphohistiocytosis. Patients exhibited hypogammaglobulinemia, decreased number of T-follicular helper and NK cells. Single-cell RNA sequencing of PBMCs from the patient carrying the R291X variant revealed upregulation of proinflammatory genes associated with T-cell receptor activation and T-cell exhaustion. Functional assays revealed the inability of HeliosR291X to homodimerize and bind target DNA as dimers. Moreover, proteomic analysis by proximity-dependent Biotin Identification revealed aberrant interaction of 3/5 Helios mutants with core components of the NuRD complex conveying HELIOS-mediated epigenetic and transcriptional dysregulation.Peer reviewe

Disentangling Immediate Adaptive Introgression from Selection on Standing Introgressed Variation in Humans.

Recent studies have reported evidence suggesting that portions of contemporary human genomes introgressed from archaic hominin populations went to high frequencies due to positive selection. However, no study to date has specifically addressed the postintrogression population dynamics of these putative cases of adaptive introgression. Here, for the first time, we specifically define cases of immediate adaptive introgression (iAI) in which archaic haplotypes rose to high frequencies in humans as a result of a selective sweep that occurred shortly after the introgression event. We define these cases as distinct from instances of selection on standing introgressed variation (SI), in which an introgressed haplotype initially segregated neutrally and subsequently underwent positive selection. Using a geographically diverse data set, we report novel cases of selection on introgressed variation in living humans and shortlist among these cases those whose selective sweeps are more consistent with having been the product of iAI rather than SI. Many of these novel inferred iAI haplotypes have potential biological relevance, including three that contain immune-related genes in West Siberians, South Asians, and West Eurasians. Overall, our results suggest that iAI may not represent the full picture of positive selection on archaically introgressed haplotypes in humans and that more work needs to be done to analyze the role of SI in the archaic introgression landscape of living humans

Stealth monoolein-based nanocarriers for delivery of siRNA to cancer cells

While the delivery of small interfering RNAs (siRNAs) is an attractive strategy to treat several clinical con- ditions, siRNA-nanocarriers stability after intravenous administration is still a major obstacle for the development of RNA-interference based therapies. But, although the need for stability is well recognized, the notion that strong stabilization can decrease nanocarriers efficiency is sometimes neglected. In this work we evaluated two stealth functionalization strategies to stabilize the previously validated dioctade- cyldimethylammonium bromide (DODAB):monoolein (MO) siRNA-lipoplexes. The nanocarriers were pre- and post-pegylated, forming vectors with different stabilities in biological fluids. The stealth nanocarriers behavior was tested under biological mimetic conditions, as the production of stable siRNA-lipoplexes is determinant to achieve efficient intravenous siRNA delivery to cancer cells. Upon incubation in human serum for 2 h, by fluorescence Single Particle Tracking microscopy, PEG-coated lipo- plexes were found to have better colloidal stability as they could maintain a relatively stable size. In addi- tion, using fluorescence fluctuation spectroscopy, post-pegylation also proved to avoid siRNA dissociation from the nanocarriers in human serum. Concomitantly it was found that PEG-coated lipoplexes improved cellular uptake and transfection efficiency in H1299 cells, and had the ability to silence BCR-ABL, affecting the survival of K562 cells. Based on an efficient cellular internalization, good silencing effect, good siRNA retention and good col- loidal stability in human serum, DODAB:MO (2:1) siRNA-lipoplexes coated with PEG-Cer are considered promising nanocarriers for further in vivo validation. Statement of Significance This work describes two stealth functionalization strategies for the stabilization of the previously validated dioctadecyldimethylammonium bromide (DODAB):monoolein (MO) siRNA-lipoplexes. These nanocarriers are capable of efficiently incorporating and delivering siRNA molecules to cells in order to silence genes whose expression is implicated in a pathological condition. The main objective was to functionalize these nanocarriers with a coating conferring protection to siRNA in blood without compromising its efficient delivery to cancer cells, validating the potential of DODAB:MO (2:1) siRNA-lipoplexes as therapeutic vec- tors. We show that the stealth strategy is determinant to achieve a stable and efficient nanocarrier, and that DODAB:MO mixtures have a very promising potential for systemic siRNA delivery to leukemic cells.FEDER through POFC-COMPETE and by national funds from FCT I.P. through the strategic funding UID/BIA/04050/2013 (CBMA) and PEst-C/FIS/UI0607/2013 (CFUM) and PTDC/QUI/69795/2006. We thank the support of the Frame Work Program 7 of the European Commission: BIOCAPS (316265, FP7/REGPOT) and Xunta de Galicia, Spain (Agrupamento INBIOMED, Grupo con potencial crecimiento) reference IF/00498/2012, scholarship SFRH/BD/68588/2010. NanoDelivery-I&D em Bionanotecnologia, Lda. for access to their equipment