217 research outputs found
Analyzing difficulties in arithmetic word problem solving: An epistemological case study in primary school
No full textThis paper focuses on difficulties that primary school students have in facing mathematical word problems. In particular, we are interested in exploring how they develop in the transition from grade 2 to grade 5. The research basis of the hypothesis is that some difficulties detected in grade 5 are already predictable in grade 2. Starting from the data collected in grade 5 by the National Standardized Assessment, we carry out a quantitative analysis looking for word problems in which students experience difficulties. Subsequently, we conduct a backward analysis of the grade 2 test of the same cohort of students in order to identify a set of word problems linked with those selected in grade 5 test. The analysis shows the presence of many common difficulties in the two grades. We design and carry out specific educational activities concerning word problem-solving in grade 2. These activities produce positive changes in the experimental class compared to the control class. This could suggest that a previous intervention in grade 2 could allow overcoming future difficulties in word problem text comprehension in grade 5
Multiscale relaxation in aging colloidal gels: From localized plastic events to system-spanning quakes
No full textRelaxation of internal stresses through a cascade of microscopic restructuring events is the hallmark of many materials, ranging from amorphous solids like glasses and gels to geological structures subjected to a persistent external load. By means of photon correlation imaging, a recently developed technique that blends the powers of scattering and imaging, we provide a spatially and temporally resolved survey of the restructuring and aging processes that spontaneously occur in physical gels originating from an arrested phase separation. We show that the temporal dynamics is characterized by an intermittent sequence of spatially localized "microquakes" that eventually lead to global rearrangements occurring at a rate that scales with the gel age. Notably, these dramatic upheavals of the gel structure are heralded by a progressive acceleration of the microscopic gel dynamics that originates from recognizable active spots and then spreads at a large but finite speed through the gel. Within the "slack" phase between two of these "macroquakes," the fluctuations of the degree of temporal correlation obey a non-Gaussian statistics described by a generalized logistic distribution. The evidence we obtained bear consistent analogies with the stress relaxation processes taking place in earthquake sequences and with the intermittent restructuring of plastic crystals at the microscale
Personalized surgery for rectal tumours : the patient's opinion counts
No full textIn recent times there have been many important changes in the surgical management of rectal cancer. The general thrust of these changes has been towards a less invasive approach with preservation of intestinal continuity and avoidance of the psychological se quelae of a stoma, It is also becomming increasingly apparent that profound sexual and autonomic dysfunction can be associated with abdominoperineal resection. This paper highlights these issues and the conflict between performing an adequate oncological proceedure and reducing the incidence of postoperative psychological morbidity, It outlines the great changes there have been in surgical technique and their relevance to psychological problems after surgery for rectal cancer, The need for auditing psychological morbidity when assessing the outcome of surgical series is emphasised, as is the importance of involving the patient in the medical decision making
Studio di mortalità fra i lavoratori di una conceria
No full textmortalità fra i lavoratori di una conceri
The application of different correlation coefficients to assess the reproducibility of a food frequency questionnaire
No full textWe computed four different correlation coefficients to investigate the degree of reproducibility of the weekly consumption of 77 food items or groups of foods and of seven summary questions from a food frequency questionnaire developed in Italy for a case-control study on cancers of the breast and digestive tract. The questionnaire had been administered twice to 452 Italian men and women. These included Pearson correlation coefficients (a) using the weekly frequencies of consumption without any transformation (P1); (b) after applying the transformation log (x + 1) (P2); (c) after applying the transformation log (x + 0.01) (P3); and (d) the Spearman correlation coefficient (SP). The mean values were 0.55 for P1, 0.59 for P2, 0.56 for P3 and 0.59 for SP. All coefficients were positively correlated, although to variable extents: the Spearman correlation coefficient between P2 and SP was 0.92, and that between P1 and P3 was 0.53. Differences between the four coefficients were more marked for food items with a lower kappa statistic and lower intraclass correlation, ie for those items with more severe reproducibility problems. Thus, a single correlation coefficient may not be enough to detect zones of the distribution of a food item where misclassification problems are more severe. The correlation coefficients used to investigate reproducibility should therefore be chosen on the basis of subsequent data analyses
Evaluation of a series of serum mesothelin in patients with pleural Malignant Mesothelioma
No full textPleural Malignant Mesothelioma (MM) is a highly aggresive neoplasm with a poor survival rate, hard diagnosis and treatment. The incidence of MM in Western Europe countries is expected to increase drammatically in the next 10-15 years. In spite of this drammatic scenario, at this time the only instruments for screening and early diagnosis are based on radiological tests with evident ethical and economical problems. For this reason, some authors are evaluating biological indicators with the significance of screening and early diagnosis markers. One of the most promising marker is serum mesothelin (SMRP). SMRP levels appeares to be significantly related to MM and its clinical (diagnostic/prognostic) usefulnes has been suggested. The purpouse of this research is to show SMRP trend in relation both to the course of the disease and the response to therapies in some Epithelioid MM patients. The analysis of SMRP levels in these patients suggests that it may be a useful marker for monitoring the response to treatment. In fact, it was observed that SMRP increases in patients who did not respond to therapy, it tends to remain stable when therapies results into a clinical stabilization, while it decreases after surgical procedure and in case of clinical improvement
Sul controllo di qualità dei distaccanti, ausiliari per prodotti da forno
No full textGli Autori evidenziano l’importanza dell’attività del controllo qualità nella produzione degli agenti distaccanti da impiegare nell’industria dei prodotti da forno. A questo proposito risulta importante la verifica di qualità della frazione grassa utilizzata come componente fondamentale e veicolante altre materie prime e/o additivi, e vengono riportati dati di composizione in trigliceridi di oli impiegati in formulazione di alcuni distaccanti in commercio sul mercato nazionale.
Nello stesso tempo si dimostra evidente il fenomeno di migrazione del distaccante dal contenitore di
cottura al prodotto da forno cotto: ciò suggerisce considerazioni utili in merito all’uso di alcuni componenti ausiliari impiegati in formulazione. Con tale nota si auspica una più chiara regolamentazione dell’uso di alcuni additivi oltre ad una sempre maggiore attenzione per la razionale scelta delle materie prime impiegate, sia ai fini della costanza di efficienza che ai fini della qualità e sicurezza degli alimenti
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