Representations in matematics education: an onto-semiotic approach

Research in didactics of mathematics has shown the importance that representations have in teaching and learning processes as well as the complexity of factors related to them. Particularly, one of the central open questions that the use of representations poses is the nature and diversity of objects that carry out the role of representation and of the objects represented. The objective of this article is to show how the notion of semiotic function and mathematics ontology elaborated by the ontosemiotic approach of mathematics knowledge, enables us to face such a problem, by generalizing the notion of representation and by integrating different theoretical notions used to describe mathematics cognition

The Challenge of Onboard SAR Processing: A GPU Opportunity

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Pathology and molecular analysis of ' Hapalotrema mistroides ' (Digenea: Spirorchiidae) infecting a Mediterranean loggerhead turtle ' Caretta caretta '

Turtle blood flukes belonging to the family Spirorchiidae (Digenea) represent a major threat for sea turtle health and are considered the most important parasitic cause of turtle stranding and mortality worldwide. Despite the large diversity of spirorchiid species found globally, there are only 2 records for free-ranging Mediterranean sea turtles that date back to the late 1800s involving just Hapalotrema mistroides Monticelli, 1896. This study describes the first fatal confirmed case of spirorchiidiasis in a free-ranging Mediterranean loggerhead turtle Caretta caretta (Linnaeus) and, owing to the complexities of taxonomic identification of these parasites, provides the first molecular characterization and phylogenetic analysis of H. mistroides from the Mediterranean Sea. The loggerhead turtle showed cachexia and digestive disorders associated with severe damage to the pancreas and intestinal ganglia, caused by deposition of Hapalotrema eggs forming granulomas. Massive Hapalotrema egg emboli in several tissues and organs and encephalitis were the most probable contributions to the death of the turtle. The congruence between the phylogenetic analysis of both the ITS2 and 28S rDNA resolved the Italian and USA H. mistroides as the same species, confirming the parasite identification. The case here described clearly indicates that the blood flukes should be considered in the differential diagnosis of Mediterranean sea turtle diseases

Prognostic Factors in Childhood Anaplastic Large Cell Lymphoma: Long Term Results of the International ALCL99 Trial

With the aim of describing the long-term follow-up and to define the prognostic role of the clinical/pathological/molecular characteristics at diagnosis for childhood, adolescent and young adults affected by anaplastic large cell lymphoma (ALCL), we analyzed 420 patients aged up to 22 years homogeneously treated within the international ALCL99 trial. The 10-year progression free survival (PFS) was 70% and overall survival was 90%, rare late relapses occurred but no secondary malignancies were reported. Among clinical/pathological characteristics, only patients presenting a small cell/lymphohistiocytic (SC/LH) pattern were independently associated with risk of failure (hazard ratio = 2.49). Analysis of minimal disseminated disease (MDD), available for 162 patients, showed that both SC/LH pattern (hazard ratio = 2.4) and MDD positivity (hazard ratio = 2.15) were significantly associated with risk of failure in multivariate analysis. Considering MDD and SC/LH results, patients were separated into three biological/pathological (bp) risk groups: a high-risk group (bpHR) including MDD-positive patients with SC/LH pattern; a low-risk group (bpLR) including MDD-negative patients without SC/LH pattern; and an intermediate-risk group (bpIR) including remaining patients. The 10-year PFS was 40%, 75% and 86% for bpHR, bpIR and bpLR, respectively (p 0.0001). These results should be considered in the design of future ALCL trials to tailor individual treatments

Descriptive epidemiology of gastrointestinal non-Hodgkin's lymphoma in a population-based registry

The incidence of non-Hodgkin's lymphoma (NHL), particularly at certain extranodal sites, has been demonstrated to be rising, at least in the USA, more than for any other malignancy. One of the major sites of extranodal NHL is the gastrointestinal tract, though little is known of its epidemiological characteristics. Over an 8-year period (1986 to 1993) 1069 primary gastrointestinal NHL cases were reported to the Leukaemia Research Fund Data Collection Survey which covers many parts of England and Wales. Age-standardized incidence rates of gastrointestinal NHL at all sites (0.58/105 per year), gastric (0.24/105 per year), small bowel (0.17/105 per year) and large bowel (0.06/105 per year) confirmed that the UK has the lowest rates of gastrointestinal NHL in Europe. An excess of males was observed at all ages and for all sites. Time-trend analyses showed annual increases in incidence rates for gastric (6.3%) and small bowel (5.9%) NHL although a concomitant decrease in gastrointestinal NHL of unknown site suggested that at least part of these increases had resulted from more accurate diagnoses. Overall, the incidence of gastrointestinal NHL significantly increased by 2.7% per annum and was limited to the population aged over 50 years in this series. © 1999 Cancer Research Campaig

Association between siesta (daytime sleep), dietary patterns and the presence of metabolic syndrome in elderly living in Mediterranean area (MEDIS study):The moderating effect of gender

Objectives: Several lifestyle parameters including diet, physical activity and sleep were associated in isolation with the presence of Metabolic Syndrome (MetS) in adults, to date there is a paucity of studies which evaluated their combined role aging populations and especially with respect to gender. Therefore, the aim of the present study was to provide a global consideration of the lifestyle factors associated with MetS among elderly individuals. Design: Cross-sectional observational study. Setting: 21 Mediterranean islands and the rural Mani region (Peloponnesus) of Greece. Participants: during 2005-2015, 2749 older (aged 65-100 years) from were voluntarily enrolled in the study. Measurements: Dietary habits, energy intake, physical activity status, sociodemographic characteristics, lifestyle parameters (sleeping and smoking habits) and clinical profile aspects were derived through standard procedures. The presence of MetS was defined using the definition provided by NCEP ATP III (revised) and cluster analysis was used to identify overall dietary habit patterns. Results: The overall prevalence of MetS in the study sample was 36.2%, but occurred more frequently in females (40.0% vs. 31.8%, respectively, p=0.03). Individuals with MetS were more likely to sleep during the day (89.4% vs. 76.8% respectively, p=0.039) and frequent ‘siesta’ was positively linked to the odds of MetS presence in females (Odds Ratio (OR) =3.43, 95% Confidence Intervals (CI): 1.08-10.9), but not for men (p=0.999). The lower carbohydrate (i.e., 45.2% of total daily energy, 120±16gr/day) dietary cluster was inversely associated with the odds for MetS presence, but only for men (OR=0.094, 95%CI: 0.010-0.883). Conclusions: Lifestyle parameters including sleep and diet quality are strongly associated with the presence of MetS in elderly cohort, but different their level of influence appears to be different, depending on gender. Further research is needed to better consider the role of lifestyle characteristics in the management of MetS in clinical practice

The risk of angiosarcoma following primary breast cancer

Lymphangiosarcoma of the upper extremity is a rare and aggressive tumour reported to occur following post-mastectomy lymphoedema (Stewart–Treves syndrome). Haemangiosarcoma, a related rare tumour, has occasionally been reported to occur in the breast following irradiation. We conducted a case-control study using the University of Southern California-Cancer Surveillance Program, the population-based cancer registry for Los Angeles County, to evaluate the relationship between invasive female breast cancer and subsequent upper extremity or chest lymphangiosarcoma and haemangiosarcoma together referred to as angiosarcoma. Cases were females diagnosed between 1972 and 1995 with angiosarcoma of the upper extremity (n = 20) or chest (n = 48) who were 25 years of age or older and residing in Los Angeles County when diagnosed. Other sarcomas at the same anatomic sites were also studied. Controls were females diagnosed with cancers other than sarcoma during the same time period (n = 266 444). Cases and controls were then compared with respect to history of a prior invasive epithelial breast cancer. A history of breast cancer increased the risk of upper extremity angiosarcoma by more than 59-fold (odds ratio [OR] = 59.3, 95% confidence interval [95% CI] = 21.9–152.8). A strong increase in risk after breast cancer was also observed for angiosarcoma of the chest and breast (OR = 11.6, 95% CI = 4.3–26.1) and for other sarcomas of the chest and breast (OR = 3.3, 95% CI = 1.1–1.7). © 1999 Cancer Research Campaig

Micromechanical study of the load transfer in a polycaprolactone-collagen hybrid scaffold when subjected to unconfined and confined compression

Scaffolds are used in diverse tissue engineering applications as hosts for cell proliferation and extracellular matrix formation. One of the most used tissue engineering materials is collagen, which is well known to be a natural biomaterial, also frequently used as cell substrate, given its natural abundance and intrinsic biocompatibility. This study aims to evaluate how the macroscopic biomechanical stimuli applied on a construct made of polycaprolactone scaffold embedded in a collagen substrate translate into microscopic stimuli at the cell level. Eight poro-hyperelastic finite element models of 3D printed hybrid scaffolds from the same batch were created, along with an equivalent model of the idealized geometry of that scaffold. When applying an 8% confined compression at the macroscopic level, local fluid flow of up to 20 [Formula: see text]m/s and octahedral strain levels mostly under 20% were calculated in the collagen substrate. Conversely unconfined compression induced fluid flow of up to 10 [Formula: see text]m/s and octahedral strain from 10 to 35%. No relevant differences were found amongst the scaffold-specific models. Following the mechanoregulation theory based on Prendergast et al. (J Biomech 30:539-548, 1997. https://doi.org/10.1016/S0021-9290(96)00140-6 ), those results suggest that mainly cartilage or fibrous tissue formation would be expected to occur under unconfined or confined compression, respectively. This in silico study helps to quantify the microscopic stimuli that are present within the collagen substrate and that will affect cell response under in vitro bioreactor mechanical stimulation or even after implantation

A tyrosine-rich amelogenin peptide promotes neovasculogenesis in vitro and ex vivo

H.D.A. is grateful for the financial support provided by a Dorothy Hodgkin Postgraduate Award (jointly funded by the Engineering and Physical Sciences Research Council, UK and the Institut Straumann, Switzerland) and the Research Discretionary Funds of the Periodontology Unit, UCL Eastman Dental Institute. Financial support was also provided by the NIHR Comprehensive Biomedical Research Centre, UK and the WCU Program of the National Research Foundation of Korea (NRF), funded by the Ministry of Education, Science and Technology, South Korea (No. R31-10069)