Building Prime Towers to Understand Prime Number​

There has been a fair amount of research over the past several decades on teachers’ understanding of the multiplicative structure of integers. What can easily be discerned from the literature is a lack of understanding on the part of these educational professionals. It would be easy to assume that this lack of understanding is thereby held by the students in these classrooms. Yet, very little research has examined children\u27s understanding of this mathematical idea. In this quasi-experimental study, we focus the effects of the use of a manipulative, the prime towers, in a three-day teaching experiment carried out in a fourth grade classroom. Students “build” towers of blocks that represent each number 2-100 as a product of prime factors. Towers are studied, compared, and contrasted to build understanding of the significance of prime factorization in predicting a number’s multiplicative structure. The experiment measured students’ ability to identify use prime factorization as a tool to find all the factor pairs, multiples, prime, and composite numbers for natural numbers 1-100 (Common Core Standard 4.OA.4). The results demonstrated represent four classes of fourth grade students spanning two schools. The conclusions drawn will help to identify and refine instructional practices that promote the understanding of the Fundamental Theorem of Arithmetic at a fourth grade level. In connection, both qualitative and quantitative data are presented to insure the practices promoted are both instructional and engaging

Fast Time Structure During Transient Microwave Brightenings: Evidence for Nonthermal Processes

Transient microwave brightenings (TMBs) are small-scale energy releases from the periphery of sunspot umbrae, with a flux density two orders of magnitude smaller than that from a typical flare. Gopalswamy et al (1994) first reported the detection of the TMBs and it was pointed out that the radio emission implied a region of very high magnetic field so that the emission mechanism has to be gyroresonance or nonthermal gyrosynchrotron, but not free-free emission. It was not possible to decide between gyroresonance and gyrosynchrotron processes because of the low time resolution (30 s) used in the data analysis. We have since performed a detailed analysis of the Very Large Array data with full time resolution (3.3 s) at two wavelengths (2 and 3.6 cm) and we can now adequately address the question of the emission mechanism of the TMBs. We find that nonthermal processes indeed take place during the TMBs. We present evidence for nonthermal emission in the form of temporal and spatial structure of the TMBs. The fast time structure cannot be explained by a thermodynamic cooling time and therefore requires a nonthermal process. Using the physical parameters obtained from X-ray and radio observations, we determine the magnetic field parameters of the loop and estimate the energy released during the TMBs. The impulsive components of TMBs imply an energy release rate of 1.3 x 10^22 erg/s so that the thermal energy content of the TMBs could be less than 10^24 erg.Comment: 15 pages (Latex), 4 figures (eps). ApJ Letters in press (1997

Early changes in the haemostatic and procoagulant systems after chemotherapy for breast cancer

Venous thromboembolism (VTE) following breast cancer chemotherapy is common. Chemotherapy-induced alterations in markers of haemostasis occur during chemotherapy. It is unclear how rapidly this occurs, whether this is upregulated in patients developing VTE and whether changes predict for VTE. Markers of haemostasis, functional clotting assays and vascular endothelial growth factor were measured before chemotherapy and at 24 h, 4 days, 8 days and 3 months following commencement of chemotherapy in early and advanced breast cancer patients and in age- and sex-matched controls. Duplex ultrasound imaging was performed after 1 month or if symptomatic. Of 123 patients, 9.8% developed VTE within 3 months. Activated partial thromboplastin time (APTT), prothrombin time (PT), D-dimer, fibrinogen, platelet count, VEGF and fibrinogen were increased in cancer. Fibrinogen, D-dimer, VEGF and tissue factor were increased, at baseline, in patients subsequently developing VTE. D-dimer of less than 500 ng ml−1 has a negative predictive value of 97%. Activated partial thromboplastin time, PT and thrombin–antithrombin showed significantly different trends, as early as within 24 h, in response to chemotherapy in patients subsequently developing VTE. Markers of coagulation and procoagulants are increased, before chemotherapy, in patients who subsequently develop VTE. A group of patients at minimal risk of VTE can be identified, allowing targeted thrombopropylaxis to the higher risk group

To which countries do European psychiatric trainees want to move to and why?

publisher: Elsevier articletitle: To which countries do European psychiatric trainees want to move to and why? journaltitle: European Psychiatry articlelink: http://dx.doi.org/10.1016/j.eurpsy.2017.06.010 content_type: article copyright: © 2017 Elsevier Masson SAS. All rights reserved.publisher: Elsevier articletitle: To which countries do European psychiatric trainees want to move to and why? journaltitle: European Psychiatry articlelink: http://dx.doi.org/10.1016/j.eurpsy.2017.06.010 content_type: article copyright: © 2017 Elsevier Masson SAS. All rights reserved.BACKGROUND: There is a shortage of psychiatrists worldwide. Within Europe, psychiatric trainees can move between countries, which increases the problem in some countries and alleviates it in others. However, little is known about the reasons psychiatric trainees move to another country. METHODS: Survey of psychiatric trainees in 33 European countries, exploring how frequently psychiatric trainees have migrated or want to migrate, their reasons to stay and leave the country, and the countries where they come from and where they move to. A 61-item self-report questionnaire was developed, covering questions about their demographics, experiences of short-term mobility (from 3 months up to 1 year), experiences of long-term migration (of more than 1 year) and their attitudes towards migration. RESULTS: A total of 2281 psychiatric trainees in Europe participated in the survey, of which 72.0% have 'ever' considered to move to a different country in their future, 53.5% were considering it 'now', at the time of the survey, and 13.3% had already moved country. For these immigrant trainees, academic was the main reason they gave to move from their country of origin. For all trainees, the overall main reason for which they would leave was financial (34.4%), especially in those with lower (2500€) incomes, personal reasons were paramount (44.5%). CONCLUSIONS: A high number of psychiatric trainees considered moving to another country, and their motivation largely reflects the substantial salary differences. These findings suggest tackling financial conditions and academic opportunities