Preservice teachers perception of their preparation program to cultivate their ability to teach proof

This study describes twelve preservice teachers perceptions of their preparation program to foster their ability to teach proof. Data were collected via structured interview questions, relative to participants’ mathematical background, perceptions about proof, and their readiness to teach proof. The study found that most preservice teachers are not afforded many opportunities to prove outside of geometry or bridge to abstract algebra courses, and perceive that they will be challenged to teach proof effectively. The results suggest that the trajectory of preservice mathematics teachers college experience needs to increase opportunities to prove, and practice teaching proof. Furthermore, the findings unveil fundamental misconceptions preservice teachers have about the role and nature of mathematical proof. An analysis of these misconceptions suggests: explanations of the perceptions, and a need to incorporate explicit reflections on the role and nature of proof in teacher education curricula

A statistical study of binary and multiple clusters in the LMC

Based on the Bica et al. (1999) catalogue we studied the star cluster system of the LMC and provide a new catalogue of all binary and multiple cluster candidates found. We performed Monte Carlo simulations and produced artificial cluster distributions that we compared with the real one in order to check how many of the found cluster pairs and groups can be expected statistically due to chance superposition on the plane of the sky. We found that, depending on the cluster density, between 56% (bar region) and 12% (outer LMC) of the detected pairs can be explained statistically. We studied in detail the properties of the multiple cluster candidates. The binary cluster candidates seem to show a tendency to form with components of similar size. When possible, we studied the age structure of the cluster groups and found that the multiple clusters are predominantly young with only a few cluster groups older than 300 Myr. The spatial distribution of the cluster pairs and groups coincides with the distribution of clusters in general; however, old groups or groups with large internal age differences are mainly located in the densely populated bar region. Thus, they can easily be explained as chance superpositions. Our findings show that a formation scenario through tidal capture is not only unlikely due to the low probability of close encounters of star clusters, and thus the even lower probability of tidal capture, but the few groups with large internal age differences can easily be explained with projection effects. We favour a formation scenario as suggested by Fujimoto & Kumai (1997) in which the components of a binary cluster formed together and thus should be coeval or have small age differences compatible with cluster formation time scales.Comment: 19 pages, including 15 figures, accepted for publication in A&A, minor corrections (1 reference removed form the abstract

Measurement of the matter-radiation equality scale using the extended Baryon Oscillation Spectroscopic Survey Quasar Sample

The position of the peak of the matter power spectrum, the so-called turnover scale, is set by the horizon size at the epoch of matter-radiation equality. It can easily be predicted in terms of the physics of the Universe in the relativistic era, and so can be used as a standard ruler, independent of other features present in the matter power spectrum, such as baryon acoustic oscillations (BAO). We use the distribution of quasars measured by the extended Baryon Oscillation Spectroscopic Survey (eBOSS) to determine the turnover scale in a model-independent fashion statistically. We avoid modelling the BAO by down-weighting affected scales in the covariance matrix using the mode deprojection technique. We measure the wavenumber of the peak to be $k_\mathrm{TO} = \left( 17.7^{+1.9}_{-1.7} \right) \times 10^{-3}h/\mathrm{Mpc}$, corresponding to a dilation scale of $D_\mathrm{V}(z_\mathrm{eff} = 1.48) = \left(31.5^{+3.0}_{-3.4}\right)r_\mathrm{H}$. This is not competitive with current BAO distance measures in terms of determining the expansion history but does provide a useful cross-check. We combine this measurement with low-redshift distance measurements from type-Ia supernova data from Pantheon and BAO data from eBOSS to make a sound-horizon free estimate of the Hubble-Lema\^itre parameter and find it to be $H_0=64.8^{+8.4}_{-7.8} \ \mathrm{km/s/Mpc}$with Pantheon, and$H_0=63.3^{+8.2}_{-6.9} \ \mathrm{km/s/Mpc}$ with eBOSS BAO. We make predictions for the measurement of the turnover scale by the Dark Energy Spectroscopic Instrument (DESI) survey, the Maunakea Spectroscopic Explorer (MSE) and MegaMapper, which will make more precise and accurate distance determinations.Comment: 11 pages, 9 figure

Functioning and health in patients with cancer on home-parenteral nutrition: a qualitative study

<p>Abstract</p> <p>Background</p> <p>Malnutrition is a common problem in patients with cancer. One possible strategy to prevent malnutrition and further deterioration is to administer home-parenteral nutrition (HPN). While the effect on survival is still not clear, HPN presumably improves functioning and quality of life. Thus, patients' experiences concerning functioning and quality of life need to be considered when deciding on the provision of HPN. Currently used quality of life measures hardly reflect patients' perspectives and experiences. The objective of our study was to investigate the perspectives of patients with cancer on their experience of functioning and health in relation to HPN in order to get an item pool to develop a comprehensive measure to assess the impact of HPN in this population.</p> <p>Methods</p> <p>We conducted a series of qualitative semi-structured interviews. The interviews were analysed to identify categories of the International Classification of Functioning, Disability and Health (ICF) addressed by patients' statements. Patients were consecutively included in the study until an additional patient did not yield any new information.</p> <p>Results</p> <p>We extracted 94 different ICF-categories from 16 interviews representing patient-relevant aspects of functioning and health (32 categories from the ICF component 'Body Functions', 10 from 'Body Structures', 32 from 'Activities & Participation', 18 from 'Environmental Factors'). About 8% of the concepts derived from the interviews could not be linked to specific ICF categories because they were either too general, disease-specific or pertained to 'Personal Factors'. Patients referred to 22 different aspects of functioning improving due to HPN; mainly activities of daily living, mobility, sleep and emotional functions.</p> <p>Conclusions</p> <p>The ICF proved to be a satisfactory framework to standardize the response of patients with cancer on HPN. For most aspects reported by the patients, a matching concept and ICF category could be found. The development of categories of the component 'Personal Factors' should be promoted to close the existing gap when analyzing interviews using the ICF. The identification and standardization of concepts derived from individual interviews was the first step towards creating new measures based on patients' preferences and experiences which both catch the most relevant aspects of functioning and are sensitive enough to monitor change associated to an intervention such as HPN in a vulnerable population with cancer.</p

A poverty profile for rural Botswana

Recognizing that for policy purposes it is important to learn in what ways households that are poor differ from households that have a more adequate income and recognizing that these differences may be cause or consequence of low economic status, this paper compiles a `poverty profile' of rural Botswana. The data are taken from the Rural Income Distribution Survey conducted in 1975 by the Central Statistical Office of the Government of Botswana - a sample of 950 randomly selected households in 20 rural areas. The survey data enable the authors to determine how close each household comes to meeting its basic requirements.The paper begins by explaining the derivation of `poverty income ratios'; it then relates the PIRs to the demographic characteristics of households, their education, location and asset holdings. There follows a description of differences in time use and sources of income among the five poverty ratio groups. The authors conclude with a discussion of the implications for policies aimed at the alleviation of poverty.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/24921/1/0000348.pd