Monitoring Student Cues: Tracking Student Behaviour in Order to Improve Instruction in Higher Education

In this paper, we focus on monitoring, a particular aspect of reflection related to teaching. We define monitoring as a feedback mechanism which entails attending to and evaluating a multitude of cues in the envi- ronment in order to evaluate progress towards a goal. We direct our attention to monitoring because it is a way in which a teacher is able to gain understanding of how effective his/her teaching actions are. Thus, knowing what cues to evaluate (and being able to do so) is a critical skill in reflection. Further, we focus exclusively in this paper on the concur- rent monitoring of cues related to students since we believe that attention to student cues while teaching provides teachers with a window into their students' learning experiences. We call this particular type of reflection, reflection-in-action. As well as depicting multiple examples of monitoring drawn from our research, we explore the contribution of this work to the literature in higher education and to faculty development activities, particularly, to the growing literature on teacher thinking.Cet article est principalement consacré au «monitorage», c'est-à-dire à un aspect particulier de la réflexion portant sur l'enseignement. Nous entendons par monitorage un mécanisme de rétroaction qui consiste à observer et à évaluer une multitude de signaux dans un environnement donné afin de mesurer les progrès accomplis par rapport à un objectif. Nous nous intéressons au monitorage, car ce moyen permet au professeur de mesurer l'efficacité de ses interventions. Pour mener à bien cette réflexion, il est donc essentiel de pouvoir déterminer quels signaux il faut évaluer (et d'être en mesure de les évaluer). Cet article porte en outre exclusivement sur le monitorage simultané des signaux émis par les étudiants, car nous pensons que l'observation de ces signaux fournit au professeur un aperçu des apprentissages que font les étudiants. Nous appelons "réflexion sur le vif' ce type de réflexion. En plus d'offrir de nombreux exemples de monitorage tirés de nos recherches, nous étudions sous tous ses aspects la contribution qu'elles apportent aux études consacrées à l'enseignement supérieur et au perfectionnement des professeurs et particulièrement aux études de plus en plus nombreuses qui portent sur la pensée des professeurs

A Comprehensive Spectroscopic Analysis of DB White Dwarfs

We present a detailed analysis of 108 helium-line (DB) white dwarfs based on model atmosphere fits to high signal-to-noise optical spectroscopy. We derive a mean mass of 0.67 Mo for our sample, with a dispersion of only 0.09 Mo. White dwarfs also showing hydrogen lines, the DBA stars, comprise 44% of our sample, and their mass distribution appears similar to that of DB stars. As in our previous investigation, we find no evidence for the existence of low-mass (M < 0.5 Mo) DB white dwarfs. We derive a luminosity function based on a subset of DB white dwarfs identified in the Palomar-Green survey. We show that 20% of all white dwarfs in the temperature range of interest are DB stars, although the fraction drops to half this value above Teff ~ 20,000 K. We also show that the persistence of DB stars with no hydrogen features at low temperatures is difficult to reconcile with a scenario involving accretion from the interstellar medium, often invoked to account for the observed hydrogen abundances in DBA stars. We present evidence for the existence of two different evolutionary channels that produce DB white dwarfs: the standard model where DA stars are transformed into DB stars through the convective dilution of a thin hydrogen layer, and a second channel where DB stars retain a helium-atmosphere throughout their evolution. We finally demonstrate that the instability strip of pulsating V777 Her white dwarfs contains no nonvariables, if the hydrogen content of these stars is properly accounted for.Comment: 74 pages including 30 figures, accepted for publication in the Astrophysical Journa

Mass spectrometer calibration of Cosmic Dust Analyzer

The time of flight mass spectrometer of the Cosmic Dust Analyzer (CDA) instrument aboard the Cassini spacecraft, is expected to be placed in orbit about Saturn to sample the ring material and satellite impact ejecta. Upon impact of an incident dust particle against the target plate at velocities of 5-100 km/s, some 10–8 to 10–5 times the particle mass of positive valence, single-charged ions is induced. These are analyzed via a time-of-flight mass spectrometer. Initial experiments employing a pulsed N2 laser (>300 µJ/pulse, 4ns, 337nm) acting on a suite of samples are described. The laser beam is focussed to deliver the light pulses onto a laser power density (1011 W/cm2) to simulate the impact of particles. Laser ionization produced a charge of 4.6 pC per pulse for aluminum alloy. Estimating that each Al+1 ion require energy of 5.98 eV ionization energy/ion implies that 10–5% of the laser energy produced ions and the present system has a 5% efficiency of collecting the laser-irradiation induced ions. Employing a multi-channel plate detector in this mass spectrometer yields for Al-Mg-Cu alloy and kamacite (Fe-Ni mineral) targets well defined peaks at 24 (Mg+1), 27 (Al+1) and 64 (Cu+1), and 56 (Fe+1), 58 (Ni+1) and 60 (Ni+1) dalton, respectively

New results on GP Com

We present high resolution optical and UV spectra of the 46 min orbital period, helium binary, GP Com. Our data contains simultaneous photometric correction which confirms the flaring behaviour observed in previous optical and UV data. In this system all lines show a triple peaked structure where the outer two peaks are associated with the accretion disc around the compact object. The main aim of this paper is to constrain the origin of the central peak, also called ``central spike''. We find that the central spike contributes to the flare spectra indicating that its origin is probably the compact object. We also detect that the central spike moves with orbital phase following an S-wave pattern. The radial velocity semiamplitude of the S-wave is ~10 km/s indicating that its origin is near the centre of mass of the system, which in this case lies very close to the white dwarf. Our resolution is higher than that of previous data which allows us to resolve structure in the central peak of the line. The central spike in three of the HeI lines shows another peak blueshifted with respect to the main peak. We propose that one of the peaks is a neutral helium forbidden transition excited in a high electron density region. This forbidden transition is associated with the permitted one (the stronger peak in two of the lines). The presence of a high electron density region again favours the white dwarf as their origin.Comment: 14 pages, 16 figures. Accepted for publication in A&

Virtue and austerity

Virtue ethics is often proposed as a third way in health-care ethics, that while consequentialism and deontology focus on action guidelines, virtue focuses on character; all three aim to help agents discern morally right action although virtue seems to have least to contribute to political issues, such as austerity. I claim: (1) This is a bad way to characterize virtue ethics. The 20th century renaissance of virtue ethics was first proposed as a response to the difficulty of making sense of ‘moral rightness’ outside a religious context. For Aristotle the right action is that which is practically best; that means best for the agent in order to live a flourishing life.There are no moral considerations besides this. (2) Properly characterized, virtue ethics can contribute to discussion of austerity. A criticism of virtue ethics is that fixed characteristics seem a bad idea in ever-changing environments; perhaps we should be generous in prosperity, selfish in austerity. Furthermore, empirical evidence suggests that people indeed do change with their environment. However, I argue that virtues concern fixed values not fixed behaviour; the values underlying virtue allow for different behaviour in different circumstances: in austerity, virtues still give the agent the best chance of flourishing. Two questions arise. (a) In austere environments might not injustice help an individual flourish by, say, obtaining material goods? No, because unjust acts undermine the type of society the agent needs for flourishing. (b) What good is virtue to those lacking the other means to flourish? The notion of degrees of flourishing shows that most people would benefit somewhat from virtue. However, in extreme circumstances virtue might harm rather than benefit the agent: such circumstances are to be avoided; virtue ethics thus has a political agenda to enable flourishing. This requires justice, a fortiori when in austerity

Mass spectrometer calibration of Cosmic Dust Analyzer

The time-of-flight (TOF) mass spectrometer (MS) of the Cosmic Dust Analyzer (CDA) instrument aboard the Cassini spacecraft is expected to be placed in orbit about Saturn to sample submicrometer-diameter ring particles and impact ejecta from Saturn's satellites. The CDA measures a mass spectrum of each particle that impacts the chemical analyzer sector of the instrument. Particles impact a Rh target plate at velocities of 1-100 km/s and produce some 10^(−8) to 10^(−5) times the particle mass of positive valence, single-charged ions. These are analyzed via a TOF MS. Initial tests employed a pulsed N2 laser acting on samples of kamacite, pyrrhotite, serpentine, olivine, and Murchison meteorite induced bursts of ions which were detected with a microchannel plate and a charge sensitive amplifier (CSA). Pulses from the N_2 laser (10^(11) W/cm^2) are assumed to simulate particle impact. Using aluminum alloy as a test sample, each pulse produces a charge of ∼4.6 pC (mostly Al^(+1)), whereas irradiation of a stainless steel target produces a ∼2.8 pC (Fe^(+1)) charge. Thus the present system yields ∼10^(−5)% of the laser energy in resulting ions. A CSA signal indicates that at the position of the microchannel plate, the ion detector geometry is such that some 5% of the laser-induced ions are collected in the CDA geometry. Employing a multichannel plate detector in this MS yields for Al-Mg-Cu alloy and kamacite targets well-defined peaks at 24 (Mg^(+1)), 27(Al^(+1)), and 64 (Cu^(+1)) and 56 (Fe^(+1)), 58 (Ni^(+1)), and 60 (Ni^(+1)) dalton, respectively