An Integrated Approach to the Teaching of Numerical Methods to Engineering Students

In Technological University Dublin, historically, numerical methods were taught to engineering students using a format of traditional mathematics lectures, to a large class group consisting of students from five different engineering disciplines, complemented by small class tutorials. Assessment was by a single, written exam only. In order to improve the overall effectiveness of the students’ learning experience, it was deemed beneficial to also introduce practical computing classes in which the students would be required to apply the general mathematical methods covered in lectures to discipline-specific examples. Three different practical computing assignments were devised for the students to undertake, and 20% of the marks for the course were allocated to these assignments. The numerical problems considered were the solution of ordinary differential equations (ODEs) and partial differential equations (PDEs) using the finite-difference method; the solution of first-and second-order ODEs using Runge–Kutta; and the solution of first- order ODEs using Milne-Simpson. It was hoped that students would find this integrated approach engaging and formative in their understanding of numerical methods and their application to real-world engineering problems. To ascertain if this was the case, an anonymous, online survey of the students involved was conducted, along with a number of interviews of individual students. In addition, a comparison was carried out between these students’ grades, and grades from years prior to the introduction of the practical computing classes. The results of both the survey and the grade analysis will be presented in this paper

Weak Lensing with SDSS Commissioning Data: The Galaxy-Mass Correlation Function To 1/h Mpc

(abridged) We present measurements of galaxy-galaxy lensing from early commissioning imaging data from the Sloan Digital Sky Survey (SDSS). We measure a mean tangential shear around a stacked sample of foreground galaxies in three bandpasses out to angular radii of 600'', detecting the shear signal at very high statistical significance. The shear profile is well described by a power-law. A variety of rigorous tests demonstrate the reality of the gravitational lensing signal and confirm the uncertainty estimates. We interpret our results by modeling the mass distributions of the foreground galaxies as approximately isothermal spheres characterized by a velocity dispersion and a truncation radius. The velocity dispersion is constrained to be 150-190 km/s at 95% confidence (145-195 km/s including systematic uncertainties), consistent with previous determinations but with smaller error bars. Our detection of shear at large angular radii sets a 95% confidence lower limit $s>140^{\prime\prime}$, corresponding to a physical radius of $260h^{-1}$ kpc, implying that galaxy halos extend to very large radii. However, it is likely that this is being biased high by diffuse matter in the halos of groups and clusters. We also present a preliminary determination of the galaxy-mass correlation function finding a correlation length similar to the galaxy autocorrelation function and consistency with a low matter density universe with modest bias. The full SDSS will cover an area 44 times larger and provide spectroscopic redshifts for the foreground galaxies, making it possible to greatly improve the precision of these constraints, measure additional parameters such as halo shape, and measure the properties of dark matter halos separately for many different classes of galaxies.Comment: 28 pages, 11 figures, submitted to A

High-Redshift Quasars Found in Sloan Digital Sky Survey Commissioning Data II: The Spring Equatorial Stripe

This is the second paper in a series aimed at finding high-redshift quasars from five-color (u'g'r'i'z') imaging data taken along the Celestial Equator by the Sloan Digital Sky Survey (SDSS) during its commissioning phase. In this paper, we present 22 high-redshift quasars (z>3.6) discovered from ~250 deg^2 of data in the spring Equatorial Stripe, plus photometry for two previously known high-redshift quasars in the same region of sky. Our success rate of identifying high-redshift quasars is 68%. Five of the newly discovered quasars have redshifts higher than 4.6 (z=4.62, 4.69, 4.70, 4.92 and 5.03). All the quasars have i* < 20.2 with absolute magnitude -28.8 < M_B < -26.1 (h=0.5, q_0=0.5). Several of the quasars show unusual emission and absorption features in their spectra, including an object at z=4.62 without detectable emission lines, and a Broad Absorption Line (BAL) quasar at z=4.92.Comment: 28 pages, AJ in press (Jan 2000), final version with minor changes; high resolution finding charts available at http://www.astro.princeton.edu/~fan/paper/qso2.htm

Death and organization: Heidegger’s thought on death and life in organizations

Mortality has not been given the attention it deserves within organization studies. Even when it has been considered, it is not usually in terms of its implications for own lives and ethical choices. In particular, Heidegger’s writing on death has been almost entirely ignored both in writing on death and writing on organizational ethics, despite his insights into how our mortality and the ethics of existence are linked. In this paper, we seek to address this omission by arguing that a consideration of death may yield important insights about the ethics of organizational life. Most important of these is that a Heideggerian approach to death brings us up against fundamental ethical questions such as what our lives are for, how they should be lived and how we relate to others. Heideggerarian thought also reconnects ethics and politics, as it is closely concerned with how we can collectively make institutions that support our life projects rather than thwart or diminish them

The structures and properties of proton- and alkali-bound cysteine dimers

The proton-, lithium-, and sodium-bound cysteine dimers have been investigated in a joint computational and experimental infrared multiple photon dissociation (IRMPD) study. IRMPD spectra in the 1000–2000 cm−1 region show that protonation is localized on an amine group, and that intermolecular hydrogen bonding occurs between the protonated amine and the carbonyl oxygen of the neutral Cys moiety. Alkali-bound dimers adopt structures reminiscent of those observed for the monomeric Cys·Li+ and Cys·Na+ species. Calculations of the heavier Cys2·M+ (M = K, Rb or Cs) species suggest that these are significantly less strongly bound than the lighter (M = H, Li, or Na) dimers.We gratefully acknowledge high performance computing support from the SHARCNET consortium of Compute Canada. We are also grateful to the Centre Laser Infrarouge dOrsay (CLIO) team and technical support staff for the valuable assistance and hospitality. The authors would like to acknowledge financial support from the Natural Sciences and Engineering Research Council (NSERC) of Canada

Input Subsidies to Improve Smallholder Maize Productivity in Malawi: Toward an African Green Revolution

Recent hikes in food prices have created economic and social turmoil in many African countries. But in Malawi, fertilizer and seed subsidies have enabled small-scale farmers to improve maize productivity and achieve food security